THE CLIMATE WEATHER EYE

  
 
Sunset from Western Australia                            Photo: John Maunder 
 

 "The Sun pays no heed to human committees"

*This phrase with a minor change is given in a NASA release on "New Solar Cycle Prediction" on May 29 2009 (see http://science.nasa.gov/headlines/y2009/29may_noaaprediction.htm 

Last Update November 18, 2019

The Weekend Sun ( New Zealand) is published each Friday and contains a range of local information including comments from several columnists. During part of 2012, I provided a "Weather Eye" comment which was published on the second and fourth Friday of each month.

 
From  March 2013 my column is continuing and is now published each week on Sunlive.
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WEATHEREYE #340


The Southern Oscillation Index

Weather Eye
with John Maunder

The Southern Oscillation Index (SOI) is a standardized index based on the observed sea level pressure differences between Tahiti and Darwin, Australia.

The SOI is a leading measure of the large-scale fluctuations in air pressure occurring between the western and eastern tropical Pacific (i.e., the state of the Southern Oscillation) during El Niño and La Niña episodes.

In general, smoothed time series of the SOI correspond very well with changes in ocean temperatures across the eastern tropical Pacific. The negative phase of the SOI represents below-normal air pressure at Tahiti and above-normal air pressure at Darwin. The positive phase of the SOI represents above-normal air pressure at Tahiti and below-normal air pressure at Darwin.

Prolonged periods of negative SOI values coincide with abnormally warm ocean waters across the eastern tropical Pacific typical of El Niño episodes. In contrast, prolonged periods of positive SOI values coincide with abnormally cold ocean waters across the eastern tropical Pacific typical of La Niña episodes. Sustained negative values of the SOI below −8 often indicate El Niño episodes.These negative values are usually accompanied by sustained warming of the central and eastern tropical Pacific Ocean, a decrease in the strength of the Pacific Trade Winds.

Sustained positive values of the SOI above +8 are typical of a La Niña episode.They are associated with stronger Pacific trade winds and warmer sea temperatures to the north of Australia. Waters in the central and eastern tropical Pacific Ocean become cooler during this time.

The graph below ( from the Australian Bureau of Meteorology, BOM) shows monthly values of the SOI from 1880 to November 2019.

The 30-day Southern Oscillation Index (SOI) for the 30 days ending 10 November was −5.7. The 90-day value was −9.1. The 30-day SOI values have remained fairly similar and within the ENSO-neutral range for about three and a half weeks.

Sustained negative values of the SOI below −7 typically indicate El Niño while sustained positive values above +7 typically indicate La Niña. Values between +7 and −7 generally indicate neutral conditions.

El Nino and La Nina weather affects over New Zealand (Source Niwa)

During El Niño, New Zealand tends to experience stronger or more frequent winds from the west in summer, typically leading to drought in east coast areas and more rain in the west.

In winter, the winds tend to be more from the south, bringing colder conditions to both the land and the surrounding ocean.

In spring and autumn south–westerly winds are more common.

La Niña events have different impacts on New Zealand's climate. More north–easterly winds are characteristic, which tend to bring moist, rainy conditions to the north–east of the North Island, and reduced rainfall to the south and south–west of the South Island.

Therefore, some areas, such as central Otago and South Canterbury, can experience drought in both El Niño and La Niña.

Warmer than normal temperatures typically occur over much of the country during La Niña, although there are regional and seasonal exceptions.

Although ENSO events have an important influence on New Zealand's climate, it accounts for less than 25 per cent of the year to year variance in seasonal rainfall and temperature at most New Zealand measurement sites.

For further information see: https://sites.google.com/images/climatediceandthebutterfly/

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The physicist Leo Szilard once announced to his friend Hans Bethe that he was thinking of keeping a diary: 'I don't intend to publish, I am merely going to record the facts for the information of God.' 'Don't you think God knows the facts?' Bethe asked. 'Yes' said Szilard. ‘He knows the facts, but he does not know THIS version of the facts'

"(From Hans Christian von Baeyer, "Taming the Atom" (from the preface paragraph in "A Short History of Nearly Everything", by Bill Bryson, A Black Swan Book,



Tauranga October Rainfalls 1898-2019

Weather Eye
with John Maunder

The graph below shows the range of Tauranga's October rainfalls, from an extreme high of 357 mm in 1916 to a low of only 7 mm in 1984.

The second wettest October was 1928, when 269 mm was recorded; and the second driest October was in 1928, when only 11 mm fell.

The long-term average rainfall for Tauranga in the month of October is 110 mm.

The rainfall in October 2019 was 91 mm.

The graph of the October rainfall shows generally normal variations from year to year.

Since 1898, there have been 11 October months with a rainfall of 200 mm or more (10 of which occurred during the period 1900-1958), and only one October month since then has recorded this much. Ten October months have also experienced rainfalls of 25 mm or less.

In chronological order the eleven wettest October months are 1900, 1905, 1916, 1918, 1921, 1926, 1928, 1941, 1952, 1958, and 1983. In contrast the eleventh driest October months are 1906, 1938, 1963, 1965, 1969, 1973, 1984, 1993, 2010, 2013, and 2015.

For further information see: https://sites.google.com/images/climatediceandthebutterfly/




Tauranga October Average Afternoon Temperatures 1913-2019

Weather Eye
with John Maunder

Temperatures have been recorded in the Tauranga area at several sites in the last 100 years, including the current Tauranga Airport site from June 1990.

The graph shows details of the average daily maximum temperatures (called simply ‘afternoon') for Tauranga for October from 1913-2019.

The average afternoon temperature for October 2019 for Tauranga was 18.5 degrees C, which was just 0.4 degrees milder than the average over the last 95 years.

The long-term average afternoon temperature in October for Tauranga is 18.1 degrees Celsius, ranging from the cool October months of 1964 (15.7 degrees Celsius), and 1992 (16.5 degrees Celsius), to the warm October months of 2013 (20.3 degrees Celsius), and 1915 (19.9 degrees Celsius).

The graph of the average afternoon temperatures for October shows generally normal variations from October to October during the last 100 years.

The average October afternoon temperatures during the 50 years from 1963-2011 of 18.0 degrees Celsius is slightly cooler than the 18.3 degrees Celsius recorded in the 50 years from 1914-1961.

From 1913 to 2018, there have been fifteen October months with an average afternoon temperature of 19.0 degrees Celsius or more; and eight October months have had an average afternoon temperature of 17.0 degrees Celsius or less.

The five warmest October months (in terms of afternoon temperatures), on record, in chronological order, are 1913, 1915, 1940, 2013, and 2015.

By contrast, the fifth coolest October months (in terms of afternoon temperatures), on record, in chronological order, are 1941, 1964, 1978, 1982, and 1992.

For further information see: https://sites.google.com/images/climatediceandthebutterfly/

The physicist Leo Szilard once announced to his friend Hans Bethe that he was thinking of keeping a diary: 'I don't intend to publish, I am merely going to record the facts for the information of God.' 'Don't you think God knows the facts?' Bethe asked. 'Yes' said Szilard. ‘He knows the facts, but he does not know THIS version of the facts'

"(From Hans Christian von Baeyer, "Taming the Atom" (from the preface paragraph in "A Short History of Nearly Everything", by Bill Bryson, A Black Swan Book, 2004)



Tropospheric Temperatures 1979 to September 2019

Weather Eye
with John Maunder

The chart below shows that since 1979, when reliable satellite observations became available, there has been little overall trend in the average tropospheric temperatures, apart from milder/warmer temperatures since about 1997, and two significant warm periods associated with the El Nino events in 1998 and 2015-16.

The latest global average temperatures of the troposphere updated to October 2019 - observed from US National Oceanic and Atmospheric Administration satellites – are computed by the University of Alabama at Huntsville in the United States. The data shows variations from the 30 year period 1981-2010.

Since 1979, NOAA satellites have been carrying instruments which measure the natural microwave thermal emissions from oxygen in the atmosphere. The intensity of the signals these microwave radiometers measure at different microwave frequencies is directly proportional to the temperature of different, deep layers of the atmosphere. Every month, researchers at the University of Alabama (Dr John Christy and Dr Roy Spencer) update global temperature datasets that represent the piecing together of the temperature data from a total of fourteen instruments flying on different satellites over the years.

The graph above represents the latest update; updates are usually made within the first week of every month. Contrary to some reports, the satellite measurements are not calibrated in any way with the global surface-based thermometer records of temperature. They instead use their own on-board precision redundant platinum resistance thermometers calibrated to a laboratory reference standard before launch.

The troposphere is the lowest layer of Earth's atmosphere.

It contains approximately 75 per cent of the atmosphere's mass and 99 per cent of its water vapour and aerosols.

The average depth of the troposphere is approximately 17 km in the middle latitudes.

The latest data for September 2019 is +0.61 degrees C.

The coolest months since 1979 were September 1984, with minus 0.49 degrees Celsius, and November 1984, with minus 0.42 degrees Celsius.

The warmest months were February 2016 with plus 0.83 degrees C, February and April 1998, both plus 0.76 degrees Celsius, and March 2016 plus 0.73 degrees, and April 2016 plus 0.73 degrees Celsius.

The chart shows the El Nino warming in the 1998 period, and 2015-16, and the Mount Pinatubo, volcanic cooling during 1992-1993.

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The physicist Leo Szilard once announced to his friend Hans Bethe that he was thinking of keeping a diary: 'I don't intend to publish, I am merely going to record the facts for the information of God.' 'Don't you think God knows the facts?' Bethe asked. 'Yes' said Szilard. ‘He knows the facts, but he does not know THIS version of the facts'

"(From Hans Christian von Baeyer, "Taming the Atom" (from the preface paragraph in "A Short History of Nearly Everything", by Bill Bryson, A Black Swan Book, 2004)




Do Solar Magnetic Variations affect the Climate?

Weather Eye
with John Maunder

The Sun has an associated magnetic field known as the interplanetary magnetic field (IMF). When this interacts with the Earth’s magnetic field some changes occur in the Earth’s atmospheric circulation.

From time to time, as it sweeps past the Earth, the direction of the IMF changes from towards the Earth to away from the Earth. The time of this change varies but on average could be regarded as about once every 12 days.

In a study using data for the 21-year period 1997-2017 (published in the Meteorological Society of New Zealand Newsletter 156: Autumn 2019, Graham Ward mailto:gfaw@actrix.co.nz) has found what appear to be significant changes in the Southern Oscillation dex (SOI) at times when the IMF changes direction. These events are known as IMF sector boundary crossings. Data giving the time and direction of these crossings were obtained for this study from the Wilcox Solar Observatory (Svalbard Sector Boundary List 1926 – present).

The Wilcox Solar Observatory (WSO) began collecting daily observations of the Sun’s global (or mean) magnetic field in May 1975, with the goal of understanding changes in the Sun and how those changes affect the Earth. That science is now called space weather. Since May 1976 daily low-resolution maps of the Sun's magnetic field have been made at the WSO, along with observations of solar surface motions. The observatory is located in the foothills just west of the Stanford University campus. Current research topics include space weather, the large-scale magnetic field, and the solar cycle.

The SOI is effectively a measure of the barometric pressure difference between Tahiti and Darwin and can be regarded as a key indicator of the overall state of the global climate at the time. The chart below from the Australian Bureau of Meteorology shows the values of the SOI from January 2017 to October 2019. .

The changes in the SOI at the time of each IMF change of direction (sector boundary crossing) were found to be very large on the average during the two extreme El Nino years 1997 and 2015 (accompanied by very low negative values of the SOI), and also during the extreme La Nina years 2010 and 2011 (accompanied by very high positive values of the SOI). Values of the SOI were generally less (positive or negative) in the remaining years of the study and the apparent effect on the SOI at the time of each sector boundary crossing in those years generally smaller, but still noteworthy.

The revelation of these results leaves us with one big question:

“As it seems most unlikely that the results are due to pure chance, what exactly is the mechanism causing them?”

Are interplanetary/solar magnetic (tidal) forces responsible? Could these influences be largely or at least partly the cause of the global climate changes that we are now witnessing?

A paper by Italian scientists SA Capuano et al published in 2018 offers a further insight into this subject. The extract from the published paper includes the following:

The debated question on the possible relation between the Earth’s magnetic field and climate has been usually focused on direct correlations between different time series representing both systems.

However, the physical mechanism able to potentially explain this connection is still an open issue. Finding hints about how this connection could work would suppose an important advance in the search of an adequate physical mechanism.

Here, we propose an innovative information-theoretic tool, i.e. the transfer entropy (which is the transfer of information between two random processes) as a good candidate for this scope because is able to determine, not simply the possible existence of a connection, but even the direction in which the link is produced.

We have applied this new methodology to two real time series, the South Atlantic Anomaly (SAA) area extent at the Earth’s surface (representing the geomagnetic field system) and the Global Sea Level (GSL) rise (for the climate system) for the last 300 years, to measure the possible information flow and sense between them.

This connection was previously suggested considering only the long-term trend while now we study this possibility also in shorter scales. The new results seem to support this hypothesis, with more information transferred from the SAA to the GSL time series, with about 90% of confidence level.

This result provides new clues on the existence of a link between the geomagnetic field and the Earth’s climate in the past and on the physical mechanism involved because, thanks to the application of the transfer entropy, we have determined that the sense of the connection seems to go from the system that produces geomagnetic field to the climate system.

Of course, the connection does not mean that the geomagnetic field is fully responsible for the climate changes, rather that it is an important driving component to the variations of the climate.

Sunspots Update

As of October 21, there have been 213 days in 2019 when the sun has had no sunspots. Data on spotless days are available from 1849 and the year 1913 with 311 spotless days is the highest spotless calendar year. The year 2019 with 213 spotless days is currently the 11th most spotless days year ( since 1849) .

For further information on a range of weather and climate and climate matters see: https://sites.google.com/images/climatediceandthebutterfly/

The physicist Leo Szilard once announced to his friend Hans Bethe that he was thinking of keeping a diary: 'I don't intend to publish, I am merely going to record the facts for the information of God.' 'Don't you think God knows the facts?' Bethe asked. 'Yes' said Szilard. "He knows the facts, but he does not know THIS version of the facts'

"(From Hans Christian von Baeyer, "Taming the Atom" (from the preface paragraph in "A Short History of Nearly Everything", by Bill Bryson, A Black Swan Book, 2004)




Tauranga September Average Afternoon Temperatures 1913-2019

Weather Eye
with John Maunder

Temperatures have been recorded in the Tauranga area at several sites in the last 100 years, including the current Tauranga Airport site from June 1990.

The graph shows details of the average daily maximum temperatures (simply called “afternoon”) for Tauranga for September from 1913-2019.

The long-term average afternoon temperature in September for Tauranga is 16.6 degrees C, ranging from the “cool” September months of 1964 (14.8 degrees C), and 1977 (14.9 degrees C), to the “warm” September months of 1915 (18.4 degrees C), and 18.3 degrees in 1914.

The afternoon temperature for 2019 was 16.8 degrees C, which was the one of the coolest Septembers in the last decade.

The graph of the average afternoon temperatures for September shows generally "normal" variations from September to September during the last 100 years, but five of the warmest six September months occurred from 1913 to 1921.

From 1913 to 2019, there have been ten September months with an average afternoon temperature of 17.5 degrees C or more, and eight September months with an average afternoon temperature of less than 15.4 degrees C.

The tenth “warmest” September months (in terms of afternoon temperatures) on record, in chronological order, are 1913, 1914, 1915, 1916, 1921, 1926, 1940, 2006, 2009 and 2014.

By contrast, the eighth “coolest” September months (in terms of afternoon temperatures) on record, in chronological order, are 1935, 1964, 1967, 1977, 1992, 1993, 1994 and 1997.

The average afternoon temperature during September for the period 1914-62 was 16.6 degrees, compared with 16.5 degrees from 1963-2011.

For further information see: https://sites.google.com/images/climatediceandthebutterfly/


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Tauranga September Rainfalls

Weather Eye
with John Maunder

Rainfalls for the month of September have been recorded in Tauranga since 1898, except for 1904, 1907, 1908, and 1909.

The graph below shows the range of rainfalls from an extreme high of 274 mm in 1973 to a low of only 16 mm in 1965.

The second wettest September was in 1900, when 256 mm was recorded, and the second driest September was in 1944, when only 27 mm fell. The long-term average rainfall for Tauranga for September is 105 mm.

The graph of the September rainfall shows normal variations from year to year. Since 1898, there have been five Septembers with a rainfall of 200 mm or more (four of which occurred during the period 1900 to 1928, but there's only been one since then), compared with seven September months with a rainfalls of 40 mm or less.

The rainfall for September 2019 was 97 mm.

In chronological order, the ten wettest September months (rainfalls over 180 mm) are 1900,1912,1919,1923,1928,1946,1960,1969,1971,1973, and 2017.

In contrast the twelfth driest September months (rainfalls of 50 mm or less) are 1910, 1913, 1914, 1921, 1922, 1944, 1965, 1993, 1987, 2006, 2011 and 2018.

The average rainfall for Tauranga for September for the 50 years 1961-2010 of 103 mm is similar to the rainfall for the previous 50 years (1910-1960).

For further information on a range of weather/climate matters see https://sites.google.com/images/climatediceandthebutterfly/


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Climate Change 2019 and Villach 1985: What is the connection?

Weather Eye
with John Maunder

Among the many climate science meetings I have attended, the most significant, at least in term of climate change is concerned, was my involvement in the UN sponsored International Conference held in the beautiful town Villach, in Austria in October 1985.

One hundred experts from 30 countries attended the meeting (in contrast to ten to twenty thousand who now attend such meetings), and I was privileged to be the only New Zealander invited.

We were all there as experts - and not representing our respective organisations - in various fields of science, endeavouring to do the best we could in looking at the complexities of climate science.

This conference predated by three years the establishment of the Intergovernmental Panel on Climate Change (IPCC) established by the World Meteorological Organization (WMO) and the United Nations Environment Programme (UNEP).

The first session of the IPCC was held in Geneva in November 1988 and again I was the only person from New Zealand invited to participate.

Among the principal findings of this conference was that "while other factors, such as aerosol concentration, changes in solar energy input, and changes in vegetation, may also influence climate, the greenhouse gases are likely to be the most important cause of climate change over the next century”.

At that time, even though I was partly responsible for the writing of the above paragraph, I along with a few of my colleagues, had some misgivings about this phrase, and were somewhat surprised that within a year ‘human-induced global warming' caught the imagination of much of the world. Indeed today, not a day goes by without some mention of ‘global warming', climate change, emission trading schemes, etc, all terms which up until 1980’s were the preserve of academic text books.

Despite this concern, a colleague of mine from Australia, Bill Kininmonth, who in 2004 wrote a book called "Climate Change - A Natural Hazard" has mentioned to me on several occasions that I have changed from being a ‘gamekeeper' and become a ‘poacher'. Whether that is true is a matter of opinion. However, irrespective of my personal views on the matter, it is clear that there are two main views held by climate scientists and others on the subject of global warming and climate change.

First, those who are mainly involved in the Intergovernmental Panel on Climate Change( IPCC) and many or most government scientists, plus others, such as Al Gore, and many politicians and most journalists who consider that humans activities, including domestic animals, are the prime cause of recent changes in the climate;

Second, those - in the main some university scientists, many retired climatologists, and a minority of politicians and journalists, who consider that “nature” is the main cause of changes in the climate.

Thirty years ago, it was unconceivable that the New Zealand Government would have a Minister of Climate Change; indeed back then, as weather forecasters and climatologists we just got on with our job of making the best possible weather forecast and providing the best climate advice to all those who requested information, without guidance or interference from the Government of the day. How things have changed!

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For further information see: https://sites.google.com/images/climatediceandthebutterfly/

The physicist Leo Szilard once announced to his friend Hans Bethe that he was thinking of keeping a diary: 'I don't intend to publish, I am merely going to record the facts for the information of God.' 'Don't you think God knows the facts?' Bethe asked. 'Yes' said Szilard. ‘He knows the facts, but he does not know THIS version of the facts'

"(From Hans Christian von Baeyer, "Taming the Atom" (from the preface paragraph in "A Short History of Nearly Everything", by Bill Brysn, A Black Swan Book, 2004)

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https://www.sunlive.co.nz/blogs/13816-solar-activity-and-spotless-days.html

Solar Activity and Spotless Days

Weather Eye
with John Maunder

The NASA solar physics website, and other websites such as the Royal Observatory of Belgium, include information on sunspot numbers, spotless days, the ‘Maunder Minimum' and sunspot cycle predictions.

A sunspot is a relatively dark, sharply defined region on the solar disc – marked by an umbra, dark area, which is 2000 degrees cooler than the effective photospheric temperature. The average diameter of a sunspot is 4000 km, but they can exceed 200,000 km.

The sunspot index is updated monthly and is available from 1749. The last time the value was much above 200 was in August 1990.

Solar observers have noticed that since mid-2016, the Sun has occasionally been devoid of sunspots. These spotless disks will gradually become a familiar feature as the solar cycle is heading for its next minimum, currently expected by the end of this decade and probably has already started. The number of spotless days can vary significantly from one solar cycle transit to another. For example, during the previous minimum solar cycle 24 (around 2008), 817 spotless days were recorded, whereas the minimum period leading into solar cycle 23 (around 1996) counted only 309 such blemishless days.

The current solar cycle 24 will gradually give way to the new solar cycle 25, and several consecutive days and even periods of 30 or more consecutive days without sunspots will become the norm. the Belgium SILSO website has created a “Spotless Days page”. This page contains graphs and tables on the accumulated number of spotless days, stretches of spotless days, and comparisons to other solar cycles.

The previous minimum (solar cycle 24) surprised many solar scientists and solar observers by being the deepest in nearly 90 years. Will the upcoming solar cycle minimum show as many spotless days, or will solar cycle 25 take off much faster than expected? The “Spotless Days page” provides a front-row seat on the current status of the solar cycle minimum and the number of spotless days. Enjoy!

Since 1849, there have been 114 years (including 2019) with at least one spotless day. The chart below shows the 25 years with the highest number of spotless days. 1913 had 311 spotless days, while 2008 ranks fourth in years with a spotless sun (265 days). With 208 days, 2018 (green bar) has nested itself into the top 25 years with most spotless days.

As of September 22, 2019 there have been 189 days in 2019 without sunspots, and with 100 days remaining in the calendar year, the forecast by many solar scientists is that the 2019 will have over 250 days with sunspots, which would make 2019 the ninth most “spotless” year since records began in 1849.

The ‘Maunder Minimum' is the name given to the period from 1645 to 1715 when the number of sunspots – ‘storms' on the sun – became almost zero. The period is named after the solar astronomer Edward Walter Maunder (1851-1928), who was working at The Royal Observatory at Greenwich when he discovered the dearth of sunspots during this period.

During one 30-year period within the Maunder Minimum there were only about 50 sunspots compared with a more typical 40,000. Maunder was a driving force in the foundation of the British Astronomical Association and a Fellow of the Royal Astronomical Society.The sun was well observed during the period of the Maunder Minimum and this lack of sunspots is well documented. This period of solar inactivity corresponded to a climatic period called the ‘Little Ice Age' when in Europe rivers that were normally ice-free, froze and snow fields remained at low altitudes throughout the year. There is evidence the sun had similar periods of inactivity during the years 1100-1250 and 1460-1550. Sunspots generally follow a cycle of about 11 years, but cycles have varied from eight-15 years.

The connection between solar activity and the earth's climate is an area of ongoing and sometimes controversial research.Time will tell whether the sun will once again go into another ‘Maunder Minimum' within the lifetime of the present generation with very many spotless days , but if this happens we're likely to have a much colder climate for a few decades.

The sunspot number for most days during the last 3 months is zero.

For further information on a range of weather and climate matters see: https://sites.google.com/images/climatediceandthebutterfly/






Tropospheric Temperatures 1979 to August 2019

Weather Eye
with John Maunder

The chart below shows that since 1979, when reliable satellite observations became available, there has been little change in the overall trend in the average tropospheric temperatures, apart from milder/warmer temperatures since about 1997, and two significant warm periods associated with the El Nino events in 1998 and 2015-16.

The latest global average temperatures of the troposphere updated to August 2019 - observed from US National Oceanic and Atmospheric Administration satellites – are computed by the University of Alabama at Huntsville in the United States. The data shows variations from the 30 year period 1981-2010.

Since 1979, NOAA satellites have been carrying instruments which measure the natural microwave thermal emissions from oxygen in the atmosphere. The intensity of the signals these microwave radiometers measure at different microwave frequencies is directly proportional to the temperature of different, deep layers of the atmosphere. Every month, researchers at the University of Alabama (Dr John Christy and Dr Roy Spencer) update global temperature datasets that represent the piecing together of the temperature data from a total of fourteen instruments flying on different satellites over the years.

The graph above represents the latest update; updates are usually made within the first week of every month. Contrary to some reports, the satellite measurements are not calibrated in any way with the global surface-based thermometer records of temperature. They instead use their own on-board precision redundant platinum resistance thermometers calibrated to a laboratory reference standard before launch.

The troposphere is the lowest layer of Earth's atmosphere.

It contains approximately 75 per cent of the atmosphere's mass and 99 per cent of its water vapour and aerosols.

The average depth of the troposphere is approximately 17 km in the middle latitudes.

The coolest months since 1979 were September 1984, with minus 0.49 degrees Celsius, and November 1984, with minus 0.42 degrees Celsius.

The warmest months were February 2016 with plus 0.83 degrees C, February and April 1998 both plus 0.76 degrees Celsius, and March 2016 and April 2016 plus 0.73 degrees Celsius.

The chart shows the El Nino warming in the 1998 period, and 2015-16, and the Mount Pinatubo, volcanic cooling during 1992-1993.

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In April 2015 Roy Spencer and his two colleagues published the following comment..

Version 6 of the UAH MSU/AMSU global satellite temperature dataset is by far the most extensive revision of the procedures and computer code we have ever produced in over 25 years of global temperature monitoring. The most significant changes from an end-user perspective are (1) a decrease in the global-average lower tropospheric (LT) temperature trend from +0.140 C/decade to +0.114 C/decade (December. 1978 through March. 2015); and (2) the geographic distribution of the LT trends, including higher spatial resolution. See the current webpage for further information.. https://www.drroyspencer.com/latest-global-temperatures/

For further information on a range of climate matters see: https://sites.google.com/images/theweatherclimateeye/

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The physicist Leo Szilard once announced to his friend Hans Bethe that he was thinking of keeping a diary: 'I don't intend to publish, I am merely going to record the facts for the information of God.' 'Don't you think God knows the facts?' Bethe asked. 'Yes' said Szilard. "He knows the facts, but he does not know THIS version of the facts'

"(From Hans Christian von Baeyer, "Taming the Atom" (from the preface paragraph in "A Short History of Nearly Everything", by Bill Bryson, A Black Swan Book, 2004)


Tauranga August Average Afternoon Temperatures 1913-2019

Weather Eye
with John Maunder

Temperatures have been recorded in the Tauranga area at several sites in the last 100 years, including the current Tauranga Airport site from June 1990.

The graph shows details of the average daily maximum temperatures, called simply ‘afternoon' for Tauranga for August from 1913-2019. The average for August 2019 was 15.5 degrees Celsius.

The long-term average afternoon temperature in August for Tauranga is 14.8 degrees Celsius. The coolest August months have been 1932 with 13.8 degrees Celsius, and 1941 and 1992 recording 13.9 degrees Celsius.

The warm August months have been 2013 with 16.7 degrees Celsius, and 1915 with 16.4 degrees Celsius, while 2009 had 16.2 degrees Celsius.

The graph of the average afternoon temperatures for August shows generally normal variations from August to August during the last 100 years.

But several recent August months have been a little warmer than others since 1913. This includes August 2013, the warmest on record with a temperature of 16.7 degrees Celsius, which was 1.9 degrees Celsius above average.

From 1913 to 2019, there have been 11 August months with an average afternoon temperature of 15.8 degrees Celsius or more.

Thirteen August months have had an average afternoon temperature of less than 14.3 degrees Celsius.

The sixth warmest August months – in terms of afternoon temperatures – on record in chronological order are: 1915, 1967, 1971, 2009, 2012 and 2013. By contrast, the fifth coolest August months – in terms of afternoon temperatures – on record, in chronological order are: 1932, 1941, 1966, 1992 and 2004.

The average afternoon temperatures during August for the period 1914-1963 were 14.7 degrees Celsius, compared with 15.0 degrees Celsius from 1964 to 2013.

For further information on a range of weather/climate matters see: https://sites.google.com/images/theweatherclimateeye/

Tauranga August Rainfalls 1898-2019

Weather Eye
with John Maunder

Rainfalls for the month of August have been recorded in Tauranga since 1898, except for 1904, 1907, 1908 and 1909.

From January 1898 to December 1904, the observation site was described as the Tauranga Harbour, from November 1904 to April 1907 the site was described as simply ‘Tauranga'. From January 1910 to December 1923 the site was Waikareao, in Otumoetai; from January 1924 to September 1940 the site was at 148 Waihi Rd, in Judea; from October 1940 to January 1941 the site was at Te Puna; and from February 1941 to now, the site is Tauranga Airport.

The methodology use in adjusting the older sites to the current observing site is published in the ‘NZ Meteorological Service Miscellaneous Publication' No 180 in 1984.

It is considered that the homogeneous rainfall series described here is a fair and true record of what the rainfall would have been if the current observation site (Tauranga Airport) had been used since 1898. This should be coupled with the understanding that although standard accepted methodologies have been used, any adjustments are only estimates of what would have occurred if the location of the rainfall records had always been in the same place with the same surroundings and the same or similar recording gauge.

In terms of climate change (such as is it getting wetter or drier, or warmer or colder), the methodology used in computing an ‘official' set of climate observations is very important, as otherwise erroneous conclusions may be drawn.

The graph shows the range of rainfalls from an extreme high of 274 mm in 2010 to a low of only 17 mm in 1914.

The second wettest August was 1916 when 263 mm was recorded, and the second driest August was in 1982 when only 31 mm fell.

The long-term average rainfall for Tauranga for August is 124 mm. The rainfall for Tauranga for August 2019 was 74 mm.

The graph of the August rainfall shows normal variations from year-to-year.

There is a small decrease in the overall August rainfalls during the last 50 years – from 1961-2010 – from an average of 121 mm, compared with an average of 133 mm during the 50 years from 1911-1960. Since 1898, there have been 11 August months with a rainfall of 220 mm or more – with 10 occurring during 1900 to 1976 – and only one August month since then 2010, which was the highest rainfall for any August. Only five August months have had rainfalls of 50 mm or less.

Chronologically, the 11 wettest August months are 1913, 1916, 1920, 1927, 1938, 1942, 1957, 1965, 1970, 1976 and 2010.

In contrast, chronologically the five driest August months are 1914, 1921, 1982, 1983 and 2002.

For further information see:





Global Temperatures 1996 – July 2019

Weather Eye
with John Maunder

Global temperatures are compiled for various areas including global (land-ocean), global (meteorological stations), three latitude bands,

and hemispheric, by the Goddard Institute for Space Studies of NASA.

The graph shows the monthly mean global surface temperature anomaly from the base period 1951-1980, for the period 1996- July 2019.

For details see data.giss.nasa. (See graphs at the top right hand corner of the front web page and go to months)

The GISS Surface Temperature Analysis (GISTEMP) is an estimate of global surface temperature change. Graphs and tables are updated around the

middle of every month using current data files from NOAA GHCN v3 (meteorological stations), ERSST v4 (ocean areas), and SCAR (Antarctic stations),

combined as described in our December 2010 publication (Hansen et al. 2010). These updated files incorporate reports for the previous month and

also late reports and corrections for earlier month.

The basic GISS temperature analysis scheme was defined in the late 1970's when a method of estimating global temperature

change was needed for comparison with one-dimensional global climate models. The scheme was based on the finding that the correlation

of temperature change was reasonably strong for stations separated by up to 1200 km, especially at middle and high latitudes. This fact proved

sufficient to obtain useful estimates for global mean temperature changes.

The chart above shows that from 1997 to July 2019 there has been a small warming in the global monthly temperatures, and a relatively

warm period associated with the recent El Nino event.

For further information on a wide range of climate matters see https://sites.google.com/images/climatediceandthebutterfly/

The physicist Leo Szilard once announced to his friend Hans Bethe that he was thinking of keeping a diary: 'I don't intend to publish, I am merely going to record the facts for the information of God.' 'Don't you think God knows the facts?' Bethe asked. 'Yes' said Szilard. "He knows the facts, but he does not know THIS version of the facts' "(From Hans Christian von Baeyer, "Taming the Atom" (from the preface paragraph in "A Short History of Nearly Everything", by Bill Bryson, A Black Swan Book, 2004)



Tropospheric Temperatures 1979 to July 2019

Weather Eye
with John Maunder

The chart below shows that since 1979, when reliable satellite observations became available, there has been little change in the overall trend in the average tropospheric temperatures, apart from milder/warmer temperatures since about 1997, and two significant warm periods associated with the El Nino events in 1998 and 2015-16.

The latest global average temperatures of the troposphere updated to July 2019 - observed from US National Oceanic and Atmospheric Administration satellites – are computed by the University of Alabama at Huntsville in the United States. The data shows variations from the 30 year period 1981-2010.

Since 1979, NOAA satellites have been carrying instruments which measure the natural microwave thermal emissions from oxygen in the atmosphere. The intensity of the signals these microwave radiometers measure at different microwave frequencies is directly proportional to the temperature of different, deep layers of the atmosphere. Every month, researchers at the University of Alabama (Dr John Christy and Dr Roy Spencer) update global temperature datasets that represent the piecing together of the temperature data from a total of fourteen instruments flying on different satellites over the years.

The graph above represents the latest update; updates are usually made within the first week of every month. Contrary to some reports, the satellite measurements are not calibrated in any way with the global surface-based thermometer records of temperature. They instead use their own on-board precision redundant platinum resistance thermometers calibrated to a laboratory reference standard before launch.

The troposphere is the lowest layer of Earth's atmosphere.

It contains approximately 75 per cent of the atmosphere's mass and 99 per cent of its water vapour and aerosols.

The average depth of the troposphere is approximately 17 km in the middle latitudes.

The coolest months since 1979 were September 1984, with minus 0.49 degrees Celsius, and November 1984, with minus 0.42 degrees Celsius.

The warmest months were February 2016 with plus 0.83 degrees C, February and April 1998, both plus 0.76 degrees Celsius, and March 2016 plus 0.73 degrees, and April 2016 plus 0.73 degrees Celsius.

The chart shows the El Nino warming in the 1998 period, and 2015-16, and the Mount Pinatubo, volcanic cooling during 1992-1993.

****

In April 2015 Roy Spencer and his two colleagues published the following comment..

Version 6 of the UAH MSU/AMSU global satellite temperature dataset is by far the most extensive revision of the procedures and computer code we have ever produced in over 25 years of global temperature monitoring. The most significant changes from an end-user perspective are (1) a decrease in the global-average lower tropospheric (LT) temperature trend from +0.140 C/decade to +0.114 C/decade (December. 1978 through March. 2015); and (2) the geographic distribution of the LT trends, including higher spatial resolution. See the current webpage for further information.. https://www.drroyspencer.com/latest-global-temperatures/

For further information on a range of climate matters see: https://sites.google.com/images/climatediceandthebutterfly/

**********

The physicist Leo Szilard once announced to his friend Hans Bethe that he was thinking of keeping a diary: 'I don't intend to publish, I am merely going to record the facts for the information of God.' 'Don't you think God knows the facts?' Bethe asked. 'Yes' said Szilard. "He knows the facts, but he does not know THIS version of the facts'

"(From Hans Christian von Baeyer, "Taming the Atom" (from the preface paragraph in "A Short History of Nearly Everything", by Bill Bryson, A Black Swan Book, 2004)




Tauranga Average July Afternoon Temperatures 1913-2019

Weather Eye
with John Maunder

The graph below shows details of the average daily maximum temperatures, called ‘afternoon', for Tauranga for July from 1913-2019. The temperature for July 2019 was 15.8 degrees Celsius.

It's very common for areas such as Tauranga to have had different observation sites during the years, and readings from the earlier sites have been adjusted to the present site using standard climatologically procedures.The temperature series described here is a record of what the temperature would have been if the current observation site, Tauranga Airport, had been used throughout the period.

It's important to note, in considering climate change, the methodology used in computing an official set of climate observations is very important as otherwise erroneous conclusions may be drawn.

Traditionally, temperature observations have been recorded with a set of maximum and minimum temperature thermometers.

These record the daily maximum temperature, usually recorded in mid-afternoon, and daily minimum temperature, usually recorded just before dawn.

This analysis of temperatures for Tauranga is for average daily maximum temperatures.

The long-term average afternoon temperature in July for Tauranga is 14.1 degrees Celsius, ranging from cool July months of 1918 and 1939, both 12.3 degrees Celsius, and 1965, with 12.9 degrees Celsius, to the mild July months of 1916, 2010, and 2019 both 15.8 degrees Celsius, and 1915 with 15.7 degrees Celsius.
The graph of the average afternoon temperatures for July shows generally normal variations from July to July in the last 100 years.

But several July months since 1997 have been a little warmer than many of the July months since 1913.

From 1913 to 2019, there have been seven July months with an average afternoon temperature of 15.2 degrees Celsius or more, and 11 July months with an average afternoon temperature of less than 13.3 degrees Celsius.

The seventh mildest July months for afternoon temperatures on record, in chronological order are: 1915, 1916, 1917, 1984, 1998, 2000, and 2019.

By contrast, the seven coolest July months for afternoon temperatures on record, in chronological order are: 1918, 1929, 1935, 1939, 1963, 1965, and 1969.

The average afternoon temperature for Tauranga for July for 49 years from 1914-1962 was 14.0 degrees Celsius, compared with the average afternoon temperature for Tauranga for July for 49 years from 1963-2011 was 14.2 degrees Celsius.

For further information on a range of weather and climate matters see: https://sites.google.com/images/climatediceandthebutterfly/




Tauranga July Rainfalls 1898-2019

Weather Eye
with John Maunder

Rainfalls for the month of July have been recorded in Tauranga since 1898, except for 1904, 1907, 1908, and 1909.

The graph for the period 1898-2019 shows the range of rainfalls from an extreme high of 348 mm in 1951, to a low of only 2 mm in 1902.

The rainfall for July 2019 was 152 mm. The graph shows the second wettest July was 2012 when 328 mm was recorded, and the second driest July was in 1983 when only 22 mm fell.

The long-term average rainfall for Tauranga for July is 129 mm. The graph of the July rainfall shows ‘normal' variations from year to year.

There is a very small decrease in the overall July rainfalls during the last 50 years (1961-2010) from an average of 127 mm, compared with an average of 132 mm during the 50 years from 1911-1960.

Since 1898, there have been 13 July months with a rainfall of 200 mm or more, but only four July months with rainfalls of 40 mm or less.

The ten wettest July months (in chronological order) have been 1905, 1927, 1938, 1951,1963,1979,1988, 2007, 2008, and 2012. The ten driest July months ( in chronological order) have been 1902, 1918, 1922, 1949, 1969, 1975, 1983, 1997, 2001, and 2010,

For further information on a variety of weather and climate matters see

https://sites.google.com/images/climatediceandthebutterfly/






Arctic and Antarctic Temperatures ..... January 2000 to June 2019

Weather Eye
with John Maunder

Each month Professor Ole Humlum of the The University Centre in Svalbard (UNIS), in Norway publishes on the web his very comprehensive web site updating a large number of charts and related analyses of data from international sources such as NASA.. His latest website can be found at:

 

https://www.climate4you.com/Text/Climate4you

 

One example of what is contained in his web base are the charts of Arctic and Antarctic surface air temperatures from January 2000 to June 2019.

HadCRUT4 is a global temperature dataset, providing gridded temperature anomalies across the world as well as averages for the hemispheres and the globe as a whole. CRUTEM4 and HadSST3 are the land and ocean components of this overall dataset, respectively. These datasets have been developed by the Climatic Research Unit (University of East Anglia) in conjunction with the Hadley Centre (UK Met Office), apart from the sea surface temperature (SST) dataset which was developed solely by the UK Hadley Centre.

The chart shows area weighted Arctic (70-90 degrees N) monthly surface air temperature anomalies (HadCRUT4) since January 2000, in relation to the WMO normal period 1961-1990. The thin line shows the monthly temperature anomaly, while the thicker line shows the running 37-month (c. 3 year) average.

Diagram showing area weighted Antarctic (70-90 N) monthly surface air temperature anomalies (HadCRUT4) since January 2000, in relation to the WMO normal period 1961-1990. The thin line shows the monthly temperature anomaly, while the thicker line shows the running 37-month (c. 3 year) average.

For further information on a range of weather/climate matters see

https://sites.google.com/images/theweatherclimateeye/

https://sites.google.com/images/climatediceandthebutterfly/



Global Temperatures 1996 – June 2019

Weather Eye
with John Maunder

Global temperatures are compiled for various areas including global (land-ocean), global (meteorological stations), three latitude bands,

and hemispheric, by the Goddard Institute for Space Studies of NASA.

The graph shows the monthly mean global surface temperature anomaly from the base period 1951-1980, for the period 1996- June 2019.

For details see data.giss.nasa. (See graphs at the top right hand corner of the front web page and go to months)

The GISS Surface Temperature Analysis (GISTEMP) is an estimate of global surface temperature change. Graphs and tables are updated around the

middle of every month using current data files from NOAA GHCN v3 (meteorological stations), ERSST v4 (ocean areas), and SCAR (Antarctic stations),

combined as described in our December 2010 publication (Hansen et al. 2010). These updated files incorporate reports for the previous month and

also late reports and corrections for earlier month.

The basic GISS temperature analysis scheme was defined in the late 1970's when a method of estimating global temperature

change was needed for comparison with one-dimensional global climate models. The scheme was based on the finding that the correlation

of temperature change was reasonably strong for stations separated by up to 1200 km, especially at middle and high latitudes. This fact proved

sufficient to obtain useful estimates for global mean temperature changes.

The chart below shows that from 1997 to June 2019 there has been a small warming in the global monthly temperatures, and a relatively

warm period associated with the recent El Nino event.

For further information on a wide range of climate matters see https://sites.google.com/images/climatediceandthebutterfly/

The physicist Leo Szilard once announced to his friend Hans Bethe that he was thinking of keeping a diary: 'I don't intend to publish, I am merely going to record the facts for the information of God.' 'Don't you think God knows the facts?' Bethe asked. 'Yes' said Szilard. "He knows the facts, but he does not know THIS version of the facts' "(From Hans Christian von Baeyer, "Taming the Atom" (from the preface paragraph in "A Short History of Nearly Everything", by Bill Bryson, A Black Swan Book, 2004)



Solar Activity and the next Maunder Minimum

Weather Eye
with John Maunder

The ‘Maunder Minimum' is the name given to the period from 1645 to 1715 when the number of sunspots – ‘storms' on the sun – became almost zero.

The period is named after the solar astronomer Edward Walter Maunder (1851-1928), who was working at The Royal Observatory at Greenwich when he discovered the dearth of sunspots during this period.

During one 30-year period within the Maunder Minimum there were only about 50 sunspots compared with a more typical 40,000.

Maunder was a driving force in the foundation of the British Astronomical Association and a Fellow of the Royal Astronomical Society.

The sun was well observed during the period of the Maunder Minimum and this lack of sunspots is well documented.

Related image

This period of solar inactivity corresponded to a climatic period called the ‘Little Ice Age' when in Europe rivers that were normally ice-free, froze and snow fields remained at low altitudes throughout the year.

There is evidence the sun had similar periods of inactivity during the years 1100-1250 and 1460-1550.

Sunspots generally follow a cycle of about 11 years, but cycles have varied from eight-15 years.

The connection between solar activity and the earth's climate is an area of ongoing and sometimes controversial research.

An approaching Grand Solar Minimum is gaining “support” including NASA with their recent SC25 prediction — though they stay clear of the implications.

NASA’s forecast for the next solar cycle (25) reveals it will be the weakest of the last 200 years.

The maximum of this next cycle — measured in terms of sunspot number, a standard measure of solar activity level — could be 30 to 50% lower than the most recent one.

The agency’s results show that the next cycle will start in 2020 and reach its maximum in 2025:

The above chart and the following comment is from NASA’s official website (www.nasa.gov):

The new research was led by Irina Kitiashvili, a researcher with the Bay Area Environmental Research Institute at NASA’s Ames Research Center, in California’s Silicon Valley. It combined observations from two NASA space missions – the Solar and Heliospheric Observatory and the Solar Dynamics Observatory – with data collected since 1976 from the ground-based National Solar Observatory.One challenge for researchers working to predict the Sun’s activities is that scientists don’t yet completely understand the inner workings of our star. Plus, some factors that play out deep inside the Sun cannot be measured directly. They have to be estimated from measurements of related phenomena on the solar surface, like sunspots.

Time will tell whether the sun will once again go into another ‘Maunder Minimum' within the lifetime of the present generation, but if this happens we're likely to have a much colder climate for a few decades.

  1. sunspot number for most days during the last two months is zero.

A sunspot is a relatively dark, sharply defined region on the solar disc – marked by an umbra, dark area, which is 2000 degrees cooler than the effective photospheric temperature.

The average diameter of a sunspot is 4000 km, but they can exceed 200,000 km.

Sunspots are temporary phenomena on the Sun's photosphere that appear as spots darker than the surrounding areas. They are regions of reduced surface temperature caused by concentrations of magnetic field flux that inhibit convection. Sunspots usually appear in pairs of opposite magnetic polarity. Individual sunspots or groups of sunspots may last anywhere from a few days to a few months, but eventually decay.

The NASA solar physics website, and other websites such as the Royal Observatory of Belgium, include information on sunspot numbers, the ‘Maunder Minimum' and sunspot cycle predictions.

The sunspot index is updated monthly and available from 1749. The last time the monthly sunspot number was above 100 during the last 14 years was in September 2002, when the value was 110. February 2014 had a sunspot value of 102.

The last time the value was above 200 was in August 1990, when the value was 200.3..

*************************************

For further information on a range of weather.climate matters see: https://sites.google.com/images/climatediceandthebutterfly/

The physicist Leo Szilard once announced to his friend Hans Bethe that he was thinking of keeping a diary: 'I don't intend to publish, I am merely going to record the facts for the information of God.' 'Don't you think God knows the facts?' Bethe asked. 'Yes' said Szilard. "He knows the facts, but he does not know THIS version of the facts'

"(From Hans Christian von Baeyer, "Taming the Atom" (from the preface paragraph in "A Short History of Nearly Everything", by Bill Bryson, A Black Swan Book, 2004)



Tauranga June Average Afternoon Temperatures 1913-2019

Weather Eye
with John Maunder

Temperatures have been recorded in the Tauranga area at several sites during the last 107 years, including at the current Tauranga Airport site from June 1990.

The graph shows details of the average daily maximum temperatures, called simply ‘afternoon', for Tauranga for June from 1913-2019.

The long-term average afternoon temperature in June for Tauranga is 14.8 degrees Celsius.

The cool' June months were in 1972 with 13.0 degrees Celsius, 1936 with 13.2 degrees Celsius, and 1933 with 13.3 degrees Celsius.

The ‘warm' June months were in 2014 with 16.9 degrees Celsius, 1916 and 2011, both with 16.6 degrees Celsius, and June 2016 with 16.5 degrees C.

June 2014 had an average afternoon temperature of 16.9 degrees Celsius was the warmest June on record since observations were first made in 1913. The temperature in June 2019 was 15.5 degrees Celsius.

The graph of the average afternoon temperatures for June shows generally ‘normal' variations from June to June during the last 100 years.

But many of the last 20 June months since 1996 have been a little ‘warmer' than other June months since 1913.

From 1913 to 2019, there have been 15 June months with an average afternoon temperature of 15.6 degrees Celsius or more, and 12 June months with an average afternoon temperature of less than 13.9 degrees Celsius.

The ninth ‘warmest' June months on record, in chronological order, are: 1916, 1971, 1981, 1998, 1999, 2002, 2003, 2011, 2014, and 2016.

By contrast, the seventh ‘coolest' June months on record, in chronological order, are 1933, 1936, 1941, 1944,1969, 1972 and 1976.

The average afternoon temperature in June during the 51 year period 1914-1964 was 14.7 degrees Celsius, compared with 14.9 degrees Celsius for the 51 year period from 1965 to 2015.

For further information see https://sites.google.com/images/climatediceandthebutterfly/



Tauranga June Rainfalls 1898-2019

Weather Eye
with John Maunder

It is considered that the homogeneous rainfall series described here is a fair and true record of what the rainfall would have been if the current observation site (Tauranga Airport) had been used since 1898, with the understanding that although standard accepted methodologies have been used, any adjustments are only estimates of what would have occurred if the location of the rainfall records had always been in the same place with the same surroundings and the same or similar recording gauge.

The methodology use in adjusting the older sites to the current observing site is published in the ‘NZ Meteorological Service Miscellaneous Publication’ No 180 in 1984.

In terms of climate change (such as is it getting wetter or drier, or warmer or colder), the methodology used in computing an ‘official’ set of climate observations is very important, as otherwise erroneous conclusions may be drawn.

The graph shows the range of rainfalls from an extreme high of 381 mm in 1925 to a low of 19 mm in 1906. There is a small decrease in the overall June rainfalls during the last 50 years, from 1961-2010, from an average of 126 mm, compared with an average of 139 mm during the 50 years from 1911-1960.

The rainfall in June 2019 was 51 mm, which was was the twelfth driest June in 120 years of recorded observations.

Since 1898, there have been 17 June months with a rainfall of 200 mm or more, and 11 June months with rainfalls of 50 mm or less.

In chronological order the wettest 17 June months are: 1915, 1917, 1920, 1925, 1930, 1935, 1939, 1943, 1946, 1961, 1968, 1971, 1981, 1985, 1997, 2010, and 2014.

By contrast the driest June months in chronological order are: 1906, 1913, 1914, 1933, 1942, 1958, 1959, 1967, 2001, 2012, and 2015.

For further information on range of climate matters see: https://sites.google.com/images/climatediceandthebutterfly/



Tropospheric Temperatures 1979 to May 2019

Weather Eye
with John Maunder

The chart below shows that since 1979, when reliable satellite observations became available, there has been little change in the overall trend in the average tropospheric temperatures, apart from milder/warmer temperatures since about 1997, and two significant warm periods associated with the El Nino events in 1998 and 2015-16.

The latest global average temperatures of the troposphere updated to May 2019 - observed from US National Oceanic and Atmospheric Administration satellites – are computed by the University of Alabama at Huntsville in the United States. The data shows variations from the 30 year period 1981-2010.

Since 1979, NOAA satellites have been carrying instruments which measure the natural microwave thermal emissions from oxygen in the atmosphere. The intensity of the signals these microwave radiometers measure at different microwave frequencies is directly proportional to the temperature of different, deep layers of the atmosphere. Every month, researchers at the University of Alabama (Dr John Christy and Dr Roy Spencer) update global temperature datasets that represent the piecing together of the temperature data from a total of fourteen instruments flying on different satellites over the years.

The graph above represents the latest update; updates are usually made within the first week of every month. Contrary to some reports, the satellite measurements are not calibrated in any way with the global surface-based thermometer records of temperature. They instead use their own on-board precision redundant platinum resistance thermometers calibrated to a laboratory reference standard before launch.

The troposphere is the lowest layer of Earth's atmosphere.

It contains approximately 75 per cent of the atmosphere's mass and 99 per cent of its water vapour and aerosols.

The average depth of the troposphere is approximately 17 km in the middle latitudes.

The coolest months since 1979 were September 1984, with minus 0.49 degrees Celsius, and November 1984, with minus 0.42 degrees Celsius.

The warmest months were February 2016 with plus 0.83 degrees C, February and April 1998, both plus 0.76 degrees Celsius, and March 2016 plus 0.73 degrees, and April 2016 plus 0.73 degrees Celsius.

The chart shows the El Nino warming in the 1998 period, and 2015-16, and the Mount Pinatubo, volcanic cooling during 1992-1993.

****

In April 2015 Roy Spencer and his two colleagues published the following comment..

Version 6 of the UAH MSU/AMSU global satellite temperature dataset is by far the most extensive revision of the procedures and computer code we have ever produced in over 25 years of global temperature monitoring. The most significant changes from an end-user perspective are (1) a decrease in the global-average lower tropospheric (LT) temperature trend from +0.140 C/decade to +0.114 C/decade (December. 1978 through March. 2015); and (2) the geographic distribution of the LT trends, including higher spatial resolution. See the current webpage for further information.. https://www.drroyspencer.com/latest-global-temperatures/

For further information on a range of climate matters see: https://sites.google.com/images/climatediceandthebutterfly/

**********

The physicist Leo Szilard once announced to his friend Hans Bethe that he was thinking of keeping a diary: 'I don't intend to publish, I am merely going to record the facts for the information of God.' 'Don't you think God knows the facts?' Bethe asked. 'Yes' said Szilard. "He knows the facts, but he does not know THIS version of the facts'

"(From Hans Christian von Baeyer, "Taming the Atom" (from the preface paragraph in "A Short History of Nearly Everything", by Bill Bryson, A Black Swan Book, 2004)




Tauranga May Average Afternoon Temperatures 1913-2019

Weather Eye
with John Maunder

The average afternoon temperature in Tauranga in May 2019 was 18.7 degrees C, the fifth warmest on record.

Temperatures have been recorded in the Tauranga area at several sites during the last 100 years, including the current Tauranga Airport site from June 1990.

It's very common for areas, such as Tauranga, to have experienced different observation sites during the years – and the readings from the earlier sites have been adjusted to the present site using standard climatological procedures.

It's considered the temperature series described here is a fair and true record of what the temperature would have been if the current observation site (of Tauranga Airport) had been used throughout the period.

Traditionally, temperature observations have been recorded with a set of maximum and minimum temperature thermometers.

These record the daily maximum temperature – usually recorded in mid-afternoon – and daily minimum temperature – usually recorded just before dawn.

This analysis of temperatures for Tauranga is for the average daily maximum temperatures.

The graph shows details of the average daily maximum temperatures, called simply ‘afternoon', for Tauranga for May from 1913-2019. May 1964 is not included because of incomplete data.

The long-term average afternoon temperature in May for Tauranga is 16.9 degrees Celsius, ranging from the cool May months of 1936, 1940, and 1997 with an average afternoon temperature of 14.9 degrees Celsius, to the warm May months of 1916 and 2016 both with an average afternoon temperature of 19.3 degrees Celsius, May 2011 with 19.1 degrees Celsius, and May 2007 with 18.9 degrees Celsius.

The graph of the average afternoon temperatures for May shows generally normal variations from May to May.

However, the last 20 May months have been a little warmer than other May months since 1913.

From 1913 to 2019, there have been 15 May months with an average afternoon temperature of 18 degrees Celsius or more, and 11 May months with an average afternoon temperature of less than 16 degrees Celsius.

The value for May 2019 was 18.7 degrees Celsius, which is the fifth warmest on record.

The 15 warmest May months, in terms of afternoon temperatures, on record in chronological order are: 1916, 1928, 1938, 1950, 1999, 2000, 2003, 2005, 2007, 2010, 2011, 2013, 2014, 2016 and 2019.

In contrast, the 11 coolest May months, in terms of afternoon temperatures, on record in chronological order are: 1913, 1920, 1924, 1936, 1940, 1945, 1959, 1967, 1977, 1983, and 1992.

The average afternoon temperature in May during the 49-year period 1914-1962 was 16.7 degrees Celsius, compared with 17.1 degrees Celsius for the 49-year period from 1963-2011.

For further information see https://sites.google.com/images/climatediceandthebutterfly/



May Rainfalls for Tauranga 1898-2019

Weather Eye
with John Maunder

Rainfalls for the month of May have been recorded in Tauranga since 1898 – except for 1904, 1907, 1908, and 1909.

The graph shows the range of rainfalls from an extreme high of 634 mm in 2005 to a low of 13 mm in 2001. The rainfall for May 2019 was 47 mm.

The second wettest May was 1950, when 311 mm was recorded, and the second driest May was in 1918, when only 24 mm fell. The long-term average rainfall for Tauranga for May is 124 mm.

Apart from the exceptional rainfall of 634 mm in May 2005, the graph shows a small decrease in overall May rainfalls when the last two 50-year periods are compared.

Since 1898, there have been 14 May months with a rainfall of 200 mm or more. In chronological order, the wettest May months are: 1899, 1900, 1917, 1925, 1926, 1928, 1949, 1950, 1956, 1961, 1962, 1971, 2005, and 2010.

In terms of dry May months, there have been only nine May months with rainfall of less than 40 mm. In chronological order, the driest May months are: 1901, 1918, 1939, 1941, 1978, 1991, 1999, 2007, and 2014.

Of particular significance is the exceptional rainfall in May 2005. I estimated that such a rainfall is likely to occur in Tauranga only about twice in every 1000 years.

This suggests central government could have had a much more important role in financial implications of the floods, which affected many areas of Tauranga in May 2005.

For further information on the rainfalls in Tauranga see: https://sites.google.com/images/climatediceandthebutterfly/




Solar Activity and the Maunder Minimum

Weather Eye
with John Maunder

The ‘Maunder Minimum' is the name given to the period from 1645 to 1715 when the number of sunspots – ‘storms' on the sun – became almost zero.

The period is named after the solar astronomer Edward Walter Maunder (1851-1928), who was working at The Royal Observatory at Greenwich when he discovered the dearth of sunspots during this period.

During one 30-year period within the Maunder Minimum there were only about 50 sunspots compared with a more typical 40,000.

Maunder was a driving force in the foundation of the British Astronomical Association and a Fellow of the Royal Astronomical Society.

The sun was well observed during the period of the Maunder Minimum and this lack of sunspots is well documented.

This period of solar inactivity corresponded to a climatic period called the ‘Little Ice Age' when in Europe rivers that were normally ice-free, froze and snow fields remained at low altitudes throughout the year.

There is evidence the sun had similar periods of inactivity during the years 1100-1250 and 1460-1550.

Sunspots generally follow a cycle of about 11 years, but cycles have varied from eight-15 years.

The connection between solar activity and the earth's climate is an area of ongoing and sometimes controversial research.

Time will tell whether the sun will once again go into another ‘Maunder Minimum' within the lifetime of the present generation, but if this happens we're likely to have a much colder climate for a few decades.

The sunspot number for the last seven days ending May 26 2019 is zero.

A sunspot is a relatively dark, sharply defined region on the solar disc – marked by an umbra, dark area, which is 2000 degrees cooler than the effective photospheric temperature.

The average diameter of a sunspot is 4000 km, but they can exceed 200,000 km.

The NASA solar physics website, and other websites such as the Royal Observatory of Belgium, include information on sunspot numbers, the ‘Maunder Minimum' and sunspot cycle predictions.

The sunspot index is updated monthly and available from 1749. The last time the monthly sunspot number was above 100 during the last 14 years was in September 2002, when the value was 110. February 2014 had a sunspot value of 102.

The last time the value was above 200 was in August 1990, when the value was 200.3 – and there were no sunspots observed in September 2009.

*************************************

https://sites.google.com/images/climatediceandthebutterfly/



The Southern Oscillation Index

Weather Eye
with John Maunder

The Southern Oscillation Index (SOI) is a standardized index based on the observed sea level pressure differences between Tahiti and Darwin, Australia.

The SOI is a leading measure of the large-scale fluctuations in air pressure occurring between the western and eastern tropical Pacific (i.e., the state of the Southern Oscillation) during El Niño and La Niña episodes.

In general, smoothed time series of the SOI correspond very well with changes in ocean temperatures across the eastern tropical Pacific. The negative phase of the SOI represents below-normal air pressure at Tahiti and above-normal air pressure at Darwin. The positive phase of the SOI represents above-normal air pressure at Tahiti and below-normal air pressure at Darwin.

Prolonged periods of negative SOI values coincide with abnormally warm ocean waters across the eastern tropical Pacific typical of El Niño episodes. In contrast, prolonged periods of positive SOI values coincide with abnormally cold ocean waters across the eastern tropical Pacific typical of La Niña episodes. Sustained negative values of the SOI below −8 often indicate El Niño episodes.These negative values are usually accompanied by sustained warming of the central and eastern tropical Pacific Ocean, a decrease in the strength of the Pacific Trade Winds.

Sustained positive values of the SOI above +8 are typical of a La Niña episode.They are associated with stronger Pacific trade winds and warmer sea temperatures to the north of Australia. Waters in the central and eastern tropical Pacific Ocean become cooler during this time.

The graph below ( from the Australian Bureau of Meteorology, BOM) shows monthly values of the SOI from 1880 to May 2019..

International models surveyed by the Bureau indicate that sea surface temperatures in the tropical Pacific are likely to remain near El Niño thresholds until mid-winter, before cooling in late winter to spring. By August, two of the eight models are clearly at El Niño levels, with another two near El Niño thresholds.

El Nino and La Nina weather affects over New Zealand (source NIWA)

During El Niño, New Zealand tends to experience stronger or more frequent winds from the west in summer, typically leading to drought in east coast areas and more rain in the west.

In winter, the winds tend to be more from the south, bringing colder conditions to both the land and the surrounding ocean.

In spring and autumn south–westerly winds are more common.

La Niña events have different impacts on New Zealand's climate. More north–easterly winds are characteristic, which tend to bring moist, rainy conditions to the north–east of the North Island, and reduced rainfall to the south and south–west of the South Island.

Therefore, some areas, such as central Otago and South Canterbury, can experience drought in both El Niño and La Niña.

Warmer than normal temperatures typically occur over much of the country during La Niña, although there are regional and seasonal exceptions.

Although ENSO events have an important influence on New Zealand's climate, it accounts for less than 25 per cent of the year to year variance in seasonal rainfall and temperature at most New Zealand measurement sites.

***********************

The physicist Leo Szilard once announced to his friend Hans Bethe that he was thinking of keeping a diary: 'I don't intend to publish, I am merely going to record the facts for the information of God.' 'Don't you think God knows the facts?' Bethe asked. 'Yes' said Szilard. ‘He knows the facts, but he does not know THIS version of the facts'

"(From Hans Christian von Baeyer, "Taming the Atom" (from the preface paragraph in "A Short History of Nearly Everything", by Bill Bryson, A Black Swan Book, 2004)

For further information see: https://sites.google.com/images/climatediceandthebutterfly/



Tauranga Average Afternoon Temperatures April 1913-2019

Weather Eye
with John Maunder

Temperatures have been recorded in the Tauranga area at several sites during the last 100 years, including the current Tauranga Airport site from June 1990.

It's very common for areas such as Tauranga to have had different observation sites during the years – and the readings from the earlier sites have been adjusted to the present site using standard climatologically procedures.

The temperature series, as shown in the graph, are based on the data from the original observations from the various sites as available on the NIWA National Climate Database archive, with data from the sites prior to the Tauranga Airport site being adjusted, where appropriate, to temperatures which are likely to have been recorded at the current airport site.

Traditionally, temperature observations have been recorded with a set of maximum and minimum temperature thermometers.

These record the daily maximum temperature (usually recorded in mid-afternoon), and the daily minimum temperature (usually recorded just before dawn).

The graph shows details of the average daily maximum temperatures (called simply ‘afternoon'), for Tauranga for April from 1913-2019. Note April 1947 and 1964 are not included because of incomplete data.

The long-term average afternoon temperature in April for Tauranga for is 20.0 degrees Celsius, ranging from the cool April months of 1925, with an average afternoon temperature of 18.2 degrees Celsius, and 1923 with an average afternoon temperature of 18.3 degrees Celsius, to the warm April months of 1938 (22.2 degrees Celsius), and 1916 (22.1 degrees Celsius).

The graph of the average afternoon temperatures for April shows generally normal variations from April to April, but several of the last 20 April months have been a little warmer than other April months.

From 1913 to 2019, there have been 15 April months with an average afternoon temperature of 21.0 degrees Celsius or more, and eight April months with an average afternoon temperature of less than 19.0 degrees Celsius.

The value for April 2019 was 20.5 degrees Celsius,

The 15 warmest April months – in terms of afternoon temperatures – on record, in chronological order, are 1916, 1924, 1928, 1935, 1938, 1948, 1955, 1956, 1978, 1981, 2010, 2012, 2013, 2014, and 2016. In contrast, the eight coolest April months – in terms of afternoon temperatures – on record, in chronological order, are 1923, 1925, 1940, 1941, 1949, 1980, 1991 and 1992.

The average afternoon temperatures for Tauranga for the 50 years 1914-1962, and the 50-year period 1963-2011 are both 20.0 degrees Celsius

For further information see : https://sites.google.com/images/climatediceandthebutterfly/



Tauranga April Rainfalls 1898-2019

Weather Eye
with John Maunder

Monthly rainfalls for Tauranga have been recorded at several recording sites during the last 119 years.

From January 1898 to December 1904, the observation site was described as the Tauranga Harbour, from November 1904 to April 1907 the site was described as simply ‘Tauranga'.From January 1910 to December 1923 the site was Waikareao, in Otumoetai; from January 1924 to September 1940 the site was at 148 Waihi Rd, in Judea; from October 1940 to January 1941 the site was at Te Puna; and from February 1941 to now, the site is Tauranga Airport.

The methodology use in adjusting the older sites to the current observing site is published in the ‘NZ Meteorological Service Miscellaneous Publication' No 180 in 1984.

It is considered that the homogeneous rainfall series described here is a fair and true record of what the rainfall would have been if the current observation site (Tauranga Airport) had been used since 1898.

This should be coupled with the understanding that although standard accepted methodologies have been used, any adjustments are only estimates of what would have occurred if the location of the rainfall records had always been in the same place with the same surroundings and the same or similar recording gauge.

In terms of climate change (such as is it getting wetter or drier, or warmer or colder), the methodology used in computing an ‘official' set of climate observations is very important, as otherwise erroneous conclusions may be drawn.

April 2019 had a rainfall of 92 mm.

The graph shows the range of rainfalls from a high of 383 mm in 1911 to a low of 10 mm in 1958.

The second wettest April was 1948, when 333 mm was recorded; and the second driest was April 2010 with only 12 mm.

The long-term average rainfall for Tauranga for April is 120 mm.

Since 1898, there have been 11 April months with a rainfall of 250 mm or more.

In chronological order, the wettest April months are: 1911, 1923, 1935, 1938, 1948, 1959, 1995, 2000, 2001, 2013, and 2017.

In terms of dry April months, there have been nine months with rainfall of 30 mm or less.

In chronological order, the driest April months are: 1898, 1910, 1913, 1919, 1958, 1979, 1984, 2005, and 2010.

For further information see: https://sites.google.com/images/climatediceandthebutterfly/




Climate Change and Villach : What is the connection?

Weather Eye
with John Maunder

Among the many climate science meetings I have attended, the most significant, at least in term of climate change is concerned, is my involvement in the UN sponsored International Conference held in the beautiful town Villach, in Austria in October 1985.

One hundred experts from 30 countries attended the meeting (in contrast to ten to twenty thousand who now attend such meetings), and I was privileged to be the only New Zealander invited.

We were all there as experts - and not representing our respective organisations - in various fields of science, endeavouring to do the best we could in looking at the complexities of climate science.

Among the principal findings of this conference was that "while other factors, such as aerosol concentration, changes in solar energy input, and changes in vegetation, may also influence climate, the greenhouse gases are likely to be the most important cause of climate change over the next century”.

At that time, even though I was partly responsible for the writing of the above paragraph, I along with a few of my colleagues, had some misgivings about this phrase, and were somewhat surprised that within a year ‘human-induced global warming' caught the imagination of much of the world.

Indeed today, not a day goes by without some mention of ‘global warming', climate change, emission trading schemes, etc, all terms which up until 1980 were the preserve of academic text books.

Despite this concern, a colleague of mine from Australia, Bill Kininmonth, who in 2004 wrote a book called "Climate Change - A Natural Hazard" has mentioned to me on several occasions that I have changed from being the ‘gamekeeper' and become the ‘poacher'.

Whether that is true is a matter of opinion. However, irrespective of my personal views on the matter, it is clear that there are two main views held by climate scientists and others on the subject of global warming and climate change.

First, those who are mainly involved in the Intergovernmental Panel on Climate Change and many or most government scientists, plus others, such as Al Gore, and many politicians and most journalists who consider that man, including domestic animals, is the prime cause of recent changes in the climate;

Second, those - in the main some university scientists, many retired climatologists, and a minority of politicians and journalists, who consider that nature is the main cause of changes in the climate.

Thirty years ago, it was unconceivable that the New Zealand Government would have a Minister of Climate Change; indeed back then, as weather forecasters and climatologists we just got on with our job of making the best possible weather forecast and providing the best climate advice to all those who requested information, without guidance or interference from the Government of the day. How things have changed!

**********

https://sites.google.com/images/climatediceandthebutterfly/

The physicist Leo Szilard once announced to his friend Hans Bethe that he was thinking of keeping a diary: 'I don't intend to publish, I am merely going to record the facts for the information of God.' 'Don't you think God knows the facts?' Bethe asked. 'Yes' said Szilard. ‘He knows the facts, but he does not know THIS version of the facts'

"(From Hans Christian von Baeyer, "Taming the Atom" (from the preface paragraph in "A Short History of Nearly Everything", by Bill Bryson, A Black Swan Book, 2004)



Tropospheric Temperatures 1979 to March 2019

Weather Eye
with John Maunder

The chart below shows that since 1979, when reliable satellite observations became available, there has been little overall trend in the average tropospheric temperatures, apart from milder/warmer temperatures since about 1997, and two significant warm periods associated with the El Nino events in 1998 and 2015-16.

The latest global average temperatures of the troposphere updated to March 2019 - observed from US National Oceanic and Atmospheric Administration satellites – are computed by the University of Alabama at Huntsville in the United States. The data shows variations from the 30 year period 1981-2010.

Since 1979, NOAA satellites have been carrying instruments which measure the natural microwave thermal emissions from oxygen in the atmosphere. The intensity of the signals these microwave radiometers measure at different microwave frequencies is directly proportional to the temperature of different, deep layers of the atmosphere. Every month, researchers at the University of Alabama (Dr John Christy and Dr Roy Spencer) update global temperature datasets that represent the piecing together of the temperature data from a total of fourteen instruments flying on different satellites over the years.

The graph above represents the latest update; updates are usually made within the first week of every month. Contrary to some reports, the satellite measurements are not calibrated in any way with the global surface-based thermometer records of temperature. They instead use their own on-board precision redundant platinum resistance thermometers calibrated to a laboratory reference standard before launch.

The troposphere is the lowest layer of Earth's atmosphere.

It contains approximately 75 per cent of the atmosphere's mass and 99 per cent of its water vapour and aerosols.

The average depth of the troposphere is approximately 17 km in the middle latitudes.

The coolest months since 1979 were September 1984, with minus 0.49 degrees Celsius, and November 1984, with minus 0.42 degrees Celsius.

The warmest months were February 2016 with plus 0.83 degrees C, February and April 1998, both plus 0.76 degrees Celsius, and March 2016 plus 0.73 degrees, and April 2016 plus 0.73 degrees Celsius.

The chart shows the El Nino warming in the 1998 period, and 2015-16, and the Mount Pinatubo, volcanic cooling during 1992-1993.

For for information see: https://sites.google.com/images/climatediceandthebutterfly

The physicist Leo Szilard once announced to his friend Hans Bethe that he was thinking of keeping a diary: 'I don't intend to publish, I am merely going to record the facts for the information of God.' 'Don't you think God knows the facts?' Bethe asked. 'Yes' said Szilard. "He knows the facts, but he does not know THIS version of the facts'


"(From Hans Christian von Baeyer, "Taming the Atom" (from the preface paragraph in "A Short History of Nearly Everything", by Bill Bryson, A Black Swan Book, 2004)


WMO Day March 23 2019

Weather Eye
with John Maunder

The World Meteorological Organisation WMO), is the successor of the International Meteorological Organisation (IMO) which was created in 1873.

Its fundamental mission is to support the countries of the world in providing meteorological and hydrological services to protect life and property from natural disasters related to weather, climate, and water, to safeguard the environment, and to contribute to sustainable development.

This cannot happen without the necessary observations, research and operations that develop the understanding and knowledge of weather and climate.

Since 1961, World Meteorological Day has commemorated the coming into force on 23 March 1950 of the Convention establishing the World Meteorological Organization (WMO) and the essential contribution that National Meteorological and Hydrological Services make to the safety and well-being of society. Each year, the celebrations focus on a theme of topical interest.

The theme of World Meteorological Day 2018 was “Weather-ready, climate-smart”, which looked at the growing hazards – such as tropical cyclones, storm surges, heavy rains, heat waves, and droughts – that are threatening global populations. It is one of WMO’s top priorities to protect lives, livelihoods, and property from the risks related to weather, climate and water events.

World Meteorological Day 2019 will be looking at “The Sun, the Earth and the Weather”.

The Sun delivers the energy that powers all life on Earth. It drives the weather, ocean currents and daily activities. It is the inspiration for music, photography and art.

The theme for the 2015 World Meteorological Day “Climate knowledge for climate action,” provided an opportunity to take stock of the climate knowledge built during the last decades, as an essential base to support the path towards more ambitious action to address climate change and climate variability.

The NZ MetService communications meteorologist Lisa Murray says that “Understanding Clouds” the theme of World Meteorological Day 2018, was to highlight the enormous importance of clouds for weather climate and water.

It also marks the launch of the new edition of the International Cloud Atlas, the single authoritative and most comprehensive reference for identifying clouds and a treasure trove of hundreds of images of clouds, including a few newly-classified cloud types.

The structure of the WMO which has headquarters in Geneva involves the Congress, the Executive Council, and eight Technical Commissions.

The World Meteorological Congress, the supreme body of the Organisation, assembles delegates of Members (countries) once every four years to determine general policies for the fulfilment of the purposes of the Organisation; to consider membership of the Organisation; to determine the general, technical, financial and staff regulations; to establish and coordinate the activities of constituent bodies of the Organisation; to approve long-term plans and budget for the following financial period; to elect the President and Presidents of the Organisation and members of the Executive Council; and to appoint the Secretary-General.

The Executive Council is the executive body of the Organisation, which meets annually, implements decisions of Congress, coordinates the programmes, examines the utilization of budgetary resources, considers and takes action on recommendations of regional associations and technical commissions and guides their work programme, provides technical information, counsel and assistance in the fields of activity of the Organisation and studies and takes action on matters affecting international meteorology and related activities.

The Council is composed of 37 directors of National Meteorological or Hydrometeorological Services, serving in an individual capacity as representatives of the Organisation and not as representatives of particular Members thereof. They include the President and three Vice-Presidents who are elected by Congress, and the presidents of the six regional associations. The remaining 27 members are elected by Congress.

There are also eight Technical Commissions which are composed of experts designated by Members and are responsible for studying meteorological, climatological, and hydrological operational systems, applications and research.

They establish methodology and procedures and make recommendations to the Executive Council and the Congress. The Technical Commissions usually meet once every four years, when they elect a President* and Vice-President.

*From 1989 to 1996, I was President of one of Technical Commissions, namely the “Commission for Climatology” .

In addition, three others from New Zealand have been Presidents of WMO Technical Commissions, Dr Jim Salinger (Commission for Agricultural Meteorology), Dr Neil Gordon ( Commission for Aeronautical Meteorology), and Dr John Gabites (Commission for Atmospheric Sciences).

For further information see: https://sites.google.com/images/climatediceandthebutterfly




Tauranga March Average Afternoon Temperatures 1913-2019

Weather Eye
with John Maunder

Temperatures have been recorded in the Tauranga area at several sites during the last 100 years including the current Tauranga Airport site from June 1990.

The graph shows details of the average daily maximum temperatures, called simply ‘afternoon', for Tauranga for the months of March from 1913-2019.

March 1947 is not included because of incomplete data.

The average daily maximum temperature for March 2019 was 23.9 degrees Celsius, the eighth warmest on record.

The long-term average afternoon temperature in March for Tauranga is 22.5 degrees Celsius, ranging from the cool March months of 1960 with an average afternoon temperature of 20.4 degrees Celsius, and 1940 with an average afternoon temperature of 20.8 degrees Celsius, to the warm March months of 1916 (24.7 degrees Celsius), and 1938 and 1968 (24.6 degrees Celsius).

The graph of the average afternoon temperatures for March shows generally normal variations from March to March but with some warming over the last 20 years .

From 1913 to 2019, there have been twelve March months with an average afternoon temperature of 23.7 degrees Celsius or more, and 13 March months with an average afternoon temperature of 21.5 degrees Celsius or less.

The nine warmest March months – in terms of average afternoon temperatures on record –in chronological order are: 1913, 1914,1916, 1938, 1968, 2005, 2010, 2013, and 2019..

In contrast the 13 coolest March months – in terms of afternoon temperatures on record –in chronological order are: 1923, 1934,1936, 1940, 1944, 1945, 1949, 1960, 1974, 1976, 1992, 1993 and 1998.

The average afternoon temperature for March for the 48 years from 1914-1962 was 22.4 degrees Celsius, compared with an average of 22.6 degrees Celsius for the 48 years from 1963-2011.

For further information see the following textbooks books (all available at specialised libraries)

"The Value of the Weather" (1970), "The Uncertainty Business - Risks and Opportunities in Weather and Climate" (1986), "The Human Impact of Climate Uncertainty - Weather Information, Economic Planning, and Business Management " (1989), all by W.J.Maunder



Tauranga March Rainfalls 1898-2019

Weather Eye
with John Maunder

Rainfalls for the month of March have been recorded in Tauranga since 1898 – except for 1904, 1908 and 1909.

This graph below shows the range of rainfalls from a high of 504 mm in 1979, to a low of 5 mm in 1943.

The second wettest March was in 1972, when 318 mm was recorded, and two March months – 1921 and 2010 – recorded 14 mm.

The long-term average rainfall for Tauranga for March is 109 mm. The rainfall for March 2019 was 53 mm.

The graph shows no significant overall trend in rainfalls in March during the last 120 years, apart from a small increase in the average rainfall for the 50 years ending in 1960 of 103 mm, compared with 117 mm in the 50 years to 2010.

Since 1898, there have been eleven March months with a rainfall of 200 mm or more, and eleven March months with a rainfall of 30 mm or less.

The wettest March months in chronological order are: 1902,1918,1922,1935,1941,1944,1957,1962,1972,1979 and 1987.

The driest March months in chronological order are: 1903,1905,1921,1943,1951,1952,1953,1969, 2004, 2010 and 2013.

For further information see the following textbooks books (all available at specialised libraries)

"The Value of the Weather" (1970), "The Uncertainty Business - Risks and Opportunities in Weather and Climate" (1986), "The Human Impact of Climate Uncertainty - Weather Information, Economic Planning, and Business Management " (1989),all by W.J.Maunder



Tauranga February average afternoon temperatures 1913-2019

Weather Eye
with John Maunder

Temperatures have been recorded in the Tauranga area at several sites during the last 100 years, including the current Tauranga Airport site from June 1990.

It's very common for areas such as Tauranga to have had different observation sites during the years; and the readings from the earlier sites have been adjusted to the present site using ‘standard climatological procedures'.

It's considered the temperature series described here is a fair and true record of what the temperature would have been if the current observation site (Tauranga Airport) had been used throughout the period.

It's important to note that in considering ‘climate change', the methodology used in computing an 'official' set of climate observations is very important – as otherwise erroneous conclusions may be drawn.

Traditionally, temperature observations have been recorded with a set of maximum and minimum temperature thermometers. These record the daily maximum temperature (usually recorded in mid-afternoon), and daily minimum temperature (usually recorded just before dawn).

This analysis of February temperatures for Tauranga is for the average daily maximum temperatures.

The graph above shows details of the average daily maximum temperatures (called simply ‘afternoon'), for Tauranga for February from 1913-2019

.The long-term average afternoon temperature in February for Tauranga is 23.8 degrees Celsius, ranging from the ‘cool' February months of 1934, with an average afternoon temperature of 21.6 degrees C , and 1921 with an average afternoon temperature of 21.8 degrees Celsius, to the ‘warm' February months of 1916 (26.4 degrees Celsius), 1998 (26.2 degrees Celsius), 2011 (26.0 degrees Celsius), and 2019 (26.0 degrees C).

The graph of the average afternoon temperatures for February shows generally 'normal' variations from February to February.

The average afternoon February temperature for the 49 years from 1963-2011 of 24.0 degrees Celsius; this is just 0.3 degrees Celsius higher than the average afternoon February temperature for the 49 years from 1914-1962.

From 1914 to 2019, there have been seven February months with an average afternoon temperature of 25.5 degrees Celsius or more, and six February months with an average afternoon temperature of 22.5 degrees Celsius or less.

The average afternoon temperature for February 2019 was 26.0 degrees Celsius.

The seven ‘warmest' February months (in terms of afternoon temperatures) on record, in chronological order, are: 1916, 1928, 1954, 1955, 1998, 2011, 2019.

In contrast the six ‘coolest' February months (in terms of afternoon temperatures) on record, in chronological order, are: 1921, 1931, 1934, 1940, 1976, and 2004.

For further information see the following textbooks books (all available at specialised libraries)

"The Value of the Weather" (1970), "The Uncertainty Business - Risks and Opportunities in Weather and Climate" (1986), "The Human Impact of Climate Uncertainty - Weather Information, Economic Planning, and Business Management " (1989), all by W.J.Maunder



Sunspots and the Sun

Weather Eye
with John Maunder

A sunspot is a relatively dark, sharply defined region on the solar disc - marked by an umbra (dark area) which is 2000 degrees Celsius cooler than the effective photosphere temperature. The average diameter of a sunspot is 4000 km, but can exceed 200,000 km.

The NASA Solar Physics website (and other web sites such as the Royal Observatory of Belgium) includes information on sunspot numbers, the ‘Maunder Minimum', and sunspot cycle predictions. The sunspot index is updated monthly and available from 1749. The last time the monthly sunspot number was above 100 for any significant period of time was September 2002 when the value was 109.6, and the last time the value was above 200 was in August 1990 when the value was 200.3.

The peak of latest solar cycle Number 24 was reached in April 2014, with a maximum of the 13-month smoothed sunspot number at 81.8. Since then, solar activity has steadily declined. The monthly mean sunspot number is now less than ten.

As this late maximum comes more than 5 years after the preceding minimum in December 2008, cycle 24 has now entered its long declining phase, as none of the past observed cycles had longer delays between minimum and maximum. Therefore, the average solar activity should progressively decrease towards a minimum around 2019.

We are currently over eights years into solar cycle 24. This the smallest sunspot cycle since solar cycle 14 which had a maximum of 64.2 in February of 1906.

Spotless Days

Since mid-2016, the Sun has occasionally been devoid of sunspots. These spotless disks will gradually become a familiar feature as the solar cycle is heading for its next minimum, currently expected by the end of this decade. The number of spotless days can vary significantly from one solar cycle transit to another. For example, during the previous minimum (around 2008), no less than 817 spotless days were recorded, whereas the minimum period leading into solar cycle 23 (around 1996) counted only 309 such blemishless days.

As the current solar cycle 24 will gradually give way to the new solar cycle 25, several consecutive days and even weeks without sunspots will become the norm. In order to have an idea on the number of spotless days, and how these numbers compare to past solar cycles, the SILSO web site has created a “Spotless Days page”. This page contains graphs and tables on the accumulated number of spotless days, stretches of spotless days, and comparisons to other solar cycles – all supplemented with a word of explanation.

The previous minimum surprised scientists and solar observers by being the deepest in nearly 90 years. Will the upcoming solar cycle minimum show as many spotless days, or will solar cycle 25 take off much faster than expected? The “Spotless Days page” will provide you with a front-row seat on the current status of the solar cycle minimum and the number of spotless days. Enjoy! Perhaps a new “Maunder Minimum” era is upon is!

**********************************

The physicist Leo Szilard once announced to his friend Hans Bethe that he was thinking of keeping a diary: 'I don't intend to publish, I am merely going to record the facts for the information of God.' 'Don't you think God knows the facts?' Bethe asked. 'Yes' said Szilard. ‘He knows the facts, but he does not know THIS version of the facts'

"(From Hans Christian von Baeyer, "Taming the Atom" (from the preface paragraph in "A Short History of Nearly Everything", by Bill Bryson, A Black Swan Book, 2004)

For further information see: https://sites.google.com/images/climatediceandthebutterfly/

**********************************



Tropospheric Temperatures 1979 to January 2019

Weather Eye
with John Maunder

The chart below shows that since 1979, when reliable satellite observations became available, there has been little overall trend in the average tropospheric temperatures, apart from milder/warmer temperatures since about 1997, and two significant warm periods associated with the El Nino events in 1998 and 2015-16.

The latest global average temperatures of the troposphere updated to October 2018 - observed from US National Oceanic and Atmospheric Administration satellites – are computed by the University of Alabama at Huntsville in the United States. The data shows variations from the 30 year period 1981-2010.

Since 1979, NOAA satellites have been carrying instruments which measure the natural microwave thermal emissions from oxygen in the atmosphere. The intensity of the signals these microwave radiometers measure at different microwave frequencies is directly proportional to the temperature of different, deep layers of the atmosphere. Every month, researchers at the University of Alabama (Dr John Christy and Dr Roy Spencer) update global temperature datasets that represent the piecing together of the temperature data from a total of fourteen instruments flying on different satellites over the years.

The graph above represents the latest update; updates are usually made within the first week of every month. Contrary to some reports, the satellite measurements are not calibrated in any way with the global surface-based thermometer records of temperature. They instead use their own on-board precision redundant platinum resistance thermometers calibrated to a laboratory reference standard before launch.

The troposphere is the lowest layer of Earth's atmosphere.

It contains approximately 75 per cent of the atmosphere's mass and 99 per cent of its water vapour and aerosols.

The average depth of the troposphere is approximately 17 km in the middle latitudes.

The latest data for December is +0.25 degrees C.

The coolest months since 1979 were September 1984, with minus 0.49 degrees Celsius, and November 1984, with minus 0.42 degrees Celsius.

The warmest months were February 2016 with plus 0.83 degrees C, February and April 1998, both plus 0.76 degrees Celsius, and March 2016 plus 0.73 degrees, and April 2016 plus 0.73 degrees Celsius.

The chart shows the El Nino warming in the 1998 period, and 2015-16, and the Mount Pinatubo, volcanic cooling during 1992-1993.

****************************

The physicist Leo Szilard once announced to his friend Hans Bethe that he was thinking of keeping a diary: 'I don't intend to publish, I am merely going to record the facts for the information of God.' 'Don't you think God knows the facts?' Bethe asked. 'Yes' said Szilard. ‘He knows the facts, but he does not know THIS version of the facts'

"(From Hans Christian von Baeyer, "Taming the Atom" (from the preface paragraph in "A Short History of Nearly Everything", by Bill Bryson, A Black Swan Book, 2004)

For further information see: https://sites.google.com/images/climatediceandthebutterfly/



Global Temperatures 1996 – January 2019

Weather Eye
with John Maunder

Global temperatures are compiled for various areas including global (land-ocean), global (meteorological stations), three latitude bands, and hemispheric, by the Goddard Institute for Space Studies of NASA.

The graph shows the monthly mean global surface temperature anomaly from the base period 1951-1980, for the period 1996- January 2019.

For details see data.giss.nasa. (See graphs at the top right hand corner of the front web page and go to months)

The GISS Surface Temperature Analysis (GISTEMP) is an estimate of global surface temperature change.

Graphs and tables are updated around the middle of every month using current data files from NOAA GHCN v3 (meteorological stations), ERSST v4 (ocean areas), and SCAR (Antarctic stations), combined as described in our December 2010 publication (Hansen et al. 2010).

These updated files incorporate reports for the previous month and also late reports and corrections for earlier month.

The basic GISS temperature analysis scheme was defined in the late 1970's by James Hansen when a method of estimating global temperature change was needed for comparison with one-dimensional global climate models.

The scheme was based on the finding that the correlation of temperature change was reasonably strong for stations separated by up to 1200 km, especially at middle and high latitudes. This fact proved sufficient to obtain useful estimates for global mean temperature changes.

he chart below shows that from 1997 to January 2019 there has been a small warming in the global monthly temperatures, and a relatively warm period associated with the recent 2015-2017 El Nino events.

For further information on a wide range of climate matters see   :https://sites.google.com/images/climatediceandthebutterfly




 

 

 





Tauranga January Average Afternoon Temperatures 1914-2019

Weather Eye
with John Maunder

Temperatures have been recorded in the Tauranga area at several sites during the last 100 years, including the current Tauranga Airport site from June 1990.

The graph above shows details of the average daily maximum temperatures (called simply ‘afternoon') for Tauranga for January from 1914-2019.

The long-term average afternoon temperature in January for Tauranga is 23.8 degrees Celsius, ranging from the cool January months of 1920, with 21.6 degrees Celsius, and 1939 with 21.8 degrees Celsius, to the very warm January months of 1935, with 27.7 degrees Celsius, and January 2019 with 26.7 degrees Celsius.

The average afternoon temperature in January 2019 was 26.7 degrees Celsius, the second warmest January on record.

The average January afternoon temperature during the 50 years from 1963 to 2011 of 23.8 degrees Celsius, is the same average recorded in the 50 year period from 1914 to 1962.

From 1914 to 2019, there have been ten January months with an average afternoon temperature of 25.3 degrees Celsius or higher, and seven January months with an average afternoon temperature of 22.5 degrees Celsius or lower.

The ten warmest January months (in terms of afternoon temperatures), on record, in chronological order, are 1914, 1915, 1935, 1970, 1957, 1999, 2009, 2015, 2018, and 2019.

The seven coolest January months (in terms of early morning temperatures) in order, are 1918,1920,1922,1925,1930,1939, and 1980.

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For further information see: https://sites.google.com/site/climatediceandthebutterfly


Tauranga January Rainfalls 1898-2019

Weather Eye
with John Maunder

The graph shows the range of Tauranga's January rainfalls from 1898-2019, varied from an extreme high of 532 mm in 1907 to a low of only 1 mm in 1928.

The second wettest January was 2011, when 347 mm was recorded; and the second driest January was in 2013, when only 4 mm fell.

The long-term average rainfall for Tauranga for January is 89 mm.

The rainfall for January 2019 was 16 mm. The graph of the January rainfall shows generally normal variations from year to year.

Since 1898 there have been eight January months with a rainfall of 180 mm or more, with two such wet January months, 1940 and 1941, being consecutive.

Fourteen January months have experienced rainfalls of less than 20 mm, with two such dry January months, 1978 and 1979, being consecutive.

In chronological order, the eighth wettest January months are 1907 with 532 mm, 1920 with 196 mm, 1940 with 254 mm, 1941 with 245 mm, 1951 with 204 mm, 1965 with 183 mm, 1989 with 268 mm, and 2011 with 347 mm.

In contrast, the seventh driest January months in chronological order are 1900 with 8 mm, 1928 with 1 mm, 1944 with 10 mm, 1957 with 8 mm, 1988 with 9 mm, 2013 with 4 mm, and 2015 with 8 mm.

for further information see: https://sites.google.com/images/climatediceandthebutterfly/


 https://www.sunlive.co.nz/blogs/13000-tauranga-january-rainfalls-18982019.html


Groundhog Day February 2, 2019 .... Those Climate Predictions

Weather Eye
with John Maunder

Groundhog Day, February 2, is a popular tradition in the United States. It is also a legend that traverses many centuries, its origins clouded in the mists of time with ethnic cultures and animals awakening on specific dates.

Media reports for February 2, 2019 said that the famous groundhog in Pennsylvania, Punxsutawney did not see its shadow and that means that in at least in Pennsylvania the winter is nearly over.

CNN report that thousands of people gathered Saturday at Gobbler's Knob in Punxsutawney, Pennsylvania, to watch a famous groundhog deliver his highly anticipated forecast.

Punxsutawney Phil emerged from his burrow around 7:30 a.m. and did not see his shadow, predicting an early spring for us all.

A member of Phil's Inner Circle read from the groundhog's prediction scroll to the cheers and applause from the crowd.

"Faithful followers, there is no shadow of me and a beautiful spring it shall be”.

Myths such as this tie our present to the distant past, when nature did indeed influence our lives –and to many, nature is still influencing out lives. It is also the day the Groundhog comes out of his hole after a long winter sleep to look for his shadow.

Tradition has it if the groundhog sees his shadow, he regards it as an omen of six more weeks of bad weather and returns to his hole. But, if the day is cloudy and, hence, shadow less, he takes it as a sign of spring and stays above ground.

The groundhog tradition stems from similar beliefs associated with Candlemas Day and the days of early Christians in Europe. It marked a milestone in the winter and the weather that day was important. And according to an old English Song:

“If Candlemas be fair and bright,

Come, winter, have another flight;

If Candlemas brings clouds and rain,

Go winter, and come not again.”

The Roman legions, supposedly brought this tradition to the Teutons, or Germans, who picked it up and concluded that if the sun made an appearance on Candlemas Day, an animal, the hedgehog, would cast a shadow; thus predicting six more weeks of bad weather, which they interpolated as the length of the ‘Second Winter'.

In the United States, Pennsylvania's earliest settlers were Germans and they found groundhogs in profusion in many parts of the State. They determined the groundhog, resembling the European hedgehog, was a most intelligent and sensible animal; and therefore decided if the sun did appear on February 2nd, this wise animal would see its shadow and hurry back into its underground home for another six weeks of winter.

The the Germans thus recited:

“For as the sun shines on Candlemas Day,

So far will the snow swirl until the May”.

This passage may be the one most closely-represented by the first Punxsutawney Groundhog Day observances because there were references to the length of shadows in early Groundhog Day predictions. The ancient Candlemas legend and similar belief continue to be recognised annually on February 2, due to the efforts of the Punxsutawney Groundhog Club.

Early observances of Phil's (the Groundhog) predictions were conducted privately in the wooded areas around the town. Today, the celebration today sees thousands of visitors from worldwide as revellers await Phil's appearance with national-wide TV coverage.

The ‘Punxsutawney Spirit' newspaper is credited with printing the news of the first observance in 1886 when it states that up to the time of going to press the beast has not seen his shadow.”

In 1993, Columbia Pictures released the movie Groundhog Day starring Bill Murray. In the years following the release of the movie, record crowds numbering as high as 30,000 have visited Gobbler's Knob in Punxsutawney.

Punxsutawney Phil gets his longevity from drinking “groundhog punch”. One sip, which is administered every summer at the Groundhog Picnic, gives him seven more years of life.

Contrary to media explanations , Phil's forecasts are not made in advance by the Inner Circle. Indeed, only after Phil emerges from his burrow on February 2 does he speaks to the Groundhog Club President in “Groundhog Language”. Phil's proclamation is then translated for the world to hear.

The US National Weather Service notes that the Punxsutawney Groundhog Day predictions have been right 10 times and wrong 15 times in recent years. They comment that “Unfortunately ,the famous groundhog has shown no talent for predicting the arrival of spring, especially in recent years, and Phil's competitor groundhogs across the Nation fared no better.”

However, who knows what the future groundhogs will forecast.

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The physicist Leo Szilard once announced to his friend Hans Bethe that he was thinking of keeping a diary: 'I don't intend to publish, I am merely going to record the facts for the information of God.' 'Don't you think God knows the facts?' Bethe asked. 'Yes' said Szilard. ‘He knows the facts, but he does not know THIS version of the facts'

"(From Hans Christian von Baeyer, "Taming the Atom" (from the preface paragraph in "A Short History of Nearly Everything", by Bill Bryson, A Black Swan Book, 2004)


For further information see: https://sites.google.com/site/theweatherclimateeye/




Tauranga Annual Rainfalls 1898-2018

Weather Eye
with John Maunder

Monthly rainfalls for Tauranga have been recorded at several recording sites during the last 121 years.

From January 1898 to December 1904, the observation site was described as the Tauranga Harbour, from November 1904 to April 1907 the site was described as simply ‘Tauranga'. From January 1910 to December 1923 the site was Waikareao, in Otumoetai; from January 1924 to September 1940 the site was at 148 Waihi Rd, in Judea; from October 1940 to January 1941 the site was at Te Puna; and from February 1941 to now, the site is Tauranga Airport.

The methodology use in adjusting the older sites to the current observing site is published in the ‘NZ Meteorological Service Miscellaneous Publication' No 180 in 1984.

It is considered that the homogeneous rainfall series described here is a fair and true record of what the rainfall would have been if the current observation site (Tauranga Airport) had been used since 1898.

This should be coupled with the understanding that although standard accepted methodologies have been used, any adjustments are only estimates of what would have occurred if the location of the rainfall records had always been in the same place with the same surroundings and the same or similar recording gauge.

In terms of climate change (such as is it getting wetter or drier, or warmer or colder), the methodology used in computing an ‘official' set of climate observations is very important, as otherwise erroneous conclusions may be drawn.

The long-term average rainfall for Tauranga for the calendar year is 1300 mm, ranging from a low of 747 mm in 2002, to a high of 2049 mm in 1962.

For comparison, the rainfall for the last year, 2018, was 1515 mm.

Since 1898, there have been only four years with a rainfall of less than 900 mm, they are 1914, 1982, 1993, and 2002.

And there's only been four years with a rainfall of more than 1800 mm; they are the two consecutive years of 1916 and 1917, plus 1938 and 1962.

The ten wettest years on record are: 1962 which had 2049 mm or 57 per cent above of the long-term average, while 1917 had 1985 mm or 52 per cent above average. Also, 1916 had 1941 mm or 49 per cent above average, plus 1938 (1817 mm), 1920 (1789 mm), 1956 (1777 mm), 1979 (1730 mm), 2011 (1696 mm), 2005 (1682 mm), and 1935 (1670 mm).

In chronological order, these wettest years occurred in 1916, 1917, 1920, 1935, 1938, 1956, 1962, 1979, 2005 and 2011.

In contrast, the 10 driest years on record are: 2002 (747 mm or 48 per cent below the long-term average), 1914 (773 mm or 41 per cent below the long-term average), 1982 (842 mm or 36 per cent below the long-term average), plus 1993 (863 mm), 1906 (950 mm), 1919 (962 mm), 1997 (978 mm), 1973 (989 mm), 1986 (991 mm), and 1999 (1002 mm).

In chronological order, these driest years occurred in 1906, 1914, 1919, 1973, 1982, 1986, 1993, 1997, 1999, and 2002.

The average rainfall in Tauranga for the 50 years 1911-60 was 1365 mm, compared with the average rainfall for the 50 years 1961-2010 of 1263 mm.

*******

The physicist Leo Szilard once announced to his friend Hans Bethe that he was thinking of keeping a diary: 'I don't intend to publish, I am merely going to record the facts for the information of God.' 'Don't you think God knows the facts?' Bethe asked. 'Yes' said Szilard. ‘He knows the facts, but he does not know THIS version of the facts'

"(From Hans Christian von Baeyer, "Taming the Atom" (from the preface paragraph in "A Short History of Nearly Everything", by Bill Bryson, A Black Swan Book, 2004)

For further information see: https://sites.google.com/site/climatediceandthebutterfly/

   

Tauranga Annual Average Afternoon Temperatures 1914-2018

Weather Eye
with John Maunder

Temperatures have been recorded in the Tauranga area at several sites in the last 100 years, including the current Tauranga Airport site from June 1990.

It's very common for areas such as Tauranga to have had different observation sites during the years, and readings from the earlier sites have been adjusted to the present site using standard climatologically procedures.The temperature series described here is a record of what the temperature would have been if the current observation site, Tauranga Airport, had been used throughout the period.

It's important to note, in considering climate change, the methodology used in computing an official set of climate observations is very important as otherwise erroneous conclusions may be drawn. Traditionally, temperature observations have been recorded with a set of maximum and minimum temperature thermometers.These record the daily maximum temperature, usually recorded in mid-afternoon, and daily minimum temperature, usually recorded just before dawn.

This analysis of temperatures for Tauranga is for average daily maximum temperatures.

The graph below shows details of the average annual daily maximum temperatures (called simply 'afternoon'), for Tauranga for the years 1914-2018.

The long-term average afternoon temperatures for Tauranga for a calendar year is 18.6 degrees Celsius, including the cool years of 18.1 degrees Celsius in 1976, 18.1 degrees Celsius in 1992, 18.2 degrees Celsius in 1923, and 18.3 degrees Celsius in 1918.

In contrast, Tauranga's warmest years (in terms of the average afternoon temperature) are: 20.2 degrees Celsius in 2013, 20.1 degrees Celsius in 1916, 20.0 degrees Celsius in 1998, 19.9 degrees Celsius in 2010 and 2018, and 19.8 degrees Celsius in 1915, 2012, 2016, and 2017. The average afternoon temperature in 2018 was 19.9 degrees Celsius, which made 2017 the fourth equal warmest on record.

Since 1914, there have been fifteen calendar years with an average afternoon temperature of 19.5 degrees Celsius or more. In chronological order these years are: 1914, 1915, 1916, 1928, 1998, 1999, 2005, 2010, 2011, 2013, 2014, 2015, 2016, 2017, and 2018.

In comparison, there have been 11 calendar years with an average afternoon temperature of 18.5 degrees Celsius or less. In chronological order these years are: 1918, 1920, 1923, 1941, 1945, 1965, 1976, 1977, 1980, 1991, and 1992.

The graph of the average afternoon temperatures for the years 1914-2018 shows generally normal variations from year to year from 1915 to the mid-1990's, followed by several years of above-average temperatures, including the last recent seven “warm” years: 2010, 2011, 2013, 2014, 2015, 2016, 2017, and 2018.

The annual average afternoon temperature shows a warming of about 0.8 degrees Celsius during the 51 years from 1963-2013 from 19.0 degrees Celsius, compared with 18.2 degrees Celsius during the 49 years from 1914-1962.

For further information see: https://sites.google.com/site/theweatherclimateeye/




Tauranga December Rainfalls 1898-2018

Weather Eye
with John Maunder

The graph below shows the range of Tauranga's December rainfalls, from an extreme high of 447 mm in 1962 to a low of only 4 mm in 1930.

The second wettest December was 2018, when 278 mm was recorded

The second driest December was in 1994, when only 14 mm fell.

The rainfall for December 2018 was 278 mm.

The long-term average rainfall for Tauranga for December is 100 mm.

The graph of the December rainfall shows, at first glance, normal variations from year to year.

However, there has been an increase in December rainfalls during the last few decades. Indeed, the average December rainfall in Tauranga for the 50-year period from 1961-2010 of 109 mm, is 20 per cent higher than the rainfall for the 50-year period 1911-1960. In contrast, three recent December months (2015, 2016, 2017) have had low rainfalls of 18 mm, 44 mm, and 29 mm.

Since 1898, there have been nine Decembers with a rainfall of 200 mm or more, six of which occurred during the period 1962 to 2018. Seven December months have experienced rainfalls of 30 mm or less. Of significance are the high rainfalls in the consecutive December months of 1962 and 1963, of 447 mm and 224 mm respectively.

In chronological order, the nine-wettest Decembers are 1924 with 225 mm, 1928 with 227 mm, 1936 with 240 mm, 1962 with 447 mm, 1963 with 224 mm, 1996 with 241 mm, 2001 with 208 mm, 2011 with 276 mm, and 2018 with 278 mm.

In contrast, the eighth-driest December months in chronological order are 1902 with 27 mm, 1912 with 22 mm, 1919 with 22 mm, 1930 with 4 mm, 1986 with 30 mm, 1990 with 21 mm, 1994 with 14 mm, and 2015 with 18 mm.

For further information on a range of weather/climate matters see:https://sites.google.com/site/climatediceandthebutterfly/


Tauranga November Average Afternoon Temperatures 1913-2018

Weather Eye
with John Maunder

During November 2013, Tauranga had its warmest November ( average afternoon temperature of 22.3 degrees Celsius), since records began in 1913.

Since then the November temperatures have been 20.5 degrees Celsius in 2014, 20.7 degrees C in 2015, 21.0 degrees C in 2016, 20.0 degrees C in 2017, and 20.4 degrees C in 2018.

Temperatures have been recorded in the Tauranga area at several sites in the last 100 years, including the current Tauranga Airport site from June 1990.

The graph shows details of the average daily maximum temperatures (called simply ‘afternoon') for Tauranga for Novembers from 1913-2018.

The long-term average afternoon temperature in November for Tauranga is 20.1 degrees Celsius, ranging from the cool November months of 1976 (18.4 degrees Celsius), and 1941 (18.5 degrees Celsius), to the warm November months of 2013 (22.3 degrees Celsius), and 1954 (22.0 degrees Celsius).

The graph of the average afternoon temperatures for November shows generally normal variations from November to November during the last 100 years, but of note are the four warm Novembers in the years 2009, 2010, 2011, and 2013.

The average November afternoon temperature during the 50 years from 1963 to 2011 of 20.1 degrees Celsius, is nearly the same as the 20.0 degrees Celsius recorded in the 50 years 1914 to 1961.

From 1913 to 2018, there have been 16 November months with an average afternoon temperature of 21.0 degrees Celsius or more, and seven November months with an average afternoon temperature of less than 19.0 degrees Celsius.

The seventh warmest November months (in terms of afternoon temperatures), on record, in chronological order, are 1945, 1954, 1961, 1982, 2010, 2011, and 2013.

By contrast, the seventh coolest November months (in terms of afternoon temperatures), on record, in chronological order, are 1918, 1930, 1946, 1968, 1976, 1991, and 1985.

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The physicist Leo Szilard once announced to his friend Hans Bethe that he was thinking of keeping a diary: 'I don't intend to publish, I am merely going to record the facts for the information of God.' 'Don't you think God knows the facts?' Bethe asked. 'Yes' said Szilard. ‘He knows the facts, but he does not know THIS version of the facts'

"(From Hans Christian von Baeyer, "Taming the Atom" (from the preface paragraph in "A Short History of Nearly Everything", by Bill Bryson, A Black Swan Book, 2004)

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WEATHEREYE #294

Tauranga November Rainfalls 1898-2018

Weather Eye
with John Maunder

The graph shows the range of November rainfalls from 1898 to 2018 in Tauranga, from an extreme high of 285 mm in 1916 to a low of only 12 mm in 2009.

The second wettest November was 1967, when 240 mm was recorded; the second driest November was in 2011, when only 13 mm fell.

The long-term average rainfall for Tauranga in the month of November is 85 mm. The rainfall for November 2018 was 113 mm..

The graph of the November rainfall shows at first glance normal variations from year to year.

However, there has been a notable decrease in the November rainfalls during the last few years.

Indeed, the average November rainfall in Tauranga for the 50-year period from 1961-2010 of 78 mm is only 85 per cent of the rainfall for the 50-year period 1910-1960.

Since 1898, there have been 11 November months with a rainfall of 150 mm or more (seven of which occurred during the period 1913-1952).

In chronological order, the wettest Novembers are: 1913 with 205 mm, 1916 with 285 mm, 1925 with 167 mm, 1933 with 152 mm, 1936 with 153 mm, 1938 with 174 mm, 1952 with 232 mm, 1967 with 240 mm, 1981 with 191 mm, 1995 with 204 mm, and 1999 with 160 mm.

In terms of dry Novembers, there have been 13 months with rainfall of 30 mm of less, four of which have occurred since 1997.

In chronological order the driest Novembers are 1901 14 mm, 1902 26 mm, 1914 with 17 mm, 1919 with 23 mm, 1928 with 28 mm, 1945 with 20 mm, 1963 with 30 mm, 1982 with 24 mm, 1984 with 19 mm, 1997 with 24 mm, 2009 with 12 mm, 2011 with 13 mm, and 2012 with 27 mm.

*****************************************

The physicist Leo Szilard once announced to his friend Hans Bethe that he was thinking of keeping a diary: 'I don't intend to publish, I am merely going to record the facts for the information of God.' 'Don't you think God knows the facts?' Bethe asked. 'Yes' said Szilard. ‘He knows the facts, but he does not know THIS version of the facts'

"(From Hans Christian von Baeyer, "Taming the Atom" (from the preface paragraph in "A Short History of Nearly Everything", by Bill Bryson, A Black Swan Book, 2004)

**********************************

For further information see: https://sites.google.com/site/climatediceandthebutterfly/





WEATHEREYE # 293

In the Bleak Mid-winter

Weather Eye
with John Maunder

In the bleak mid-winter,

Frosty wind made moan,

Earth stood hard as iron,

Water like a stone,

Snow had fallen,

Snow on snow,

Snow on snow,

In the bleak mid-winter,

Long ago.


These words, from the first verse of the well-known carol, were written by the English poet Christina Rossetti in 1872 in response to a request from the magazine ‘Scribner's Monthly' for a Christmas poem.

It was published posthumously in Rossetti's ‘Poetic Works' in 1904. The poem became a Christmas carol after it appeared in ‘The English Hymnal' in 1906. The text of this Christmas poem has been set to music many times; the most famous settings being composed by Gustav Holst and Harold Edwin Darke in the early 20th Century.

The version by Darke is favoured by cathedral choirs, and is the one usually heard performed on the radio broadcasts of ‘Nine Lessons and Carols' by the King's College choir.

The carol featured in the Queen's Christmas TV message a few year ago

Of some significance is that five years ago on December 15, 2013 the ‘Mail Online' (UK) had the following headlines relating to a severe snow storm, which hit the Holy City – and at the same time Cairo experienced its first snowfall in more than 100 years. Perhaps a reminder that Christmas carols do come alive?

A Christmas card come to Life: Jerusalem hit by worst snowstorm for 20 years, as eight inches fall across Holy City.

- Unusually heavy snowfall, as temperatures dip below freezing.
- Dome of the Rock and Western Wall bathed in white blanket.
- Prime Minister Natanyahu gets in on the fun with family snowball fight.

As all my readers will be aware, the weather is always with us; and although we may all hope that the weather this Christmas and in 2019 will be to our liking, it is perhaps important to remember that in the Southern Hemisphere where the carol ‘In the Bleak Mid-Winter' may seem unusual, there have been two significant and tragic events at Christmas.

The first was on Christmas Eve in New Zealand, in 1953, when the Tangiwai rail disaster occurred with loss of 151 lives following a rapid rise in the Tangiwai river. The second was in Darwin, in Australia on Christmas Day 1974, when Tropical Cyclone Tracy killed 71 people and destroyed 80 per cent of the city's houses.

I take this opportunity of wishing all my readers a very happy Christmas and I will be back in 2019 with some more WeatherEyes.



WEATHEREYE # 292

Climate change and Villach : Is there a connection?

Weather Eye
with John Maunder

Among the many climate science meetings I have attended, the most significant, at least in term of climate change is concerned, is my involvement in the UN sponsored International Conference held in the beautiful town Villach, in Austria in October 1985.

One hundred experts from 30 countries attended the meeting (in contrast to ten to twenty thousand who now attend such meetings), and I was privileged to be the only New Zealander invited. We were all there as experts - and not representing our respective organisations - in various fields of science, endeavouring to do the best we could in looking at the complexities of climate science.

Among the principal findings of this conference was that "while other factors, such as aerosol concentration, changes in solar energy input, and changes in vegetation, may also influence climate, the greenhouse gases are likely to be the most important cause of climate change over the next century”.

At that time, even though I was partly responsible for the writing of the above paragraph, I along with a few of my colleagues, had some misgivings about this phrase, and were somewhat surprised that within a year ‘human-induced global warming' caught the imagination of much of the world. Indeed today, not a day goes by without some mention of ‘global warming', climate change, emission trading schemes, etc, all terms which up until 1980 were the preserve of academic text books.

Despite this concern, a colleague of mine from Australia, Bill Kininmonth, who in 2004 wrote a book called "Climate Change - A Natural Hazard" has mentioned to me on several occasions that I have changed from being the ‘gamekeeper' and become the ‘poacher'. Whether that is true is a matter of opinion. However, irrespective of my personal views on the matter, it is clear that there are two main views held by climate scientists and others on the subject of global warming and climate change.

First, those who are mainly involved in the Intergovernmental Panel on Climate Change and many or most government scientists, plus others, such as Al Gore, and many politicians and most journalists who consider that man, including domestic animals, is the prime cause of recent changes in the climate;

Second, those - in the main some university scientists, many retired climatologists, and a minority of politicians and journalists, who consider that nature is the main cause of changes in the climate.

Twenty years ago, it was unconceivable that the New Zealand Government would have a Minister of Climate Change; indeed back then, as weather forecasters and climatologists we just got on with our job of making the best possible weather forecast and providing the best climate advice to all those who requested information, without guidance or interference from the Government of the day. How things have changed!

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The physicist Leo Szilard once announced to his friend Hans Bethe that he was thinking of keeping a diary: 'I don't intend to publish, I am merely going to record the facts for the information of God.' 'Don't you think God knows the facts?' Bethe asked. 'Yes' said Szilard. ‘He knows the facts, but he does not know THIS version of the facts'

"(From Hans Christian von Baeyer, "Taming the Atom" (from the preface paragraph in "A Short History of Nearly Everything", by Bill Bryson, A Black Swan Book, 2004)

For further information see: https://sites.google.com/site/climatediceandthebutterfly/





WEATHEREYE # 291

The Southern Oscillation Index

Weather Eye
with John Maunder

The Southern Oscillation Index (SOI) is a standardized index based on the observed sea level pressure differences between Tahiti and Darwin, Australia.

The SOI is a leading measure of the large-scale fluctuations in air pressure occurring between the western and eastern tropical Pacific (i.e., the state of the Southern Oscillation) during El Niño and La Niña episodes.

In general, smoothed time series of the SOI correspond very well with changes in ocean temperatures across the eastern tropical Pacific. The negative phase of the SOI represents below-normal air pressure at Tahiti and above-normal air pressure at Darwin. The positive phase of the SOI represents above-normal air pressure at Tahiti and below-normal air pressure at Darwin.

Prolonged periods of negative SOI values coincide with abnormally warm ocean waters across the eastern tropical Pacific typical of El Niño episodes. In contrast, prolonged periods of positive SOI values coincide with abnormally cold ocean waters across the eastern tropical Pacific typical of La Niña episodes. Sustained negative values of the SOI below −8 often indicate El Niño episodes.These negative values are usually accompanied by sustained warming of the central and eastern tropical Pacific Ocean, a decrease in the strength of the Pacific Trade Winds.

Sustained positive values of the SOI above +8 are typical of a La Niña episode.They are associated with stronger Pacific trade winds and warmer sea temperatures to the north of Australia. Waters in the central and eastern tropical Pacific Ocean become cooler during this time.

The graph below ( from the Australian Bureau of Meteorology, BOM) shows monthly values of the SOI from 1880 to November 2018.

The BOM says that surface temperatures in the tropical Pacific Ocean have warmed to El Niño levels over the past fortnight. However, atmospheric indicators of El Niño are largely near normal, suggesting that the ocean and atmosphere are not yet reinforcing each other, or 'coupled'. This reinforcement is critical in any El Niño developing and becoming self-sustaining.

International climate models suggest further warming of the tropical Pacific Ocean is likely, increasing the possibility of coupling occurring in the coming months. Seven out of eight climate models suggests sea surface temperatures will remain above El Niño thresholds until at least March 2019.

The El Niño–Southern Oscillation (ENSO) is currently neutral. While the tropical Pacific Ocean has cooled in the past month, most international climate models forecast warming to resume in the coming weeks, with El Niño development possible in the Southern Hemisphere spring. Therefore, the Bureau's ENSO Outlook remains at El Niño WATCH. El Niño WATCH means there is approximately a 50% chance of El Niño forming in 2018; double the normal chance.

El Nino and La Nina weather affects over New Zealand (source Niwa)

During El Niño, New Zealand tends to experience stronger or more frequent winds from the west in summer, typically leading to drought in east coast areas and more rain in the west.

In winter, the winds tend to be more from the south, bringing colder conditions to both the land and the surrounding ocean.

In spring and autumn south–westerly winds are more common.

La Niña events have different impacts on New Zealand's climate. More north–easterly winds are characteristic, which tend to bring moist, rainy conditions to the north–east of the North Island, and reduced rainfall to the south and south–west of the South Island.

Therefore, some areas, such as central Otago and South Canterbury, can experience drought in both El Niño and La Niña.

Warmer than normal temperatures typically occur over much of the country during La Niña, although there are regional and seasonal exceptions.

Although ENSO events have an important influence on New Zealand's climate, it accounts for less than 25 per cent of the year to year variance in seasonal rainfall and temperature at most New Zealand measurement sites.

***********************

The physicist Leo Szilard once announced to his friend Hans Bethe that he was thinking of keeping a diary: 'I don't intend to publish, I am merely going to record the facts for the information of God.' 'Don't you think God knows the facts?' Bethe asked. 'Yes' said Szilard. ‘He knows the facts, but he does not know THIS version of the facts'

"(From Hans Christian von Baeyer, "Taming the Atom" (from the preface paragraph in "A Short History of Nearly Everything", by Bill Bryson, A Black Swan Book, 2004)

For further information see: https://sites.google.com/site/climatediceandthebutterfly/





WEATHEREYE # 290

Sunspots and the Sun

Weather Eye
with John Maunder

A sunspot is a relatively dark, sharply defined region on the solar disc - marked by an umbra (dark area) which is 2000 degrees Celsius cooler than the effective photosphere temperature. The average diameter of a sunspot is 4000 km, but can exceed 200,000 km.

The NASA Solar Physics website (and other web sites such as the Royal Observatory of Belgium) includes information on sunspot numbers, the ‘Maunder Minimum', and sunspot cycle predictions. The sunspot index is updated monthly and available from 1749. The last time the monthly sunspot number was above 100 for any significant period of time was September 2002 when the value was 109.6, and the last time the value was above 200 was in August 1990 when the value was 200.3.

The peak of latest solar cycle Number 24 was reached in April 2014, with a maximum of the 13-month smoothed sunspot number at 81.8. Since then, solar activity has steadily declined. The monthly mean sunspot number is now less than ten.

As this late maximum comes more than 5 years after the preceding minimum in December 2008, cycle 24 has now entered its long declining phase, as none of the past observed cycles had longer delays between minimum and maximum. Therefore, the average solar activity should progressively decrease towards a minimum around 2019.

We are currently over seven years into solar cycle 24. This the smallest sunspot cycle since solar cycle 14 which had a maximum of 64.2 in February of 1906.

Spotless Days

Since mid-2016, the Sun has occasionally been devoid of sunspots. These spotless disks will gradually become a familiar feature as the solar cycle is heading for its next minimum, currently expected by the end of this decade. The number of spotless days can vary significantly from one solar cycle transit to another. For example, during the previous minimum (around 2008), no less than 817 spotless days were recorded, whereas the minimum period leading into solar cycle 23 (around 1996) counted only 309 such blemishless days.

As the current solar cycle 24 will gradually give way to the new solar cycle 25, several consecutive days and even weeks without sunspots will become the norm. In order to have an idea on the number of spotless days, and how these numbers compare to past solar cycles, the SILSO web site has created a “Spotless Days page”. This page contains graphs and tables on the accumulated number of spotless days, stretches of spotless days, and comparisons to other solar cycles – all supplemented with a word of explanation.

The previous minimum surprised scientists and solar observers by being the deepest in nearly 90 years. Will the upcoming solar cycle minimum show as many spotless days, or will solar cycle 25 take off much faster than expected? The “Spotless Days page” will provide you with a front-row seat on the current status of the solar cycle minimum and the number of spotless days. Enjoy! Perhaps a new “Maunder Minimum” era is upon is!

**********************************

The physicist Leo Szilard once announced to his friend Hans Bethe that he was thinking of keeping a diary: 'I don't intend to publish, I am merely going to record the facts for the information of God.' 'Don't you think God knows the facts?' Bethe asked. 'Yes' said Szilard. ‘He knows the facts, but he does not know THIS version of the facts'

"(From Hans Christian von Baeyer, "Taming the Atom" (from the preface paragraph in "A Short History of Nearly Everything", by Bill Bryson, A Black Swan Book, 2004)

For further information see: https://sites.google.com/site/climatediceandthebutterfly/






WEATHEREYE # 289

Tropospheric Temperatures 1979 to October 2018

Weather Eye
with John Maunder

The chart below shows that since 1979, when reliable satellite observations became available, there has been little overall trend in the average tropospheric temperatures, apart from milder/warmer temperatures since about 1997, and two significant warm periods associated with the El Nino events in 1998 and 2015-16.

The latest global average temperatures of the troposphere updated to October 2018 - observed from US National Oceanic and Atmospheric Administration satellites – are computed by the University of Alabama at Huntsville in the United States. The data shows variations from the 30 year period 1981-2010.

Since 1979, NOAA satellites have been carrying instruments which measure the natural microwave thermal emissions from oxygen in the atmosphere. The intensity of the signals these microwave radiometers measure at different microwave frequencies is directly proportional to the temperature of different, deep layers of the atmosphere.

Every month, researchers at the University of Alabama (Dr John Christy and Dr Roy Spencer) update global temperature datasets that represent the piecing together of the temperature data from a total of fourteen instruments flying on different satellites over the years.

The graph above represents the latest update; updates are usually made within the first week of every month.

Contrary to some reports, the satellite measurements are not calibrated in any way with the global surface-based thermometer records of temperature.

They instead use their own on-board precision redundant platinum resistance thermometers calibrated to a laboratory reference standard before launch.

The troposphere is the lowest layer of Earth's atmosphere.

It contains approximately 75 per cent of the atmosphere's mass and 99 per cent of its water vapour and aerosols.

The average depth of the troposphere is approximately 17 km in the middle latitudes.

The latest data for October 2018 is +0.22 degrees C.

The coolest months since 1979 were September 1984, with minus 0.49 degrees Celsius, and November 1984, with minus 0.42 degrees Celsius.

The warmest months were February 2016 with plus 0.83 degrees C, February and April 1998, both plus 0.76 degrees Celsius, and March 2016 plus 0.73 degrees, and April 2016 plus 0.73 degrees Celsius.

The chart shows the El Nino warming in the 1998 period, and 2015-16, and the Mount Pinatubo, volcanic cooling during 1992-1993.

****************************

The physicist Leo Szilard once announced to his friend Hans Bethe that he was thinking of keeping a diary: 'I don't intend to publish, I am merely going to record the facts for the information of God.' 'Don't you think God knows the facts?' Bethe asked. 'Yes' said Szilard. ‘He knows the facts, but he does not know THIS version of the facts'

"(From Hans Christian von Baeyer, "Taming the Atom" (from the preface paragraph in "A Short History of Nearly Everything", by Bill Bryson, A Black Swan Book, 2004)

For further information see: https://sites.google.com/site/climatediceandthebutterfly



Tauranga October Average Afternoon Temperatures 1913-2018

Weather Eye
with John Maunder

Temperatures have been recorded in the Tauranga area at several sites in the last 100 years, including the current Tauranga Airport site from June 1990.

The graph shows details of the average daily maximum temperatures (called simply ‘afternoon') for Tauranga for October from 1913-2018.

The average afternoon temperature for October 2018 for Tauranga was 19.3 degrees C, which was the equal sixth warmest on record.

The long-term average afternoon temperature in October for Tauranga is 18.1 degrees Celsius, ranging from the cool October months of 1964 (15.7 degrees Celsius), and 1992 (16.5 degrees Celsius), to the warm October months of 2013 (20.3 degrees Celsius), and 1915 (19.9 degrees Celsius).

The graph of the average afternoon temperatures for October shows generally normal variations from October to October during the last 100 years.

The average October afternoon temperatures during the 50 years from 1963-2011 of 18.0 degrees Celsius is slightly cooler than the 18.3 degrees Celsius recorded in the 50 years from 1914-1961.

From 1913 to 2018, there have been fifteen October months with an average afternoon temperature of 19.0 degrees Celsius or more; and eight October months have had an average afternoon temperature of 17.0 degrees Celsius or less.

The five warmest October months (in terms of afternoon temperatures), on record, in chronological order, are 1913, 1915, 1940, 2013, and 2015.

By contrast, the fifth coolest October months (in terms of afternoon temperatures), on record, in chronological order, are 1941, 1964, 1978, 1982, and 1992.

******************************

The physicist Leo Szilard once announced to his friend Hans Bethe that he was thinking of keeping a diary: 'I don't intend to publish, I am merely going to record the facts for the information of God.' 'Don't you think God knows the facts?' Bethe asked. 'Yes' said Szilard. ‘He knows the facts, but he does not know THIS version of the facts'

"(From Hans Christian von Baeyer, "Taming the Atom" (from the preface paragraph in "A Short History of Nearly Everything", by Bill Bryson, A Black Swan Book, 2004)

For further information see: https://sites.google.com/site/climatediceandthebutterfly/



Tauranga October Rainfalls 1898-2018

Weather Eye
with John Maunder

The graph below shows the range of Tauranga's October rainfalls, from an extreme high of 357 mm in 1916 to a low of only 7 mm in 1984.

The second wettest October was 1928, when 269 mm was recorded; and the second driest October was in 1928, when only 11 mm fell.

The long-term average rainfall for Tauranga in the month of October is 110 mm.

The rainfall in October 2018 was 79 mm.

The graph of the October rainfall shows generally normal variations from year to year.

Since 1898, there have been 11 October months with a rainfall of 200 mm or more (10 of which occurred during the period 1900-1958), and only one October month since then has recorded this much. Ten October months have also experienced rainfalls of 25 mm or less.

In chronological order the eleven wettest October months are 1900, 1905, 1916, 1918, 1921, 1926, 1928, 1941, 1952, 1958, and 1983. In contrast the eleventh driest October months are 1906, 1938, 1963, 1965, 1969, 1973, 1984, 1993, 2010, 2013, and 2015.

For further information see:https://sites.google.com/site/theweatherclimateeye/




Arctic and Antarctic Temperatures ..... January 2000 to August 2018

Weather Eye
with John Maunder

Each month Professor Ole Humlum of the The University Centre in Svalbard (UNIS), in Norway publishes on the web his very comprehensive web site updating a large number of charts and related analyses of data from international sources such as NASA.. His latest page can be found at:

 

https://www.climate4you.com/Text/Climate4you

 

One example of what is contained in his web base is a chart of Arctic and Antarctic surface air temperatures from January 2000 to August 2018.

Note.HadCRUT4 is a global temperature dataset, providing gridded temperature anomalies across the world as well as averages for the hemispheres and the globe as a whole. CRUTEM4 and HadSST3 are the land and ocean components of this overall dataset, respectively. These datasets have been developed by the Climatic Research Unit (University of East Anglia) in conjunction with the Hadley Centre (UK Met Office), apart from the sea surface temperature (SST) dataset which was developed solely by the Hadley Centre.

Diagram showing area weighted Arctic (70-90 degrees N) monthly surface air temperature anomalies (HadCRUT4) since January 2000, in relation to the WMO normal period 1961-1990. The thin line shows the monthly temperature anomaly, while the thicker line shows the running 37-month (c. 3 year) average.

Diagram showing area weighted Antarctic (70-90 N) monthly surface air temperature anomalies (HadCRUT4) since January 2000, in relation to the WMO normal period 1961-1990. The thin line shows the monthly temperature anomaly, while the thicker line shows the running 37-month (c. 3 year) average.

https://sites.google.com/site/climatediceandthebutterfly/

Global Temperatures 1996 – August 2018

Weather Eye
with John Maunder

Global temperatures are compiled for various areas including global (land-ocean), global (meteorological stations), three latitude bands, and hemispheric, by the Goddard Institute for Space Studies of NASA.

The graph shows the monthly mean global surface temperature anomaly from the base period 1951-1980, for the period 1996- August 2018. The black line shows meteorological stations only; the dotted line is the land-ocean temperature index obtained from satellite measurements.

For details see data.giss.nasa. (See graphs at the top right hand corner of the front web page and go to months)

The GISS Surface Temperature Analysis (GISTEMP) is an estimate of global surface temperature change. Graphs and tables are updated around the middle of every month using current data files from NOAA GHCN v3 (meteorological stations), ERSST v4 (ocean areas), and SCAR (Antarctic stations), combined as described in our December 2010 publication (Hansen et al. 2010). These updated files incorporate reports for the previous month and also late reports and corrections for earlier month.

The basic GISS temperature analysis scheme was defined in the late 1970's by James Hansen when a method of estimating global temperature change was needed for comparison with one-dimensional global climate models. The scheme was based on the finding that the correlation of temperature change was reasonably strong for stations separated by up to 1200 km, especially at middle and high latitudes. This fact proved sufficient to obtain useful estimates for global mean temperature changes.

The chart above shows that from 1997 to August 2018 there has been a small warming in the global monthly temperatures, and a relatively warm period associated with the recent 2015-2017 El Nino events.


For further information on a wide range of climate matters see:https://sites.google.com/site/climatediceandthebutterfly/




Sea Level Changes

Weather Eye
with John Maunder

Global (or eustatic) sea-level change is measured relative to an idealised reference level, the geoid, which is a mathematical model of planet Earth’s surface. Global sea-level is a function of the volume of the ocean basins and the volume of water they contain. Changes in global sea-level are caused by – but not limited to - four main mechanisms:

Source: www.climat4you.com

1. Changes in local and regional air pressure and wind, and tidal changes introduced by the Moon.

2. Changes in ocean basin volume by tectonic (geological) forces.

3. Changes in ocean water density caused by variations in currents, water temperature and salinity.

4. Changes in the volume of water caused by changes in the mass balance of terrestrial glaciers.

In addition to these there are other mechanisms influencing sea-level; such as storage of ground water, storage in lakes and rivers, evaporation, etc.

Mechanism 1 is controlling sea-level at many sites on a time scale from months to several years. As an example, many coastal stations show a pronounced annual variation reflecting seasonal changes in air pressures and wind speed. Longer-term climatic changes playing out over decades or centuries will also affect measurements of sea-level changes.

Mechanism 2 – with the important exception of earthquakes and tsunamis - typically operates over long (geological) time scales, and is not significant on human time scales. It may relate to variations in the sea-floor spreading rate, causing volume changes in mid-ocean mountain ridges, and to the slowly changing configuration of land and oceans.

Mechanism 3 (temperature-driven expansion) only affects the uppermost part of the oceans on human time scales. Usually, temperature-driven changes in density are more important than salinity-driven changes. Seawater is characterised by a relatively small coefficient of expansion, but the effect should however not be overlooked, especially when interpreting satellite altimetry data. Temperature-driven expansion of a column of seawater will not affect the total mass of water within the column considered and will therefore not affect the potential at the top of the water column. Temperature-driven ocean water expansion will therefore not in itself lead to lateral displacement of water, but only lift the ocean surface locally.

Mechanism 4 (changes in glacier mass balance) is an important driver for global sea-level changes along coasts, for human time scales. Volume changes of floating glaciers – ice shelves – has no influence on the global sea-level, just like volume changes of floating sea ice has no influence. Only the mass-balance of grounded or land-based glaciers is important for the global sea-level along coasts.

Summing up: Mechanism 1 and 4 are the most important for understanding sea-level changes along coasts.

For further information on a range of weather/climate matters see: https://sites.google.com/site/climatediceandthebutterfly/


Tauranga September Average Afternoon Temperatures 1913-2018

Weather Eye
with John Maunder

Temperatures have been recorded in the Tauranga area at several sites in the last 100 years, including the current Tauranga Airport site from June 1990.

The graph shows details of the average daily maximum temperatures (simply called “afternoon”) for Tauranga for September from 1913-2018.

The long-term average afternoon temperature in September for Tauranga is 16.6 degrees C, ranging from the “cool” September months of 1964 (14.8 degrees C), and 1977 (14.9 degrees C), to the “warm” September months of 1915 (18.4 degrees C), and 18.3 degrees in 1914.

The afternoon temperature for 2018 was 17.2 degrees C.

The graph of the average afternoon temperatures for September shows generally "normal" variations from September to September during the last 100 years, but five of the warmest six September months occurred from 1913 to 1921.

From 1913 to 2017, there have been ten September months with an average afternoon temperature of 17.5 degrees C or more, and eight September months with an average afternoon temperature of less than 15.4 degrees C.

The tenth “warmest” September months (in terms of afternoon temperatures) on record, in chronological order, are 1913, 1914, 1915, 1916, 1921, 1926, 1940, 2006, 2009 and 2014.

By contrast, the eighth “coolest” September months (in terms of afternoon temperatures) on record, in chronological order, are 1935, 1964, 1967, 1977, 1992, 1993, 1994 and 1997.

The average afternoon temperature during September for the period 1914-62 was 16.6 degrees, compared with 16.5 degrees from 1963-2011.

For further information see: https://sites.google.com/site/climatediceandthebutterfly/




Tauranga September Rainfalls 1898-2018

Weather Eye
with John Maunder

Rainfalls for the month of September have been recorded in Tauranga since 1898, except for 1904, 1907, 1908, and 1909.

The graph below shows the range of rainfalls from an extreme high of 274 mm in 1973 to a low of only 16 mm in 1965.

The second wettest September was in 1900, when 256 mm was recorded, and the second driest September was in 1944, when only 27 mm fell. The long-term average rainfall for Tauranga for September is 105 mm.

The graph of the September rainfall shows normal variations from year to year. Since 1898, there have been five Septembers with a rainfall of 200 mm or more (four of which occurred during the period 1900 to 1928, but there's only been one since then), compared with seven September months with a rainfalls of 40 mm or less.

The rainfall for September 2018 was 34 mm.

In chronological order, the ten wettest September months (rainfalls over 180 mm) are 1900,1912,1919,1923,1928,1946,1960,1969,1971,1973, and 2017.

In contrast the twelfth driest September months (rainfalls of 50 mm or less) are 1910, 1913, 1914, 1921, 1922, 1944, 1965, 1993, 1987, 2006, 2011 and 2018.

The average rainfall for Tauranga for September for the 50 years 1961-2010 of 103 mm is similar to the rainfall for the previous 50 years (1910-1960).

For further information on a range of weather/climate matters see https://sites.google.com/site/climatediceandthebutterfly/



Sunspots and the Sun

Weather Eye
with John Maunder

A sunspot is a relatively dark, sharply defined region on the solar disc - marked by an umbra (dark area) which is 2000 degrees Celsius cooler than the effective photosphere temperature. The average diameter of a sunspot is 4000 km, but can exceed 200,000 km.

The NASA Solar Physics website (and other web sites such as the Royal Observatory of Belgium) includes information on sunspot numbers, the ‘Maunder Minimum', and sunspot cycle predictions. The sunspot index is updated monthly and available from 1749. The last time the monthly sunspot number was above 100 for any significant period of time was September 2002 when the value was 109.6, and the last time the value was above 200 was in August 1990 when the value was 200.3.

The peak of latest solar cycle Number 24 was reached in April 2014, with a maximum of the 13-month smoothed sunspot number at 81.8. Since then, solar activity has steadily declined. The monthly mean sunspot number is now around 10.

As this late maximum comes more than 5 years after the preceding minimum in December 2008, cycle 24 has now entered its long declining phase, as none of the past observed cycles had longer delays between minimum and maximum. Therefore, the average solar activity should progressively decrease towards a minimum around 2020. However, over the next 2 or 3 years, we can still expect strong but brief peaks of activity caused by the appearance of a few big complex groups, a typical feature of the late phase of solar cycles.

We are currently over seven years into solar cycle 24. This is the smallest sunspot cycle since solar cycle 14 which had a maximum of 64.2 in February of 1906.

Spotless Days

Since mid-2016, the Sun has occasionally been devoid of sunspots. These spotless disks will gradually become a familiar feature as the solar cycle is heading for its next minimum, currently expected by the end of this decade. The number of spotless days can vary significantly from one solar cycle transit to another. For example, during the previous minimum (around 2008), no less than 817 spotless days were recorded, whereas the minimum period leading into solar cycle 23 (around 1996) counted only 309 such blemishless days.

As the current solar cycle 24 will gradually give way to the new solar cycle 25, several consecutive days and even weeks without sunspots will become the norm. In order to have an idea on the number of spotless days, and how these numbers compare to past solar cycles, the SILSO web site has created a “Spotless Days page”. This page contains graphs and tables on the accumulated number of spotless days, stretches of spotless days, and comparisons to other solar cycles – all supplemented with a word of explanation.

The previous minimum surprised scientists and solar observers by being the deepest in nearly 90 years. Will the upcoming solar cycle minimum show as many spotless days, or will solar cycle 25 take off much faster than expected? The “Spotless Days page” will provide you with a front-row seat on the current status of the solar cycle minimum and the number of spotless days. Enjoy! Perhaps a new “Maunder Minimum” era is upon us!



Tropospheric Temperatures 1979 to August 2018

Weather Eye
with John Maunder

The chart below shows that since 1979, when reliable satellite observations became available, there has been little overall trend in the average tropospheric temperatures, apart from milder/warmer temperatures since about 1997, and two significant warm periods associated with the El Nino events in 1998 and 2015-16.

The latest global average temperatures of the troposphere updated to January 2018 - observed from US National Oceanic and Atmospheric Administration satellites – are computed by the University of Alabama at Huntsville in the United States. The data shows variations from the 30 year period 1981-2010.

Since 1979, NOAA satellites have been carrying instruments which measure the natural microwave thermal emissions from oxygen in the atmosphere. The intensity of the signals these microwave radiometers measure at different microwave frequencies is directly proportional to the temperature of different, deep layers of the atmosphere. Every month, researchers at the University of Alabama (Dr John Christy and Dr Roy Spencer) update global temperature datasets that represent the piecing together of the temperature data from a total of fourteen instruments flying on different satellites over the years.

The graph above represents the latest update; updates are usually made within the first week of every month. Contrary to some reports, the satellite measurements are not calibrated in any way with the global surface-based thermometer records of temperature. They instead use their own on-board precision redundant platinum resistance thermometers calibrated to a laboratory reference standard before launch.

The troposphere is the lowest layer of Earth's atmosphere.

It contains approximately 75 per cent of the atmosphere's mass and 99 per cent of its water vapour and aerosols.

The average depth of the troposphere is approximately 17 km in the middle latitudes.

The tropospheric temperature data for 2011 is January 0.0 degrees Celsius, February -0.02, March -0.10, April +0.12, May +0.14, June +0.32, July +0.38, August +0.33, September +0.29, October +0.12, November +0.12, December +0.10 degrees.

The data for 2012 is: January -0.09 degrees, February -0.12, March +0.11, April +0.29, May +0.29, June +0.37, July +0.28, August +0.34, November +0.28, December +0.20 degrees.

The data for 2013 is: January +0.50 degrees, February +0.18, March +0.20, April +0.10, May +0.07, June +0.30, July +0.17, August +0,16, September +0.37, October +0.29, November +0.19, December +0.23 degrees.

The data for 2014 is: January +0.30 degrees, February +0.18, March +0.17, April +0.19, May +0.33, June +0.31, July +0.30, August +0.20, September +0.30, October +0.37, November +0.33, and December +0.33 degrees Celsius.

The data for 2015 is: January +0.20 degrees C, February +0.18 degrees C, March +0.14 degrees C, April +0.07 degrees C, May +0.30 degrees C, June +0.32 degrees C, July +0.18 degrees C, August +0.22 degrees C, September +0.20 degrees C, October +0.32 degrees C, November +0.40 degrees C, and December +0.48 degrees C.

The data for 2016 is: January +0.55 degrees C, February +0.83 degrees C, March +0.73 degrees C, April +0.71 degrees C, May +0.55 degrees, June +0.33 degrees C, July +0.39 degrees C, August +0.38 degrees C, September +0.44 degrees C, October +0.35 degrees, November +0.40 degrees C, and December +0.24 degrees C.

The data for 2017 is: January +0.31 degrees C, February +0.35 degrees C, March +0.37 degrees C, April +0.40 degrees C , May +0.47 degrees C , June +0.21 degrees C, July +0.28 degrees C, August +0.41 degrees C, September +0.54 degrees C, October +0.63 degrees C, November +0.50 degrees C, and December +0.30 degrees C.

The data for 2018 is: January +0.26 degrees C. February +0.20, March +0.24, April +0.21, May +0.28, June +0.23, July 0.32 , and August +0.19 degrees C.

The coolest months since 1979 were September 1984, with minus 0.49 degrees Celsius, and November 1984, with minus 0.42 degrees Celsius.

The warmest months were February 2016 with plus 0.83 degrees C, February and April 1998, both plus 0.76 degrees Celsius, and March 2016 plus 0.73 degrees, and April 2016 plus 0.73 degrees Celsius.

The chart shows the El Nino warming in the 1998 period, and 2015-16, and the Mount Pinatubo, volcanic cooling during 1992-1993.

For for information see: https://sites.google.com/site/climatediceandthebutterfly



Tauranga August Average Afternoon Temperatures 1913-2018

Weather Eye
with John Maunder

Temperatures have been recorded in the Tauranga area at several sites in the last 100 years, including the current Tauranga Airport site from June 1990.

The graph shows details of the average daily maximum temperatures, called simply ‘afternoon' for Tauranga for August from 1913-2018. The average for August 2018 was 15.6 degrees Celsius.

The long-term average afternoon temperature in August for Tauranga is 14.8 degrees Celsius. The coolest August months have been 1932 with 13.8 degrees Celsius, and 1941 and 1992 recording 13.9 degrees Celsius.

The warm August months have been 2013 with 16.7 degrees Celsius, and 1915 with 16.4 degrees Celsius, while 2009 had 16.2 degrees Celsius.

The graph of the average afternoon temperatures for August shows generally normal variations from August to August during the last 100 years.

But several recent August months have been a little warmer than others since 1913. This includes August 2013, the warmest on record with a temperature of 16.7 degrees Celsius, which was 1.9 degrees Celsius above average.

From 1913 to 2018, there have been 11 August months with an average afternoon temperature of 15.8 degrees Celsius or more.

Thirteen August months have had an average afternoon temperature of less than 14.3 degrees Celsius.

The sixth warmest August months – in terms of afternoon temperatures – on record in chronological order are: 1915, 1967, 1971, 2009, 2012 and 2013. By contrast, the fifth coolest August months – in terms of afternoon temperatures – on record, in chronological order are: 1932, 1941, 1966, 1992 and 2004.

The average afternoon temperatures during August for the period 1914-1963 were 14.7 degrees Celsius, compared with 15.0 degrees Celsius from 1964 to 2013.

For further information on a range of weather/climate matters see: https://sites.google.com/site/theweatherclimateeye/





Tauranga August Rainfalls 1898-2018

Weather Eye
with John Maunder

Rainfalls for the month of August have been recorded in Tauranga since 1898, except for 1904, 1907, 1908 and 1909.

From January 1898 to December 1904, the observation site was described as the Tauranga Harbour, from November 1904 to April 1907 the site was described as simply ‘Tauranga'. From January 1910 to December 1923 the site was Waikareao, in Otumoetai; from January 1924 to September 1940 the site was at 148 Waihi Rd, in Judea; from October 1940 to January 1941 the site was at Te Puna; and from February 1941 to now, the site is Tauranga Airport.

The methodology use in adjusting the older sites to the current observing site is published in the ‘NZ Meteorological Service Miscellaneous Publication' No 180 in 1984.

It is considered that the homogeneous rainfall series described here is a fair and true record of what the rainfall would have been if the current observation site (Tauranga Airport) had been used since 1898.

This should be coupled with the understanding that although standard accepted methodologies have been used, any adjustments are only estimates of what would have occurred if the location of the rainfall records had always been in the same place with the same surroundings and the same or similar recording gauge.

In terms of climate change (such as is it getting wetter or drier, or warmer or colder), the methodology used in computing an ‘official' set of climate observations is very important, as otherwise erroneous conclusions may be drawn.

The graph shows the range of rainfalls from an extreme high of 274 mm in 2010 to a low of only 17 mm in 1914.

The second wettest August was 1916 when 263 mm was recorded, and the second driest August was in 1982 when only 31 mm fell.

The long-term average rainfall for Tauranga for August is 124 mm. The rainfall for Tauranga for August 2018 was 140 mm.

The graph of the August rainfall shows normal variations from year-to-year.

There is a small decrease in the overall August rainfalls during the last 50 years – from 1961-2010 – from an average of 121 mm, compared with an average of 133 mm during the 50 years from 1911-1960. Since 1898, there have been 11 August months with a rainfall of 220 mm or more – with 10 occurring during 1900 to 1976 – and only one August month since then 2010, which was the highest rainfall for any August. Only five August months have had rainfalls of 50 mm or less.

Chronologically, the 11 wettest August months are 1913, 1916, 1920, 1927, 1938, 1942, 1957, 1965, 1970, 1976 and 2010.

In contrast, chronologically the five driest August months are 1914, 1921, 1982, 1983 and 2002.

For further information see: https://sites.google.com/site/theweatherclimateeye/



The Southern Oscillation Index

Weather Eye
with John Maunder

The Southern Oscillation Index (SOI) is a standardized index based on the observed sea level pressure differences between Tahiti and Darwin, Australia.

The SOI is a leading measure of the large-scale fluctuations in air pressure occurring between the western and eastern tropical Pacific (i.e., the state of the Southern Oscillation) during El Niño and La Niña episodes.

In general, smoothed time series of the SOI correspond very well with changes in ocean temperatures across the eastern tropical Pacific. The negative phase of the SOI represents below-normal air pressure at Tahiti and above-normal air pressure at Darwin. The positive phase of the SOI represents above-normal air pressure at Tahiti and below-normal air pressure at Darwin.

Prolonged periods of negative SOI values coincide with abnormally warm ocean waters across the eastern tropical Pacific typical of El Niño episodes. In contrast, prolonged periods of positive SOI values coincide with abnormally cold ocean waters across the eastern tropical Pacific typical of La Niña episodes. Sustained negative values of the SOI below −8 often indicate El Niño episodes.These negative values are usually accompanied by sustained warming of the central and eastern tropical Pacific Ocean, a decrease in the strength of the Pacific Trade Winds.

Sustained positive values of the SOI above +8 are typical of a La Niña episode.They are associated with stronger Pacific trade winds and warmer sea temperatures to the north of Australia. Waters in the central and eastern tropical Pacific Ocean become cooler during this time.

The graph below ( from the Australian Bureau of Meteorology) shows monthly values of the SOI from 1880 to early August 2018..

The El Niño–Southern Oscillation (ENSO) is currently neutral. While the tropical Pacific Ocean has cooled in the past month, most international climate models forecast warming to resume in the coming weeks, with El Niño development possible in the Southern Hemisphere spring. Therefore, the Bureau's ENSO Outlook remains at El Niño WATCH. El Niño WATCH means there is approximately a 50% chance of El Niño forming in 2018; double the normal chance.

El Nino and La Nina weather affects over New Zealand (source Niwa)

During El Niño, New Zealand tends to experience stronger or more frequent winds from the west in summer, typically leading to drought in east coast areas and more rain in the west. In winter, the winds tend to be more from the south, bringing colder conditions to both the land and the surrounding ocean. In spring and autumn south–westerly winds are more common.

La Niña events have different impacts on New Zealand's climate. More north–easterly winds are characteristic, which tend to bring moist, rainy conditions to the north–east of the North Island, and reduced rainfall to the south and south–west of the South Island.

Therefore, some areas, such as central Otago and South Canterbury, can experience drought in both El Niño and La Niña.

Warmer than normal temperatures typically occur over much of the country during La Niña, although there are regional and seasonal exceptions.

Although ENSO events have an important influence on New Zealand's climate, it accounts for less than 25 per cent of the year to year variance in seasonal rainfall and temperature at most New Zealand measurement sites.

For further information see: https://sites.google.com/site/climatediceandthebutterfly/




Tropospheric Temperatures 1989- July 2018

Weather Eye
with John Maunder

The chart below shows that since 1979, when reliable satellite observations became available, there has been little overall trend in the average tropospheric temperatures, apart from milder/warmer temperatures since about 1997, and two significant warm periods associated with the El Nino events in 1998 and 2015-16

The latest global average temperatures of the troposphere updated to July 2018 - observed from US National Oceanic and Atmospheric Administration satellites – are computed by the University of Alabama at Huntsville in the United States. The data shows variations from the 30 year period 1981-2010.

Since 1979, NOAA satellites have been carrying instruments which measure the natural microwave thermal emissions from oxygen in the atmosphere. The intensity of the signals these microwave radiometers measure at different microwave frequencies is directly proportional to the temperature of different, deep layers of the atmosphere. Every month, researchers at the University of Alabama (Dr John Christy and Dr Roy Spencer) update global temperature datasets that represent the piecing together of the temperature data from a total of fourteen instruments flying on different satellites over the years.

The graph above represents the latest update; updates are usually made within the first week of every month. Contrary to some reports, the satellite measurements are not calibrated in any way with the global surface-based thermometer records of temperature. They instead use their own on-board precision redundant platinum resistance thermometers calibrated to a laboratory reference standard before launch.

The troposphere is the lowest layer of Earth's atmosphere.

It contains approximately 75 per cent of the atmosphere's mass and 99 per cent of its water vapour and aerosols.

The average depth of the troposphere is approximately 17 km in the middle latitudes.

The tropospheric temperature data for 2011 is January 0.0 degrees Celsius, February -0.02, March -0.10, April +0.12, May +0.14, June +0.32, July +0.38, August +0.33, September +0.29, October +0.12, November +0.12, December +0.10 degrees.

The data for 2012 is: January -0.09 degrees, February -0.12, March +0.11, April +0.29, May +0.29, June +0.37, July +0.28, August +0.34, November +0.28, December +0.20 degrees.

The data for 2013 is: January +0.50 degrees, February +0.18, March +0.20, April +0.10, May +0.07, June +0.30, July +0.17, August +0,16, September +0.37, October +0.29, November +0.19, December +0.23 degrees.

The data for 2014 is: January +0.30 degrees, February +0.18, March +0.17, April +0.19, May +0.33, June +0.31, July +0.30, August +0.20, September +0.30, October +0.37, November +0.33, and December +0.33 degrees Celsius.

The data for 2015 is: January +0.20 degrees C, February +0.18 degrees C, March +0.14 degrees C, April +0.07 degrees C, May +0.30 degrees C, June +0.32 degrees C, July +0.18 degrees C, August +0.22 degrees C, September +0.20 degrees C, October +0.32 degrees C, November +0.40 degrees C, and December +0.48 degrees C.

The data for 2016 is: January +0.55 degrees C, February +0.83 degrees C, March +0.73 degrees C, April +0.71 degrees C, May +0.55 degrees, June +0.33 degrees C, July +0.39 degrees C, August +0.38 degrees C, September +0.44 degrees C, October +0.35 degrees, November +0.40 degrees C, and December +0.24 degrees C.

The data for 2017 is: January +0.31 degrees C, February +0.35 degrees C, March +0.37 degrees C, April +0.40 degrees C , May +0.47 degrees C , June +0.21 degrees C, July +0.28 degrees C, August +0.41 degrees C, September +0.54 degrees C, October +0.63 degrees C, November +0.50 degrees C, and December +0.30 degrees C.

The data for 2018 is January +0.26 degrees C, February + 0.20 degrees C, March + 0.24 degrees C, April +0.21 degrees C, May +0.28 degrees C, June +0.23 degrees C, and July +0.32 degrees C.

The coolest months since 1979 were September 1984, with minus 0.49 degrees Celsius, and November 1984, with minus 0.42 degrees Celsius.

The warmest months were February 2016 with plus 0.83 degrees C, February and April 1998, both plus 0.76 degrees Celsius, and March 2016 plus 0.73 degrees, and April 2016 plus 0.73 degrees Celsius.

The chart shows the El Nino warming in the 1998 period, and 2015-16, and the Mount Pinatubo, volcanic cooling during 1992-1993.


Tauranga: Average July Afternoon Temperatures 1913-2018

Weather Eye
with John Maunder

The graph below shows details of the average daily maximum temperatures, called ‘afternoon', for Tauranga for July from 1913-2018. The temperature for July 2018 was 15.1 degrees Celsius.

It's very common for areas such as Tauranga to have had different observation sites during the years, and readings from the earlier sites have been adjusted to the present site using standard climatologically procedures.The temperature series described here is a record of what the temperature would have been if the current observation site, Tauranga Airport, had been used throughout the period.

It's important to note, in considering climate change, the methodology used in computing an official set of climate observations is very important as otherwise erroneous conclusions may be drawn.

Traditionally, temperature observations have been recorded with a set of maximum and minimum temperature thermometers.

These record the daily maximum temperature, usually recorded in mid-afternoon, and daily minimum temperature, usually recorded just before dawn.

This analysis of temperatures for Tauranga is for average daily maximum temperatures.

The long-term average afternoon temperature in July for Tauranga is 14.1 degrees Celsius, ranging from cool July months of 1918 and 1939, both 12.3 degrees Celsius, and 1965, with 12.9 degrees Celsius.

Warm July months included 1916 and 2010, both 15.8 degrees Celsius, and 1915 with 15.7 degrees Celsius.

The graph of the average afternoon temperatures for July shows generally normal variations from July to July in the last 100 years.

But several July months since 1997 have been a little warmer than many of the July months since 1913.

From 1913 to 2018, there have been 6 July months with an average afternoon temperature of 15.2 degrees Celsius or more, and 11 July months with an average afternoon temperature of less than 13.3 degrees Celsius.

The 6 mildest July months for afternoon temperatures on record, in chronological order are: 1915, 1916, 1917, 1984, 1998, and 2000..

By contrast, the seven coolest July months for afternoon temperatures on record, in chronological order are: 1918, 1929, 1935, 1939, 1963, 1965, and 1969.

The average afternoon temperature for Tauranga for July for 49 years from 1914-1962 was 14.0 degrees Celsius, compared with the average afternoon temperature for Tauranga for July for 49 years from 1963-2011 was 14.2 degrees Celsius.

For further information on a range of weather and climate matters see:https://sites.google.com/site/thebutterflyandtheclimatedice/





Tauranga July Rainfalls 1898-2018

Weather Eye
with John Maunder

Rainfalls for the month of July have been recorded in Tauranga since 1898, except for 1904, 1907, 1908, and 1909.

The graph for the period 1898-2018 shows the range of rainfalls from an extreme high of 348 mm in 1951, to a low of only 2 mm in 1902.

The rainfall for July 2018 was 93 mm. The graph shows the second wettest July was 2012 when 328 mm was recorded, and the second driest July was in 1983 when only 22 mm fell.

The long-term average rainfall for Tauranga for July is 129 mm. The graph of the July rainfall shows ‘normal' variations from year to year.

There is a very small decrease in the overall July rainfalls during the last 50 years (1961-2010) from an average of 127 mm, compared with an average of 132 mm during the 50 years from 1911-1960.

Since 1898, there have been 13 July months with a rainfall of 200 mm or more, but only four July months with rainfalls of 40 mm or less.

The ten wettest July months (in chronological order) have been 1905, 1927, 1938, 1951,1963,1979,1988, 2007, 2008, and 2012. The ten driest July months ( in chronological order) have been 1902, 1918, 1922, 1949, 1969, 1975, 1983, 1997, 2001, and 2010,

For further information on a variety of weather and climate matters see https://sites.google.com/site/nzrainfalls/newzealandmonthlyrainfalls




Yearly Temperatures in England 1700-2018

Weather Eye
with John Maunder

Yearly mean temperatures have been recorded in Central England since about 1700. It is the longest temperature series in the world derived from instrumental records. It shows an increase in temperature of approximately 1.3°C degrees from the end of the 17th Century to the end of the 20th Century/beginning of 21st Century. Subtle difference in timing between the warming/cooling phases between the Central England record and the other localities may reflect local climate variation, but the similarity in events between continents suggests the Central England Temperature record is recording global temperature patterns.

Records of sunspot numbers began in 1610 such that detailed estimates of solar variation for the years covered by the England temperature record can be made without resort to the use of proxy data. Reconstructions of total solar radiance (TSR) differ in magnitude, but there is agreement in form with 4 peaks and 4 to 6 troughs occurring over the time-scale of the England temperate record These are: a minimum in TSR associated with the Maunder Sunspot Minimum in the latter half of the 17th Century; a peak, possibly bi-modal approaching modern TSR values during the 18th Century; a well-defined trough corresponding with the Dalton Sunspot Minimum between 1800- 1820; a poorly defined TSR peak in the mid 19th Century; a reduction in TSR during the late 19th Century; increasing TSAR during the early 20th Century; a decrease in TSR from around 1950- 1975; and a second phase of TSR increase in the late 20th Century.

There is good correspondence with TSR throughout the England temperature record, with warm events correlating with high TSR and cool phases correlating with plateaus or decreases in TSR. However, for temperature increases from the beginning of the Industrial Revolution (Maunder Minimum and Dalton Minimum to end of 20th Century), high TSR models can account for only 63-67% of the temperature increase. This would suggest that one third of Global Warming/Climate Change can be attributed to anthropogenic global warming. Approximately two-thirds [0.8°C to 0.9°C] of climate warming since the mid-late 18th Century [1.3°C] can be attributed to solar causes, suggesting warming due to anthropogenic causes over the last two centuries is 0.4 to 0.5°C.

Source Alan D Smith

“An Analysis of Climate Forcing's from the Central

England Temperature Record”

British Journal of Environment & Climate Change

7(2): 113-118, 2017

 
For further information see:  https://sites.google.com/site/theweatherclimateeye/


Tropospheric Temperatures 1989 - June 2018

Weather Eye
with John Maunder

The chart below shows that since 1979, when reliable satellite observations became available, there has been little overall trend in the average tropospheric temperatures, apart from milder/warmer temperatures since about 1997, and two significant warm periods associated with the El Nino events in 1998 and 2015-16

The latest global average temperatures of the troposphere updated to June 2018- observed from US National Oceanic and Atmospheric Administration satellites – are computed by the University of Alabama at Huntsville in the United States. The data shows variations from the 30 year period 1981-2010.

Since 1979, NOAA satellites have been carrying instruments which measure the natural microwave thermal emissions from oxygen in the atmosphere. The intensity of the signals these microwave radiometers measure at different microwave frequencies is directly proportional to the temperature of different, deep layers of the atmosphere. Every month, researchers at the University of Alabama (Dr John Christy and Dr Roy Spencer) update global temperature datasets that represent the piecing together of the temperature data from a total of fourteen instruments flying on different satellites over the years.

The graph above represents the latest update; updates are usually made within the first week of every month. Contrary to some reports, the satellite measurements are not calibrated in any way with the global surface-based thermometer records of temperature. They instead use their own on-board precision redundant platinum resistance thermometers calibrated to a laboratory reference standard before launch.

The troposphere is the lowest layer of Earth's atmosphere.

It contains approximately 75 per cent of the atmosphere's mass and 99 per cent of its water vapour and aerosols.

The average depth of the troposphere is approximately 17 km in the middle latitudes.

The tropospheric temperature data for 2011 is January 0.0 degrees Celsius, February -0.02, March -0.10, April +0.12, May +0.14, June +0.32, July +0.38, August +0.33, September +0.29, October +0.12, November +0.12, December +0.10 degrees.

The data for 2012 is: January -0.09 degrees, February -0.12, March +0.11, April +0.29, May +0.29, June +0.37, July +0.28, August +0.34, November +0.28, December +0.20 degrees.

The data for 2013 is: January +0.50 degrees, February +0.18, March +0.20, April +0.10, May +0.07, June +0.30, July +0.17, August +0,16, September +0.37, October +0.29, November +0.19, December +0.23 degrees.

The data for 2014 is: January +0.30 degrees, February +0.18, March +0.17, April +0.19, May +0.33, June +0.31, July +0.30, August +0.20, September +0.30, October +0.37, November +0.33, and December +0.33 degrees Celsius.

The data for 2015 is: January +0.20 degrees C, February +0.18 degrees C, March +0.14 degrees C, April +0.07 degrees C, May +0.30 degrees C, June +0.32 degrees C, July +0.18 degrees C, August +0.22 degrees C, September +0.20 degrees C, October +0.32 degrees C, November +0.40 degrees C, and December +0.48 degrees C.

The data for 2016 is: January +0.55 degrees C, February +0.83 degrees C, March +0.73 degrees C, April +0.71 degrees C, May +0.55 degrees, June +0.33 degrees C, July +0.39 degrees C, August +0.38 degrees C, September +0.44 degrees C, October +0.35 degrees, November +0.40 degrees C, and December +0.24 degrees C.

  • The data for data for 2017 is: January +0.31 degrees C, February +0.35 degrees C, March +0.37 degrees C, April +0.40 degrees C , May +0.47 degrees C , June +0.21 degrees C, July +0.28 degrees C, August +0.41 degrees C, September +0.54 degrees C, October +0.63 degrees C, November +0.50 degrees C, and December +0.30 degrees C.
  •  
  • The data for 2018 is January +0.26 degrees C, February + 0.20 degrees C, March + 0.24 degrees C, April +0.21 degrees C, May +0.23 degrees C, and June +0.21 degrees C.

The coolest months since 1979 were September 1984, with minus 0.49 degrees Celsius, and November 1984, with minus 0.42 degrees Celsius.

The warmest months were February 2016 with plus 0.83 degrees C, February and April 1998, both plus 0.76 degrees Celsius, and March 2016 plus 0.73 degrees, and April 2016 plus 0.73 degrees Celsius.

The chart shows the El Nino warming in the 1998 period, and 2015-16, and the Mount Pinatubo, volcanic cooling during 1992-1993.

For for information see: https://sites.google.com/site/climatediceandthebutterfly




Sunspots and the Maunder Minimum Revisited

Weather Eye
with John Maunder

A sunspot is a relatively dark, sharply defined region on the solar disc - marked by an umbra (dark area) which is 2000 degrees Celsius cooler than the effective photosphere temperature.

The average diameter of a sunspot is 4000 km, but can exceed 200,000 km.

The NASA Solar Physics website (and other web sites such as the Royal Observatory of Belgium) includes information on sunspot numbers, the ‘Maunder Minimum', and sunspot cycle predictions. The sunspot index is updated monthly and available from 1749. The last time the monthly sunspot number was above 100 for any significant period of time was September 2002 when the value was 109.6, and the last time the value was above 200 was in August 1990 when the value was 200.3.

The peak of latest solar cycle Number 24 was reached in April 2014, with a maximum of the 13-month smoothed sunspot number at 81.8. Since then, solar activity has steadily declined. The monthly mean sunspot number is now around 20, and for the 16 days to July 16, 2018 here have been no sunspots.

As this late maximum comes more than 5 years after the preceding minimum in December 2008, cycle 24 has now entered its long declining phase, as none of the past observed cycles had longer delays between minimum and maximum. Therefore, the average solar activity should progressively decrease towards a minimum around 2020. However, over the next 2 or 3 years, we can still expect strong but brief peaks of activity caused by the appearance of a few big complex groups, a typical feature of the late phase of solar cycles.

We are currently over seven years into solar cycle 24. This the smallest sunspot cycle since solar cycle 14 which had a maximum of 64.2 in February of 1906.

Spotless Days

Since mid-2016, the Sun has occasionally been devoid of sunspots. These spotless disks will gradually become a familiar feature as the solar cycle is heading for its next minimum, currently expected by the end of this decade. The number of spotless days can vary significantly from one solar cycle transit to another. For example, during the previous minimum (around 2008), no less than 817 spotless days were recorded, whereas the minimum period leading into solar cycle 23 (around 1996) counted only 309 such blemishless days.

As the current solar cycle 24 will gradually give way to the new solar cycle 25, several consecutive days and even weeks without sunspots will become the norm. In order to have an idea on the number of spotless days, and how these numbers compare to past solar cycles, the SILSO web site has created a “Spotless Days page”. This page contains graphs and tables on the accumulated number of spotless days, stretches of spotless days, and comparisons to other solar cycles – all supplemented with a word of explanation.

The previous minimum surprised scientists and solar observers by being the deepest in nearly 90 years. Will the upcoming solar cycle minimum show as many spotless days, or will solar cycle 25 take off much faster than expected? The “Spotless Days page” will provide you with a front-row seat on the current status of the solar cycle minimum and the number of spotless days. Enjoy! Perhaps a new “Maunder Minimum” era is upon is!

For further information see: https://sites.google.com/site/johnmaunder/the-maunder-minmium---300-years-on




Tauranga June Average Afternoon Temperatures 1913-2018

Weather Eye
with John Maunder

Temperatures have been recorded in the Tauranga area at several sites during the last 100 years, including at the current Tauranga Airport site from June 1990.

The graph shows details of the average daily maximum temperatures, called simply ‘afternoon', for Tauranga for June from 1913-2018.

The long-term average afternoon temperature in June for Tauranga is 14.7 degrees Celsius.

The cool' June months were in 1972 with 13.0 degrees Celsius, 1936 with 13.2 degrees Celsius, and 1933 with 13.3 degrees Celsius.

The ‘warm' June months include last year , 2014 with 16.9 degrees Celsius, 1916 and 2011, both with 16.6 degrees Celsius, and June 2016 with 16.5 degrees C.

June 2014 had an average afternoon temperature of 16.9 degrees Celsius was the warmest June on record since observations were first made in 1913. The temperature in June 2018 was a relatively cool 15.4 degrees Celsius.

The graph of the average afternoon temperatures for June shows generally ‘normal' variations from June to June during the last 100 years.

But many of the last 15 June months since 1996 have been a little ‘warmer' than other June months since 1913.

From 1913 to 2018, there have been 15 June months with an average afternoon temperature of 15.6 degrees Celsius or more, and 12 June months with an average afternoon temperature of less than 13.9 degrees Celsius.

The ninth ‘warmest' June months on record, in chronological order, are: 1916, 1971, 1981, 1998, 1999, 2002, 2003, 2011, 2014, and 2016.

By contrast, the seventh ‘coolest' June months on record, in chronological order, are 1933, 1936, 1941, 1944,1969, 1972 and 1976.

The average afternoon temperature in June during the period 1914-1962 was 14.7 degrees Celsius compared with 14.8 degrees Celsius from 1963 to 2011.

For further information see https://sites.google.com/site/theweatherclimateeye/






Weather and Philately

Weather Eye
with John Maunder

On July 1, 2016 (Canada Day) Canada Post unveiled five new stamps designed to showcase one of Canadians’ most popular topics: the weather. The five stamps, issued to coincide with the 175th anniversary of continuous weather observing in Canada, feature weather phenomena in all their photographic splendour.

The five photographs come from every corner of Canada. Daryl Benson snapped hoar frost covering a tree near Beaumont, Alberta. Geoff Whiteway focused on hazy, early-morning fog at Cape Spear Lighthouse National Historic Site in Newfoundland and Labrador. In Saint-Gideon, Quebec, Mike Grandmaison chased a rain shower to shoot a double rainbow, while Dave Reede captured radiant flashes of lightning near Winnipeg, Manitoba. Further north, in Iqaluit, Nunavut, Frank Reardon caught rarely witnessed sun dogs, created by ice crystals in the air, and posted the photograph on The Weather Network, where Canada Post discovered it.

“From coast-to-coast-to-coast Canada is known for its diversity, and weather is no exception. The images captured in weather wonders illustrate the natural beauty that can be seen across our country,” says the Honourable Lisa Raitt, Minister of Transport, responsible for Canada Post.

“Canadians love to talk about the weather,” says Canada Post President and CEO Deepak Chopra. “Our stamp programmme celebrates the people, stories and attributes that capture the Canadian experience and we can all reminisce on a special weather moment.”

Many countries (including New Zealand) have also published stamps relating to a weather/climate topic and a a Finish climatologist (Reino Heino) has made an in-depth study of this subject. Some of his research was published in 2008 in assocaiated with the World Meteorological Organization (WMO) and the Universal Postal Union (UPU). The title of his book “From Weather Gods to Modern Meteorology: A Philatelic Journey” is highly recommended. This book of meteorology-related stamps and postal history items, traces the development of weather-related activities, as illustrated in the philatelic pictorial material published by the postal administration of numerous countries.

For further information on a variety of weather topic see: https://sites.google.com/site/theweatherclimateeye/

*******************************

Villach 1985 and Climate Change

Weather Eye
with John Maunder

Among the many climate science meetings I've attended, the most significant – at least in terms of climate change is concerned – was my involvement in the UN-sponsored International Conference in Villach, Austria, in October 1985.

About 100 from 30 countries attended this meeting – in contrast to the 20,000 who now attend such meetings – and I was privileged to be the only New Zealander invited.

We were all there as experts – not representing our respective organisations or necessarily the views of our respective Governments – in various fields of science, endeavouring to do the best we could in looking at the complexities of climate science.

Among principal findings of this conference was: “while other factors, such as aerosol concentration, changes in solar energy input, and changes in vegetation, may also influence climate, greenhouse gases are likely to be the most important cause of climate change over the next century”.

At the time, even though I was partly responsible for the writing of the above paragraph, I along with a few of my colleagues, had some misgivings about this phrase.

And I was somewhat surprised that within a year ‘human-induced global warming' caught the imagination of many around the world.

Today not a day goes by without some mention of global warming, climate change etc – all terms which up until 1980 were the preserve of academic text books, and terms such as ‘emission trading schemes', weren't even thought.

Despite this concern, a colleague of mine from Australia, Bill Kininmonth, who in 2004 wrote an excellent book called ‘Climate Change - A Natural Hazard' has mentioned to me on several occasions that I've changed from being a ‘gamekeeper' and become the ‘poacher'.

Whether this is true is a matter of opinion. However, irrespective of my personal views on the matter, it's clear there are two main views held by climate scientists and others on the subject of global warming and climate change.

First, those mainly involved in the Intergovernmental Panel on Climate Change IPCC) and many or most government scientists, plus others, such as Al Gore, many politicians and most journalists who consider humans and human activity, including domestic animals, is the prime cause of recent changes in the climate.

Second, there are are those – including some university scientists, several retired climatologists and climate scientists, and a minority of politicians and journalists, who consider nature is the main cause of changes in the climate. The Australian SKY TV programmme has each weekday the Andrew Bolt programme which very often has an item on climate which is generally in contact to what we see or read about in NZ.

Thirty or twenty yaers ago it was unconceivable the New Zealand Government and most other governments in the world would have a Minister of Climate Change.

Back then, as weather forecasters and climatologists, we just got on with our job of making the best possible weather forecast and providing the best climate advice to all who requested information – without guidance or interference from the Government of the day.

How things have changed.

For further information on a range of weather/climate matters see: https://sites.google.com/site/theweatherclimateeye/

https://www.sunlive.co.nz/blogs/12192-villach-1985-and-climate-change.html





Tauranga May Average Afternoon Temperatures 1913-2018

Weather Eye
with John Maunder

The average afternoon temperature in Tauranga in May 2018 was 18.1 degrees C.

In contrast, May 2016 was equal with May 1916 as the warmest May on record, both recording 19.3 degrees.

Temperatures have been recorded in the Tauranga area at several sites during the last 100 years, including the current Tauranga Airport site from June 1990.

It's very common for areas, such as Tauranga, to have experienced different observation sites during the years – and the readings from the earlier sites have been adjusted to the present site using standard climatological procedures.

It's considered the temperature series described here is a fair and true record of what the temperature would have been if the current observation site (of Tauranga Airport) had been used throughout the period.

Traditionally, temperature observations have been recorded with a set of maximum and minimum temperature thermometers.

These record the daily maximum temperature – usually recorded in mid-afternoon – and daily minimum temperature – usually recorded just before dawn.

This analysis of temperatures for Tauranga is for the average daily maximum temperatures.

The graph shows details of the average daily maximum temperatures, called simply ‘afternoon', for Tauranga for May from 1913-2017. May 1964 is not included because of incomplete data.

The long-term average afternoon temperature in May for Tauranga is 16.9 degrees Celsius, ranging from the cool May months of 1936, 1940, and 1997 with an average afternoon temperature of 14.9 degrees Celsius, to the warm May months of 1916 and 2016 both with an average afternoon temperature of 19.3 degrees Celsius, May 2011 with 19.1 degrees Celsius, and May 2007 with 18.9 degrees Celsius.

The graph of the average afternoon temperatures for May shows generally normal variations from May to May.

However, the last 20 May months have been a little warmer than other May months since 1913.

From 1913 to 2018, there have been 14 May months with an average afternoon temperature of 18 degrees Celsius or more, and 11 May months with an average afternoon temperature of less than 16 degrees Celsius.

The value for May 2013 was 18.5 degrees Celsius, which is the sixth warmest on record, and for May 2014 the temperature was 18.4 degrees Celsius – the seventh warmest on record, and May 2016 which was equal first warmest on record.

The 14 warmest May months, in terms of afternoon temperatures, on record in chronological order are: 1916, 1928, 1938, 1950, 1999, 2000, 2003, 2005, 2007, 2010, 2011, 2013, 2014, and 2016.

In contrast, the 11 coolest May months, in terms of afternoon temperatures, on record in chronological order are: 1913, 1920, 1924, 1936, 1940, 1945, 1959, 1967, 1977, 1983, and 1992.

The average afternoon temperature in May during the 49-year period 1914-1962 was 16.7 degrees Celsius, compared with 17.1 degrees Celsius for the 49-year period from 1963-2011.

For further information see https://sites.google.com/site/climatediceandthebutterfly


Tauranga May Rainfalls 1898-2018

Weather Eye
with John Maunder

Apart from the exceptional rainfall of 634 mm in May 2005, the graph shows a small decrease in overall May rainfalls over the last 120 years when two recent adjacent 50-year periods are compared. The rainfall for Tauranga for May 2018 was 71 mm.

Since 1898, there have been 14 May months with a rainfall of 200 mm or more. In chronological order, the wettest May months are: 1899, 1900, 1917, 1925, 1926, 1928, 1949, 1950, 1956, 1961, 1962, 1971, 2005, and 2010.

In terms of dry May months, there have been only nine May months with a rainfall of less than 40 mm.

In chronological order, the driest May months are: 1901, 1918, 1939, 1941, 1978, 1991, 1999, 2007, and 2014.

Of particular significance is the exceptional rainfall in May 2005. I estimated that such a rainfall is likely to occur in Tauranga only about twice in every 1000 years.

This suggests that central government should have had a much more important role in the financial implications of these floods, which affected many areas of Tauranga in May 2005.

For further information see: https://sites.google.com/site/climatediceandthebutterfly/



Tropospheric Temperatures 1979 to April 2018

Weather Eye
with John Maunder

The chart below shows that since 1979, when reliable satellite observations became available, there has been little overall trend in the average tropospheric temperatures, apart from milder/warmer temperatures since about 1997, and two significant warm periods associated with the El Nino events in 1998 and 2015-16

The latest global average temperatures of the troposphere updated to January 2018 - observed from US National Oceanic and Atmospheric Administration satellites – are computed by the University of Alabama at Huntsville in the United States. The data shows variations from the 30 year period 1981-2010.

Since 1979, NOAA satellites have been carrying instruments which measure the natural microwave thermal emissions from oxygen in the atmosphere. The intensity of the signals these microwave radiometers measure at different microwave frequencies is directly proportional to the temperature of different, deep layers of the atmosphere. Every month, researchers at the University of Alabama (Dr John Christy and Dr Roy Spencer) update global temperature datasets that represent the piecing together of the temperature data from a total of fourteen instruments flying on different satellites over the years.

The graph above represents the latest update; updates are usually made within the first week of every month. Contrary to some reports, the satellite measurements are not calibrated in any way with the global surface-based thermometer records of temperature. They instead use their own on-board precision redundant platinum resistance thermometers calibrated to a laboratory reference standard before launch.

The troposphere is the lowest layer of Earth's atmosphere.

It contains approximately 75 per cent of the atmosphere's mass and 99 per cent of its water vapour and aerosols.

The average depth of the troposphere is approximately 17 km in the middle latitudes.

The tropospheric temperature data for 2011 is January 0.0 degrees Celsius, February -0.02, March -0.10, April +0.12, May +0.14, June +0.32, July +0.38, August +0.33, September +0.29, October +0.12, November +0.12, December +0.10 degrees.

The data for 2012 is: January -0.09 degrees, February -0.12, March +0.11, April +0.29, May +0.29, June +0.37, July +0.28, August +0.34, November +0.28, December +0.20 degrees.

The data for 2013 is: January +0.50 degrees, February +0.18, March +0.20, April +0.10, May +0.07, June +0.30, July +0.17, August +0,16, September +0.37, October +0.29, November +0.19, December +0.23 degrees.

The data for 2014 is: January +0.30 degrees, February +0.18, March +0.17, April +0.19, May +0.33, June +0.31, July +0.30, August +0.20, September +0.30, October +0.37, November +0.33, and December +0.33 degrees Celsius.

The data for 2015 is: January +0.20 degrees C, February +0.18 degrees C, March +0.14 degrees C, April +0.07 degrees C, May +0.30 degrees C, June +0.32 degrees C, July +0.18 degrees C, August +0.22 degrees C, September +0.20 degrees C, October +0.32 degrees C, November +0.40 degrees C, and December +0.48 degrees C.

The data for 2016 is: January +0.55 degrees C, February +0.83 degrees C, March +0.73 degrees C, April +0.71 degrees C, May +0.55 degrees, June +0.33 degrees C, July +0.39 degrees C, August +0.38 degrees C, September +0.44 degrees C, October +0.35 degrees, November +0.40 degrees C, and December +0.24 degrees C.

  1. data for 2017 is: January +0.31 degrees C, February +0.35 degrees C, March +0.37 degrees C, April +0.40 degrees C , May +0.47 degrees C , June +0.21 degrees C, July +0.28 degrees C, August +0.41 degrees C, September +0.54 degrees C, October +0.63 degrees C, November +0.50 degrees C, and December +0.30 degrees C.
  2. data for 2018 is January +0.26 degrees C, February + 0.20 degrees C, and March + 0.24 degrees C, April +0.21 degrees C.

The coolest months since 1979 were September 1984, with minus 0.49 degrees Celsius, and November 1984, with minus 0.42 degrees Celsius.

The warmest months were February 2016 with plus 0.83 degrees C, February and April 1998, both plus 0.76 degrees Celsius, and March 2016 plus 0.73 degrees, and April 2016 plus 0.73 degrees Celsius.

The chart shows the El Nino warming in the 1998 period, and 2015-16, and the Mount Pinatubo, volcanic cooling during 1992-1993.

For for information see: https://sites.google.com/site/climatediceandthebutterfly



Tauranga April Rainfalls 1898-2018

Weather Eye
with John Maunder

Monthly rainfalls for Tauranga have been recorded at several recording sites during the last 118 years.

From January 1898 to December 1904, the observation site was described as the Tauranga Harbour, from November 1904 to April 1907 the site was described as simply ‘Tauranga'.From January 1910 to December 1923 the site was Waikareao, in Otumoetai; from January 1924 to September 1940 the site was at 148 Waihi Rd, in Judea; from October 1940 to January 1941 the site was at Te Puna; and from February 1941 to now, the site is Tauranga Airport.

The methodology use in adjusting the older sites to the current observing site is published in the ‘NZ Meteorological Service Miscellaneous Publication' No 180 in 1984.

It is considered that the homogeneous rainfall series described here is a fair and true record of what the rainfall would have been if the current observation site (Tauranga Airport) had been used since 1898.

This should be coupled with the understanding that although standard accepted methodologies have been used, any adjustments are only estimates of what would have occurred if the location of the rainfall records had always been in the same place with the same surroundings and the same or similar recording gauge.

In terms of climate change (such as is it getting wetter or drier, or warmer or colder), the methodology used in computing an ‘official' set of climate observations is very important, as otherwise erroneous conclusions may be drawn.

Rainfalls in Tauranga during the month of April 2013 and April 2014 and April 2017 were all relatively wet, with April 2013 recording 284 mm – the seventh highest April rainfall since 1898 – and in April 2014 the total was 225 mm – the 16th highest April rainfall in the city since 1898.

April 2018 had a rainfall of 140 mm.

The graph shows the range of rainfalls from a high of 383 mm in 1911 to a low of 10 mm in 1958.

The second wettest April was 1948, when 333 mm was recorded; and the second driest was April 2010 with only 12 mm.

The long-term average rainfall for Tauranga for April is 120 mm.

 

Since 1898, there have been 11 April months with a rainfall of 250 mm or more.

In chronological order, the wettest April months are: 1911, 1923, 1935, 1938, 1948, 1959, 1995, 2000, 2001, 2013, and 2017.

In terms of dry April months, there have been nine months with rainfall of 30 mm or less.

In chronological order, the driest April months are: 1898, 1910, 1913, 1919, 1958, 1979, 1984, 2005, and 2010.