Precipitation changes until now

An increase of the maximum length of the periods without precipitation has been observed over the last decades in the south of the country in the winter and in the west in the summer. An increase of the number of days with more than 10 mm/day of precipitation (up to 4 days) has been observed in the north, especially in autumn.

BORA THERESA - ROMANIA

LAZAR EDELEANU ,NAVODARI

ROMANIA

Precipitation is a very important part of climate. Precipitation is the solid, liquid, or gaseous water that falls from the atmosphere to Earth's surface. This includes snow, sleet, hail, rain, and even mist. Changes in the amount of precipitation falling to Earth affect our lives in many ways. Daily human activities, business and industry, agriculture, and the environment all require water. Much of Earth's water ultimately comes from precipitation. Too little precipitation can result in dry soil, shallow streams, and shortages of municipal water supplies.

However, too much precipitation can also have a negative impact on human activities, business and industry, agriculture, and the environment. For example, too much rain or snowmelt (water from melted snow) at one time can lead to flooding. Living organisms, including crops, can drown in floodwaters.

Homes, businesses, even land can be washed away.

Climate change issues / Maysun Taha - Jordan

2.rain, snow, sleet, or hail that falls to or condenses on the ground. "these convective processes produce cloud and precipitation"

Definition

precipitation /prɪˌsɪpɪˈteɪʃ(ə)n/ noun: precipitation; plural noun: precipitations

1. Chemistry the action or process of precipitating a substance from a solution

The different types of precipitation are:

Rain. Most commonly observed, drops larger than drizzle (0.02 inch / 0.5 mm or more) are considered rain. ...
Drizzle. Fairly uniform precipitation composed exclusively of fine drops very close together. ...
Ice Pellets (Sleet) ...
Hail. ...
Small Hail (Snow Pellets) ...
Snow. ...
Snow Grains. ...
Ice Crystals.

Bora Theresa - Romania

Precipitation forms in the clouds when water vapor condenses into bigger and bigger droplets of water. When the drops are heavy enough, they fall to the Earth. If a cloud is colder, like it would be at higher altitudes, the water droplets may freeze to form ice. These ice crystals then fall to the Earth as snow, hail, or rain, depending on the temperature within the cloud and at the Earth’s surface. Most rain actually begins as snow high in the clouds. As the snowflakes fall through warmer air, they become raindrops.

Diana Tirnovanu - Romania

Particles of dust or smoke in the atmosphere are essential for precipitation. These particles, called “condensation nuclei,” provide a surface for water vapor to condense upon. This helps water droplets gather together and become large enough to fall to the Earth.

Anamaria Borta - Romania

A common misconception is that when raindrops fall, they have a teardrop shape. In fact, smaller raindrops (ones that are approximately 1 millimeter (0.039 inches) across) are almost perfectly spherical. Larger raindrops (2–3 millimeters (.078-.118 inches) across) are also round, but with a small indent on their bottom side. They look more like kidney beans when falling to the Earth. Very large rain drops (larger than 4.5 millimeters (.177 inches)) have a huge indent and look more like a parachute. These extra-large drops usually end up splitting into two smaller droplets. The indents on raindrops are caused by air resistance.

Theresa Bora - Romania

Precipitation is always fresh water, even when the water originated from the ocean. This is because sea salt does not evaporate with water. However, in some cases, pollutants in the atmosphere can contaminate water droplets before they fall to the Earth. The precipitation that results from this is called acid rain. Acid rain does not harm humans directly, but it can make lakes and streams more acidic. This harms aquatic ecosystems because plants and animals often cannot adapt to the acidity.

Alina Corduneanu - Romania

Causes for changes in precipitations

Precipitation trends, 1900 to present

red circles reflect increasing precipitations

blue circles reflect decreasing precipitations

Changes

For these reasons, many scientists have been monitoring precipitation trends. That is to say, they have been watching changes in the amount of precipitation falling to Earth. In the last 100 years, precipitation has increased by an average of about 1% over all the land surfaces on Earth. Across the United States, alone, precipitation has increased by an average of about 5% in the last 100 years. Note that this is an average. Some areas of the United States have experienced as much as a 20% increase in precipitation over the last 100 years (see figure above). While other areas have experienced a 20% decrease in precipitation. / Arsaluis Luiza Ripeanu - Romania

Temperature

The leading cause is a change in temperature. Many scientists believe an increase in temperature could lead to a more intense water cycle. The rates of evaporation from soils and water, as well as transpiration from plants, could increase. The amount of precipitation could also increase.

Diana Tirnovanu / Romania

Changes in the water cycle

Predicted changes in the water cycle also differ according to the climate model used. The "business as usual" climate model (described in Remote Sensing: Carbon Dioxide" assumes climate changes based solely on the effects of greenhouse gases. Predictions of changes in precipitation based on this model show an increase in the amount of precipitation falling in the next 100 years (see figure below). Another model includes in its assumptions the effects of sulfates. Sulfates cause a cooling of the atmosphere. Therefore, sulfates can decrease the effects of greenhouse gases on temperature. Models of future precipitation that include the effects of sulfates also show an increase in the amount of rain and snow. However, the increase in precipitation predicted in these models is not as great as the increase predicted in the "business as usual" models.

Alina Cordoneanu/ Romania

The timing of precipitation

Whether or not the amount of precipitation changes, many climate models show that the timing of precipitation will change. Scientists predict that most precipitation in the future will fall during a smaller number of storms that are heavier in intensity. This is because the elevated temperatures will provide more energy in the atmosphere for storm production.

Theresa Bora/ Romania

In recent years, Tunisians have been aware of the phenomenon of floods in autumn and spring and the unusual heat of some summer and autumn days, in addition to the occasional suffering of farmers from unusual precipitation in winter.

Tunisian climate is dominated by natural fluctuations since ancient times and not only in recent years. Tunisia experienced drought in the 1940s in addition to other years because of the lack of rainfall which significantly affected the agricultural seasons in those .

Another example is the abundance of rain in the fall or spring and winter shows that this phenomenon is not new to us, as our parents and grandparents.

Over the last century, our country was characterized by heavy rainfall, whether in autumn, winter or spring, and continues sometimes for a period of time. They were also eyewitnesses to the occasional rainfall for a month throughout winter.

At the time they suffered especially from the drought, the decline of their agricultural crops and the difficulties in providing food. / Tunisian Team

Average Minimum And Maximum Temperature In Tunis (Tunis) In Celsius

The monthly mean minimum and maximum temperatures over the year in Tunis, Tunisia

Temperature

The hot season lasts for 2.9 months, from June 16 to September 12, with an average daily high temperature above 87°F. The hottest day of the year is August 4, with an average high of 94°F and low of 73°F.

The cool season lasts for 4.0 months, from November 23 to March 23, with an average daily high temperature below 67°F. The coldest day of the year is January 20, with an average low of 46°F and high of 60°F.

Annual Weather Averages

August is the hottest month in Tunis with an average temperature of 27°C (81°F) and the coldest is January at 11.5°C (53°F) with the most daily sunshine hours at 11.5 in July. The wettest month is December with an average of 66.8mm of rain. The best month to swim in the sea is in August when the average sea temperature is 26.6°C (80°F).

The hottest Month : August

The most rainy months : Junuary and December

Tunisian Team