AMDAR Observing System

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Volume 15, April 2018

*** Note to reader: Throughout the newsletter, images are usually reduced in size and resolution to fit the newsletter layout - in such cases, the reader can usually click on the image to see the full-size, higher-resolution image on the newsletter website.

Welcome from the Chair of WMO CIMO Expert Team on Aircraft-based Observations (ET-AO)

Dear Reader,

It gives me great pleasure again to write the introductory remarks to this the 15th Volume of the WMO AMDAR Observing System Newsletter.  It certainly has been a busy few months since the last issue! 

The Newsletter’s intent is to inform the readership of the latest news regarding aircraft based observations and associated developments that are providing or will provide enhancements to the global upper air observing networks.

Firstly, I would like to thank the contributors to this Volume for their input and personal enthusiasm for AMDAR.  It is this enthusiasm that undoubtedly has aided the continued expansion of AMDAR and, from a personal point of view, makes working with my peers, colleagues, airlines and aviation industries a pleasurable and satisfying job – especially when we see a successful development come to fruition e.g., addition of an airline to the network. I would also like, on behalf of WMO and the Aircraft-Based Observations Programme, to express grateful thanks to Mr Carl Weiss, who freely provides his time and services as editor of the Newsletter and has again done a great job in collating and editing this edition - thank you, Carl!

As you will see, this Volume encompasses a wide range of topics…  These include reports on established Programmes such as the U.S. WVSS-II, the impact of the LATAM data in South America and improvements to the performance of the numerical weather prediction models.  Also reported are the current developments with airlines for the provision of AMDAR data as well as the collection and dissemination of the ICAO Automatic Data Surveillance – Contract (ADS-C) meteorological reports.  You also will find a report from the WMO Regional Association VI Workshop in Budapest last December as well as an update on the developing, future ICAO and WMO Collaborative AMDAR Programme (IWCAP).

I hope that you find the articles below interesting and informative and please feel free to provide comments and feedback to the authors and editorial team via the contacts list available at the end of the Newsletter.

Stewart Taylor, Chair, CIMO ET-AO and WMO AMDAR Development Officer

Status of Aircraft-Based Observations & AMDAR

The graphic at right shows the smoothed, monthly average of daily observations (single point measurements in space and time, mainly of air temperature and wind speed and direction1, made by an aircraft) transmitted on the World Meteorological Organization (WMO) Global Telecommunications System since 2007 up to March 2018, as contributed by:

- All aircraft and all systems (black);
- AMDAR only (blue)
- From the AMDAR Programme with reports   submitted in binary format (BUFR, red);
- From the AMDAR Programme with reports   submitted in text format (FM42, green); and,
- From ICAO data sources (AIREP and ADS,   magenta).

It can be seen that over recent years, mean daily observations totals of aircraft-based meteorological observations reported have gradually increased and are around or above 800,000 observations per day, with AMDAR observations making up the majority of these at over 700,000 observations per day. The number of observations per day varies quite significantly depending on the number of aircraft deployed by participating airlines, which can vary from day to day, month to month and season to season depending on passenger demand and other factors.

Over the past 18 months, an increase in aircraft-based observations has been evident, resulting from an increase in observations available from the International Civil Aviation Organization (ICAO) Automatic Dependent Surveillance - Contract (ADS-C) system. These observations are made available to WMO Members as a result of a long-standing arrangement between ICAO and WMO in which meteorological information derived from routine aircraft reports supporting international air navigation and air traffic management, can be used to also support meteorological applications - including but not limited to forecasting for aviation.

The observations from the WMO AMDAR observing system are the output from 12 operational AMDAR national and regional programmes in cooperation with some 40 national and international participating airlines, as listed on the WMO website.

The data produced leads to a 24-hour global coverage (31 March 2018) that is depicted in the graphic at left, where less than 5% of available data at varying altitudes are shown. The red coloured points indicate where aircraft are reporting at low altitudes on ascent or descent and the blue where observations are made at high altitudes (usually at or over 35,000 feet) and flying in between airport locations.

[Courtesy of the USA National Oceanic and Atmospheric Administration (NOAA), Earth System Research Laboratory (ESRL) Global Systems Division (GSD), AMDAR Data Display.]

WMO and its Members are grateful to our aviation industry and airline partners for their continued contribution to the WMO Aircraft-based Observing System and the AMDAR Programme. The data that are produced from this collaboration are utilized within many meteorological applications and forecasts, benefiting aviation operations and safety, other application areas and the wider general public.

For more information on aircraft-based observations data statistics visit the WMO website.
For information on the status of reporting of water vapour and turbulence, see other articles in this newsletter.

News on National and Regional AMDAR Programme Developments

WMO and its Expert Team on Aircraft-Based Observing Systems (ET-ABO) monitor progress and assist where possible in the developing national and regional AMDAR and aircraft-based observations programmes. Following is a summary of known and reported activities underway.

WMO Region I (Africa)


In a project under the Weather and Climate Information Services for Africa (WISER) programme, WMO, the Kenya Meteorological Department and Kenya Airways are working on the development of a national AMDAR Programme for Kenya.


Development of the National AMDAR Programme for Morocco is an ongoing project between the WMO, EUMETNET, the Moroccan Meteorological Directorate and the Royal Air Maroc. 

A Data License Agreement (DLA) with E-AMDAR is almost finalized and testing of data from the fleet is in progress. 

Data from the RAM fleets will provide profile information in regions of Northwest, Western and Central Africa and valuable en-route data over the continent.

WMO/E-AMDAR Data Provision over Africa

As reported in Newsletter Volume 12, October 2016, there was a provision for expanded data over Africa with the use of the E-AMDAR B777 fleets of Air France (AFR) and British Airways (BAW). The figure at right shows a snapshot of AFR data coverage (red) and BAW (blue) for a four-day period in March 2018.

This expansion has provided valuable upper-air data over Africa and the Indian Ocean – supplementing the South Africa Regional Programme with South African Airways (SAA) observations.

WMO Region II (Asia)

Hong Kong China

The number of quality-checked aircraft in Hong Kong, China AMDAR programme grew from 9 to 38 in December 2017 and is expected to increase to around 50 this year.  Meanwhile, Hong Kong Observatory continues to collaborate with Cathay Pacific Airways and Cathay Dragon on in-situ turbulence reporting. 

 At the same time, the Observatory is considering an enhancement to the ADS-B receiver software to derive wind and temperature information from Mode S interrogated data around Hong Kong.

Figure 2 shows data coverage of the Cathay Pacific fleets.
Figure 2: Cathay Pacific route coverage
The above only highlights some of the development of Regional AMDAR which will assist in the ultimate goal of achieving global aircraft data coverage.

WMO Region III (South America)


The Argentina AMDAR Programme now produces around 1500 messages on the GTS each day with 6 aircraft now reporting observations.
A new course called “Introduction to AMDAR” is going to be released in May 2018. The course is designed for aviation forecasters and meteorological service and aeronautical decision makers.


Currently DECEA Brazil is developing the first phase of its aircraft-based observations development programme, with the first aim to derive observations via ADS-C reports. The project has now progressed to the point where test messages are being transmitted on the GTS.

WMO Region IV (North America, Central America and the Caribbean)


NAV CANADA and Jazz (operated under Air Canada Express) continue to be the only active AMDAR data contributors to the Canadian AMDAR Programme. Jazz AMDAR CRJ-200 aircraft are being retired and partly replaced by DHC-8-Q400. As of February 2018, 10 aircraft are reporting AMDAR data for an average of 3500 observations per 24 hours. NAV CANADA operates 3 AMDAR-capable aircraft (2xCRJ-200 and 1xDHC-8-100), which are used for unscheduled Flight Inspection at most Canadian airports (approximately 2 annual visits per Canadian airport).

The potential of AMDAR in Canada is currently being evaluated by the Meteorological Service of Canada (MSC) through the engagement of various Canadian airlines.  Potential options for establishing an expanded and sustainable Canadian AMDAR Programme are being investigated. This phased engagement approach is in progress and 6 major airlines have completed the MSC’s AMDAR capabilities survey and results have been reviewed by WMO experts. All AMDAR business models are currently being considered (e.g. arrangements with airlines directly or via data service providers). The MSC is currently analyzing routes (ascents/descents) results per airport and aircraft type en route to user’s validation of results and recommendations. Results of this analysis will lead to the development of a Business Case towards the potential expansion and sustainability of the Canadian AMDAR Programme.

United States of America

The United States continues to procure and distribute AMDAR data from all major US-based carriers and WVSS observations from approximately 135 aircraft operated by Southwest Airlines and UPS. 

Additionally, data from LATAM are also processed by the USA and providing approximately 1400 soundings per day over South America. Because of recent budget developments in the United States, support will be available to continue providing these observations for the rest of 2018 and the first half of 2019. 

This budget support will also permit continued provision of a large increase in data that was first made available in 2014 following the provision of disaster relief funds for Hurricane Sandy. The attached figure illustrates the historically provided US data and the large increase that occurred after 2014, including the LATAM data.  It is hoped that for at least the near-term future budget resources will continue to be available to provide these data, particularly the LATAM data, which constitute a relatively small portion of the US AMDAR budget (~10%) but are over a heretofore data-void region of the globe.

For the remainder of 2018 and 2019, the US AMDAR programme will actively seek to recruit airlines in data void regions within its airspace and adjacent to North America, such as airlines servicing Alaska and Hawaii, with a short-term focus on Hawaiian Airlines.  

The US AMDAR programme is also seeking resources to install WVSS on candidate airlines.  NOAA seeks to do this by forming partnerships with other US weather agencies, such as the Department of Defense.  

The US continues to procure and provide ADS-C en-route data from those airlines serviced by Rockwell Collins. The US is coordinating with WMO and E-AMDAR on possible programme arrangements to obtain ADS-C data from those airlines serviced by SITA, Inc. Success in obtaining these data would approximately double the availability of ADS-C data worldwide.  

WMO Region V (South-West Pacific)


The Bureau is currently testing a new version of AMDAR software for Qantas A330s with improved turbulence reporting. This will shortly be rolled out to the 23 A330-200/300s in the Qantas fleet. These aircraft are used for domestic, high passenger volume flights (Melbourne-Sydney-Brisbane-Perth) and for international flights.

The Bureau is also currently in discussions with Qantas for the possible development of AMDAR software for Qantas B787 Dreamliner fleet.

Discussions are also underway with Airservices Australia (Air Traffic Control authority for Civil Aviation) on a single feed of ADS-B/Mode-S data for all ATC radars.  If achieved, an operational Aircraft Derived Data (ADD) data stream would be provided from these radars for NWP and aviation forecasting.

New Zealand

Work is currently underway on the expansion of the New Zealand AMDAR programme to incroporate reporting from Air New Zealand (ANZ) B777 and B787 aircraft. Discussions are also being undertaken with Lufthansa Technik AG regarding possible future integration of water vapour measurement within the ANZ A320 fleet.

WMO Region VI (Europe)


The E-AMDAR programme is currently formulating its implementation plans for the for the next 5 years, which will see expansion and re-naming as the EUMETNET Aircraft based Observations (E-ABO)  Programme. Within the EUMETNET domain, it is planned to implement an operational Mode-S data service during 2020 and hopefully extending availability of global ADS-C data (oceanic and also over Africa) by obtaining the ADS-C Met reports received by SITAONAIR and making them available on the WIS as quality controlled observations. We shall also be exploring opportunities to reduce data costs through use of the ever-growing availability of satellite broadband communications to/from aircraft.

In the meantime, Aer Lingus has started to provide limited AMDAR data as an initial trial before the expected rollout of capability to their entire fleet during 2018. This will provide much needed profiles to the west of the UK/European region. We will now concentrate on bringing in Turkish Airlines, who have successfully tested AMDAR on different fleet types (to improve SE European coverage) and Royal Air Maroc (to improve coverage in the SW Europe and NW Africa). Improvements to AMDAR coverage in E Europe are also needed.
At present there are unfortunately no firm opportunities to expand humidity observing within Europe. We shall nevertheless continue to build the case for investment based upon impacts and benefits to the Air Transport Industry (ATI).

In parallel, Regional Association VI has provided in-principle approval to develop the IATA-WMO Collaborative AMDAR Programme in the region, so work on a regional implementation plan and business case can begin, for which a WMO RA VI working group still needs to be established.

There is also work continuing with a number of airlines (and Airbus) to develop EDR turbulence reporting, many of which favour use of Electronic Flight Bags (EFBs) to calculate EDR vales, rather than using the on-board processors.


DWD has recently established an agreement with Lufthansa Technik AG, a provider of maintenance, repair, overhaul and modification services, in relation to three areas of possible cooperative activities.

Firstly, to equip one of the smaller airlines within the Lufthansa group with water vapour sensors (WVSS‑II), with 
provision of AMDAR data on this fleet via the satellite connection for the in-flight entertainment instead of ACARS, with the inclusion of reporting of turbulence. Secondly, the porting of satellite-based AMDAR data transmission (turbulence included) successively to other airlines within the Lufthansa group. And, thirdly, the evaluation of the potential use of water vapour measurement as an input to icing warning and de-icing control, based on its algorithmic combination with existing other aircraft parameters, such as air temperature, de-icing devices and weather radar signal.


E-AMDAR has successfully tested AMDAR software on Turkish Airlines (THY).  This development has the potential to provide data on routes westward to western and central Africa, eastern Europe and also to the Middle East and Asia.

Russia and Poland

Following the recent WMO Regional Association VI Workshop (Budapest, December 2017), interest in AMDAR development was shown by both the airlines and meteorological services in Russia and Poland.  Earlier this year, E-AMDAR provided a week-long high frequency trial for the Polish Meteorological Service (IMGW) – this trial highlighted the potential coverage in Poland assuming the Polish airline (LOT) would report at major hub airports.  Follow-up contacts with both countries are planned for the first half of 2018.


There are also ongoing discussions with SATA (the Azores) and Ukranian International Airlines.

ABOP Water Vapor Measurement

Global Water Vapor Measurement Summary

Participating members of the WMO Aircraft Based Observations Programme (ABOP) continue to maintain the collection of Water Vapor Measurements (WVM) through the implementation of the Water Vapor Sensing System (WVSS-II).  Since the last AMDAR Newsletter, the number of WVSS-II equipped aircraft in support of global ABOP operations has returned to the previous levels after the completion of the aircraft fleet transition at Southwest Airlines.  The current worldwide total of ABOP aircraft reporting WVM is 148 aircraft.  These aircraft produce approximately 1,300 vertical profiles daily containing water vapor as well as wind and temperature data for use in numerical weather prediction and all forecast operations.  These in-situ upper air observations continue to be a valuable contribution to the Global Observing System.  Again, RA-IV leads the way in WVSS-II implementations through the U.S. National Oceanic and Atmospheric Administration (NOAA) / National Weather Service (NWS) Public Private Partnership program with Rockwell Collins.  The RA-VI WVSS-II network for EUMETNET AMDAR (E-AMDAR) remains at nine operational aircraft.

Current number of aircraft reporting WVM globally, organized by contributing WMO Region.

The figure at left, courtesy of NOAA/Earth System Research Laboratory/Global Systems Division (NOAA/ESRL/GSD), shows the current global coverage of WVM data from WVSS-II equipped aircraft in a typical 24 hour period.

The Boeing 737-700 configuration of WVSS-II remains the most widely in use with 108 aircraft equipped for WVM reporting.  Eight additional B737-700s have been installed in the U.S. network since the last AMDAR Newsletter.

      24 hours of WVM data from around the world. (Graphic courtesy of NOAA/ESRL/GSD)

Current number of aircraft reporting WVM with WVSS-II, organized by Carrier and Aircraft Type.

U.S. NWS WVSS-II Program Continues Support for ABOP WVM

There are currently 139 WVSS-II equipped aircraft operating in the U.S. network.  The present airline partners reach many nations in RA-IV on a routine
 basis as well as frequent stops in other regions.  Thus, the U.S. WVSS-II network helps support weather forecasting operations for all nations throughout the region, resulting in improved forecast services and increased aviation safety for everyone.  The U.S. WVM network implementation with WVSS-II is a Public-Private Partnership between NOAA/NWS, Rockwell Collins, and partner airlines United Parcel Service and Southwest Airlines.  The figure at right, courtesy of NOAA/ESRL/GSD, shows the RA-IV coverage of ABO data with WVM over a typical 24-hour period.

    24 hours of data from WVSS-II equipped aircraft in the U.S. Network. (Graphic courtesy of NOAA/ESRL/GSD)

E-AMDAR Reporting of WVM with WVSS-II

The nine WVSS-II equipped A321 aircraft operating in the E-AMDAR network with airline partner Lufthansa (DLH) continue to operate as the initial WVM network of E-AMDAR.  With Lufthansa’s main hub at Frankfurt, it produces a frequently sampled set of high quality humidity profiles.  Lufthansa services the majority of nations in RA-VI on a routine basis as well as daily stops in many locations in nearby regions.  The figure below, courtesy of EUMETNET E-AMDAR, shows the RA-VI coverage of ABO data with WVM over a one month period.  In this regard the E-AMDAR WVM network supports meteorological operations for all nations in the region and beyond.

One month (March 2018) of data from WVSS-II equipped aircraft in the E-AMDAR Network.
 (Graphic courtesy of EUMETNET E-AMDAR)

Aircraft-based Turbulence Observations Status within AMDAR

There are two atmospheric turbulence intensity metrics currently in use by the AMDAR community.  The first metric is eddy dissipation rate (EDR).  MacCready (1964) first suggested the use of EDR as a measure of turbulence intensity.  It is particularly useful operationally since EDR along the vertical direction is proportional to the RMS (root-mean-square) vertical acceleration experienced by an aircraft for specific flight conditions (MacCready 1964; Cornman et al. 1995).  Further, EDR has been adopted as the standard metric for atmospheric turbulence reporting by the International Civil Aviation Organization (ICAO) (2001).1

Currently, over 950 aircraft report EDR worldwide with an average of approximately 60,000 reports per day.  The significant increase to the numbers since autumn of 2017 are due to the deployment of EDR software by Southwest Airlines onto almost 700 B737NG aircraft, as well as the deployment by United Airlines onto 15 B777s.  The EDR software is now running on B737NG, B767-300/400 and B777 aircraft.  Work is underway in collaboration with Delta, Qantas and Lufthansa Airlines to deploy it on Airbus aircraft starting with the A321 and A330 airframes.

                                                                                          Figure 1: Locations of all EDR reports from 2018-02-26

The second metric, derived vertical gust (DEVG), is defined as the instantaneous vertical gust velocity which, superimposed on a steady horizontal wind, would produce the measured acceleration of the aircraft.  The effect of a gust on an aircraft depends on its mass and other characteristics, but these factors can be accounted for so that a gust velocity can be calculated which is independent of the aircraft.2  More than 220 aircraft report DEVG worldwide averaging about 20,000 reports daily.  These numbers are based on an analysis of AMDAR data from The U.S. National Centers for Environmental Prediction’s (NCEP) Meteorological Assimilation Data Ingest System (MADIS).  A large fraction of the DEVG data appears under one tail number, which is unrealistic.  Therefore the number of aircraft reporting DEVG is a substantial underestimate.

                              Figure 2: Locations of all DEVG reports from 2018-02-26

The figure above shows the locations of all DEVG reports from 2018-02-26.  There is software-based logic implemented on many aircraft that limit reporting of DEVG in some regions at certain altitudes (e.g., Europe).

These maps illustrate the need for expansion of aircraft-based turbulence observations in many areas of the globe.  WMO continues to work with its Members and their respective national airlines to increase aircraft-based turbulence observation coverage.

WMO and its Members express gratitude to our aviation industry and airline partners for their continued contribution to the WMO Aircraft-based Observing System and the AMDAR Program.  The data produced from this collaboration are utilized within many meteorological applications and forecasts benefiting aviation operations and safety, other application areas and the wider general public.

For more information on aircraft-based observations data statistics visit the WMO website.
Gregory Meymaris, National Center for Atmospheric Research

1 From EDR IP
2 From Aircraft Meteorological Data Relay (AMDAR) Reference Manual, WMO-No. 958 https://www.wmo.int/pages/prog/www/GOS/ABO/AMDAR/publications/AMDAR_Reference_Manual_2003.pdf

WMO-IATA Regional Workshop on AMDAR for Eastern Europe Budapest, Hungary

In cooperation with the Hungarian Meteorological Service (Országos Meteorológiai Szolgálat, OMSZ) and the EUMETNET E-AMDAR Programme, a WMO-IATA (International Air Transport Association) Regional Workshop on AMDAR for Eastern Europe was held 7 to 8 December 2017 at the headquarters of OMSZ in Budapest, Hungary.  This was the first AMDAR workshop jointly organised by WMO and IATA under the WMO-IATA Working Arrangement on AMDAR Collaboration.
Twenty-seven participants attended the workshop including representatives from both the aviation industry and regional NMHSs.  The purpose of the workshop was to inform regional WMO Member NMHSs about the operation of the WMO AMDAR Programme.  Another aim of the workshop was to show regional airlines and other aviation-related organisations the benefits of AMDAR to aviation (improved weather forecasts and services to aviation meteorology).

The proceedings were opened by Dr. Kornélia Radics, Director of OMSZ and Permanent Representative of Hungary with WMO.  Dr. Radics was pleased to host the WMO AMDAR workshop noting that, like many other NMHSs, OMSZ has a need for additional high-quality upper air observations to supplement data available from conventional observing systems.  OMSZ, through its interaction with the Air Transport Industry, has recognized the need for more upper-air observations to support improved products and services for aeronautical meteorology.  These observations include the wider implementation of water vapour measurement.   In concluding, Dr. Radics wished all participants a successful and instructive workshop.

The workshop programme included a series of presentations by WMO-, E-AMDAR- and IATA-invited speakers spread over six sessions interspersed with periods for questions and open discussions.

The workshop participants were informed about what AMDAR is and its overall value.  Also, the current status of the WMO AMDAR programme was presented underscoring that global coverage was still a concern.  Data sparse areas that include countries where national airlines potentially could contribute to the AMDAR programme were featured.  Eastern Europe in particular has been identified as a region where airline participation in AMDAR should be expanded in order to increase the near-real time reporting of aircraft-based observations.  These additional data would benefit both the meteorological community and airline industry through improved forecast services and more efficient and safer airline operations.  Participants were referred to the availability of on-line WMO documentation and guidance on all AMDAR aspects, in particular to the WMO publication No. 1200, Guide to Aircraft-Based Observations.

The participants were informed about the benefits of the use of AMDAR data to airlines and the wider aviation industry.  Several studies showing  the positive impact of AMDAR data in improving the accuracy of forecasts and meteorological services which led to more efficient airline operations and to improved flight safety were highlighted.  Reference was made to the ICAO (International Civil Aviation Organization) regulated requirements for aircraft reports (including meteorological information) and it was stated that AMDAR observations produced during ascent and descent  should be considered as a valuable and beneficial supplement to the ICAO aircraft reports.

With reference to the WMO-IATA Working Arrangements on AMDAR Collaboration, the audience learned about the IATA and airlines roles in the AMDAR programme.  In showing real examples, it was made clear that AMDAR data could play an important and decisive part in optimising airline operations and in the reduction of general aviation weather related incidents.  IATA is willing to support the expansion of the AMDAR programme by encouraging more airlines to participate through AMDAR promotion.  Education and the commercialization of AMDAR data to benefit the participating airlines are important issues to IATA.

The participants also were shown how AMDAR data were used by OMSZ in their Limited Area Model and in their 3DVAR assimilation system.  As a result, special products in support of their aeronautical meteorology services have been developed.

Practical examples supporting the benefits of AMDAR data were provided by representatives from the airline industry and from  The Met Office, the national meteorological service in the United Kingdom,  which collaborates with Air traffic Management at London Heathrow.

Since good quality and timely turbulence information can be critical to airline operations, plans for the development of a global turbulence repository also were presented and discussed.  Other relevant topics covered included the use of AMDAR information and technologies.  How best to visualize AMDAR data and the technical aspects of developing an AMDAR programme were featured areas.  This was followed by a presentation on the current status of the European E-AMDAR programme, including a vision how to optimize the AMDAR data coverage by expanding the programme into eastern Europe.  To achieve this expansion, the development of a Regional Implementation Plan for AMDAR (A-RIP), supported through collaboration by the potential interested WMO Member States, was necessary.

Workshop discussions with and among the participating NMHS representatives revealed that there was general interest in developing new national AMDAR programmes and that a few countries had commenced investigating the potential for development, or were already in discussions regarding their participation in a regional programme.

Towards the closure of the workshop, the outcome, key issues and actions were identified.

The final workshop report can be found at the WMO CBS OPAG-IOS website

Frank Grooters, Member ET-ABO

Progress on IATA-WMO Collaboration on AMDAR

As reported in Volume 14 of the Newsletter, in July 2017, WMO entered into a working arrangement with the International Air Transport Association (IATA) on the operation of the global Aircraft Meteorological DAta Relay (AMDAR) observing system. 
Under this working arrangement, the two organizations have agreed to discuss and determine how they might together, in the future, collaborate on the expansion and enhancement of AMDAR in pursuit of mutual benefits to both the meteorological and aviation communities.

Since the working arrangement was formed the WMO Commission for Basic Systems (CBS), Expert Team on Aircraft-Based Observing Systems (ET-ABO) has been working with key members of the IATA Secretariat to develop the Concept of Operations for the IATA-WMO Collaborative AMDAR Programme, for which an initial draft was developed in December 2017. Under the Concept of Operations for the IATA-WMO Collaborative AMDAR Programme (IWCAP) the following are the key aspects of the collaboration:
  • Each WMO Regional Association (RA) would be responsible for establishing and maintaining regional requirements for AMDAR observations, primarily based on national member requirements and resourcing to pay for observations and support for the programme operation;
  • IATA and WMO would develop a cost framework for supporting the operation and development of IWCAP to meet national and regional requirements for observations;
  • IATA and WMO would jointly manage funds to support the IWCAP and reimburse airline partners for the costs of the programme development and provision of observations on the WIS; 
  • RAs would operate and maintain Regional Data Processing Centres and support planning activities and data and quality management operations through the establishment of regional working groups.
Given the successful operation of the EUMETNET/E-AMDAR programme on a regional collaborative basis, a decision was made in February 2018 by the WMO Regional Association VI (RA VI, Europe) that, subject to IATA and WMO entering into a formal collaboration on AMDAR, based on agreement and a decision by WMO Congress in mid-2019, RA VI will compile its requirements for AMDAR observations by the end of 2018, with a view to beginning development of the WMO Region VI AMDAR Programme under the IATA-WMO Collaboration in January 2019 and potentially beginning operation of the programme in January 2020. After this and on a (WMO) region by region basis, the program would gradually migrate to this more regionally and centrally-based mode of operation, supported more actively by the aviation industry under the leadership of IATA.

Meanwhile, IATA and WMO, through CBS will shortly establish a task team to be responsible for the finalisation of the proposed Concept of Operations, the proposed Terms of Reference of the collaboration and the draft Implementation Plan for Establishment of the IATA-WMO Collaborative AMDAR Programme to enable WMO and IATA members to understand and support the collaboration.

AMDAR Data Find Multiple Uses in the Hawaiian Islands

AMDAR data have been found to benefit an increasing number of weather forecasting applications over the last twenty years.  While the majority of these are from continental locations, National Weather Service meteorologists responsible for the islands of Hawaii have found the data to be very useful in forecasting convection, heavy rain, low-level wind shear and turbulence.  The recent large number of low-cost flights from the continental United States to Hawaii has resulted in over fifty AMDAR soundings each day.

AMDAR soundings to Lihue, Kalului, Kona, Honolulu now complement the NWS radiosondes at Lihue and Hilo.

The map to the left shows about fifty AMDAR soundings of wind and temperature for the twenty four hour period ending around 1400UTC April 5, 2018.

Convective Instability:  AMDAR temperature soundings help meteorologists determine stability of the atmosphere by the presence or lack of a mid-level temperature inversion that can inhibit the formation of thunderstorms.  The determination of stability closer to the surface is important in forecasting the development and inland movement of sea breezes, which often help produce showers and thunderstorms.

The NWS staff in Honolulu used AMDAR data, in conjunction with radiosonde and satellite data, to determine that the temperature inversion that had inhibited convection had been overcome, setting the stage for showers and thunderstorms and heavy rain.  Their area forecast discussion from the afternoon of February 17, 2018 follows.

Area Forecast Discussion
National Weather Service Honolulu HI
339 PM HST Sat Feb 17 2018

Moist and unstable conditions are in place across the eastern half
of the state this afternoon. The afternoon Hilo sounding, recent
aircraft data from Kona and Kahului, and satellite imagery show no
inversion and ample precipitable water (PW) values of 1.25 to 2
inches. That said, conditions remain ripe for heavy rainfall
over the entire eastern half of the state, and a Flash Flood Watch
remains in effect, as well as a Winter Weather Advisory for the
high summits of the Big Island.

Rather dry conditions have managed to hang on over the western
half of the island chain so far today, though instability is
increasing. Recent aircraft data out of HNL and Lihue and
satellite imagery showed the low level inversion eroding and
precipitable water values creeping up.

Low-level Wind Shear:  AMDAR wind data show environments with directional and speed shear which can be conducive to low-level wind shear and turbulence.  The NWS Honolulu meteorologists used AMDAR wind data to forecast low-level wind shear on the afternoon of October 21, 2016.

Area Forecast Discussion
National Weather Service Honolulu HI
355 PM HST Fri Oct 21 2016
Radar VAD wind profiles and AMDAR soundings from Honolulu/Lihue/Kahului show 30 knots of wind within a few thousand feet of the surface. Inversions remain weak and elevated, but winds this strong should still support turbulence in the lee of the mountains and an AIRMET is in effect for moderate low-level turbulence. The turbulence threat will increase tonight as the inversion lowers and low-level winds remain just as strong.

An AMDAR sounding from Honolulu during the afternoon of October 21, 2016 shows east northeast winds at 31 knots at 1640 feet MSL and nearly calm winds at the surface.

AMDAR soundings from the Bahamas, Philippines, Virgin and Canary Islands, Mauritius and other islands with commercial airports should provide meteorologists with similar opportunities to improve forecasts of sea and land breezes, convection, turbulence and low-level wind shear.

Richard Mamrosh, U.S. National Weather Service, Green Bay, Wisconsin

What a Difference a Year Makes: The Impact of Enhanced AMDAR Reporting over South America

Introduction:  While the previous three notes in this series have focused on the value of AMDAR moisture observations, this note documents the impact that enhancing AMDAR observations (primarily wind and temperature reports) can have on Numerical Weather Prediction (NWP) performance both globally and in specific areas where these aircraft observations have historically been quite sparse.  Although assessments were done for several different geographical areas, this article focuses on two areas:  1) Global impacts due to enhanced en-route and profile reporting and 2) impacts in the vicinity of South America due to a major increase in observations in that area south of the equator.

Background:  Previous studies have shown that AMDAR wind/temperature observations now constitute the 3rd to 5th most important data set for most global NWP systems.  In areas of ample reports, they have become the single most important data set for use in shorter-term regional NWP applications.  Automated aircraft reports provide the most cost-effective data source for improving NWP, being more than five times more cost-effective than any other major-impact observing system.  They also present an economical alternative for obtaining tropospheric profiles both in areas of diminishing conventional observations and as a supplement to existing data sets both in time and space.

Regional impacts from observations over the U.S. have been particularly impressive due primarily to the large number of both en-route flight level reports and vertical profiles taken during ascent/descent.  A question that has remained unanswered is whether similarly large impacts can be replicated in other parts of the world through increased reporting.  Support for a recent increase in AMDAR observations provided by the U.S., described in the October 2017 volume of the AMDAR Newsletter, has provided the opportunity to conduct such a study.  Specifically, three categories of wind/temperature observations were increased: a small increase in global en-route data, a larger increase in en-route and profile data over the U.S. and a major increase in flight-level and ascent data over South America.  These increases are apparent in the coverage changes noted in Figure 1.

Figure 1: Comparison of Global AMDAR data coverage for 24 hours on 20 Sept. 2016 (left) and 20 Sept. 2017 (right). Sub-area used to evaluate impact of increased South American observations is outlined. Color bar between panels indicates altitude of aircraft at time of AMDAR reports. Note the substantial increase in data density over South America and along Northern Hemisphere oceanic routes.

During the period from November 2016 to November 2017, the number of AMDAR observations increased by over 18% globally and nearly 12% over the U.S.  Over South America, the number of reports increased by a factor of over 18 with more than 85% of these reports in aircraft ascent profiles.  Although this increase was very large, the number of new observations is equivalent to only about 10% of the observations taken over the continental U.S., where AMDAR observations provide ~50% of the error reduction in the U.S. Navy’s global NWP system.

Methodology:  In order to provide more specific insight into the value of assimilated AMDAR observations in operational models, an evaluation of the impacts of all data sets used in the operational U.S. Navy global analysis and forecast system (NAVGEM, Navy Global Environmental Model, Hogan et al. 2014) was conducted using Forecast Sensitivity Observation Impact (FSOI) methods (Langland and Baker 2004).  FSOI values are computed for each observational component of the operational NAVGEM runs.  When summed over a specified period, they can be used to determine the relative importance of each specific data source in reducing the 24-hr forecast error, measured as a percentage of the total moist energy error norm.

NAVGEM impacts were measured for two separate month-long periods, November 2016 and November 2017.  In addition to minimizing inter-annual variations in weather variations that could affect model performance, this interval was chosen to assure that any differences in observational data impacts were due predominantly to changes in the availability of AMDAR reports and not to changes in the NWP assimilation and modeling systems, which were unchanged throughout. It should be noted both that historically, the impact of AMDAR data in the NAVGEM system has been less than that in other major global NWP systems and that, as has been the case for other AMDAR data implementations, negligible additional quality control change was needed.

Global Impacts:  Figure 2 shows the relative impact of the 13 major data types used in the NAVGEM runs during November 2016 and November 2017, before and after the aforementioned increases in AMDAR reporting. Throughout the period, seven data types account for more than 90% of the impact to the NAVGEM system. The impacts of the three satellite types (infrared radiances, microwave radiances and geostationary winds) that contribute most to the NAVGEM short-range forecast improvement change only slightly, as should be expected from previous global tests. The impacts of the three next-most important observation types, however, change substantially with the inclusion of additional AMDAR reports. The relative importance of AMDAR data increases by nearly 2.5% to become almost equal to surface and radiosonde observations. At the same time, the impact of radiosondes decreased by nearly 2% and surface observations declined by more than 0.5%. These results point toward the increased importance of AMDAR observations taken throughout the day (especially those made as vertical profiles) relative to conventional synoptic-time observations.

Figure 2:  Comparison of impact on global forecasts of 13 major types of observations used in the NAVGEM NWP system during Nov. 2016 (A) and Nov. 2017 (B).  Changes in impacts from 2016 to 2017 are isolated in panel C; with positive %s indicating increased error reduction in short-range forecasts.  Note that the AIRCRAFT category includes both AMDAR and AIREP data with the small amount of AIREP data providing a negligible impact of only 0.1%.

South American Impacts:  By contrast, changes were expected to be larger over South America due to the extremely large increase in AMDAR reports, especially ascent profiles, across this previous AMDAR data sparse region.  As shown in Figure 3, the changes in the relative importance of the six most regionally significant data sets is substantially altered by the infusion of 18 times more AMDAR reports throughout the day during this summertime period.  AMDAR data moved from being the 6th most important data set to becoming the single most dominant data source, providing more than 27% of the impact on NAVGEM forecasts and replacing radiosonde observations as the prominent regional data set by a factor of two.  As with the global tests described above, surface observations also take on a less important role.  Unlike the global results, however, increasing AMDAR observations over the South American land mass also decreases the impacts of the three primary satellite data sets.  Similar changes were also found in September 2017.

Figure 3: Comparison of impact of 13 major types of observations from the Southern-Hemisphere South American region used in NAVGEM global forecasts during Nov. 2016 (A) and Nov. 2017 (B).  Changes in impacts from 2016 to 2017 are isolated in panel C with positive %s indicating increased error reduction in short-range forecasts.

The degree to which the increase in AMDAR observations, especially vertical profiles, heightened their value in this NWP system is truly noteworthy.  Although observation impact in this region is only half of that produced by the 10 times larger number of AMDAR reports collected over the U.S., these results clearly show the potential for AMDAR observations to improve NWP performance in other parts of the globe, all at a fraction of the cost of enhancing other conventional surface-based or satellite observing systems.  Indeed, the cost of acquiring the additional soundings over South America was about 10% of the total cost of all AMDAR observations procured by the U.S., yet their availability over a heretofore under-observed region shows great utility in expanding forecast skill.

Summary:  This note documents how enhancing AMDAR wind and temperature reports can improve NWP performance by reducing short-range forecast errors both globally (due to enhanced en-route and profile reporting) and over South America (due to a large increase in observations south of the equator there).  During the period from November 2016 to November 2017, the number of AMDAR observations increased by over 18% globally and by nearly 12% over the U.S.  Over South America, the number of reports increased by a factor of over 18 with more than 85% of these reports made as profiles during aircraft ascent.  Tests of the relative impacts of different data sources were performed using an unchanging version of the U.S. Navy global analysis and forecasts system (NAVGEM), a model that historically has used fewer AMDAR observations than other models from other global NWP centers.

Globally, the relative importance of AMDAR data increases by nearly 2.5%, while the impact of radiosondes decreases by nearly 2% and surface observations by more than 0.5%.  Over South America, however, the injection of many more reports extending throughout the troposphere moved AMDAR data from being the 6th most important data set to becoming the single most dominant data source in the region, providing more than 27% of the impact on NAVGEM short-range forecasts, nearly double the impact of radiosonde observations in this area.

Although improvements attributable to AMDAR observations continue to be concentrated in regions where data coverage is greatest, similar advancements are expected in other areas as spatial and temporal coverage of the reports increases globally.  Inclusion of WVSS-II moisture observations should make these impacts even larger.  Increased AMDAR reporting should be particularly important both in areas where the continuation of upper-air observing programs is under budgetary threat and in forecast situations where additional observations are needed to fill the time and space gaps between once- or twice-daily radiosonde launches.

Ralph Alvin Petersen, University of Wisconsin-Madison, Cooperative Institute for Meteorological Satellite Studies (CIMSS)
Patricia Pauley, Marine Meteorology Division, Naval Research Laboratory

WMO AMDAR Observing System Contacts

WMO CBS Expert Team on Aircraft-based Observing Systems Contacts


Mr Curtis Marshall (USA)
Tel : +01 301 472 9244 

Mr Abderrahim Mouhtadi (Morocco)
Tel: +212 522 654910
Email: abderrahim.mouhtadi@gmail.com
WMO AMDAR Observing System Newsletter Editor

Mr Carl Weiss (USA)
Email: ceweiss1949@gmail.com

WMO Scientific Officer, Aircraft-based Observations

Mr Dean Lockett (Switzerland)
Tel: +41-22-7308323
Email: dlockett@wmo.int