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Volume 6, October 2013

Welcome from the Editor

Dear Reader,

Welcome to the sixth edition of the AMDAR Newsletter issued by the WMO AMDAR Observing System. The past several months have seen many changes in the AMDAR programme, most notably the integration of the former Panel’s governance and activities into the formal WMO structure. The former AMDAR Panel has evolved into two teams, an Expert Team on Aircraft-based Observing Systems (ET-ABO) within the WMO Technical Commission Basic Systems (CBS) and a Task Team on Aircraft-based Observations (TT-AO) under the Commission for Instruments and Methods of Observation (CIMO). It is envisioned that under this structure, the AMDAR programme will continue to coordinate and lead the expansion and enhancement of the global aircraft-based observing system as an operational component of the WMO Global Observing System.

This newsletter is an important tool in keeping stakeholders as well as interested parties in the meteorological and aviation communities updated about news and information concerning AMDAR and aircraft-based observations.

In this edition, the articles cover a wide variety of aircraft observation topics ranging from the importance of the data to the aviation industry to plans for global and regional expansion and from data usage to improve icing forecasts to onboard software specifications.  Also included is a summary of the first ET-ABO meeting. I hope you find these articles both interesting and informative.

The Chairs of ET-ABO and TT-AO and their members, the WMO Scientific Officer and the Newsletter Editor welcome any questions or comments on the global AMDAR programme and, in particular, any interest in the development and coordination of new national and regional programmes. Contact details are available at the end of the newsletter.


Carl Weiss, Training and Outreach Coordinator and Newsletter Editor

First Session of the Expert Team on Aircraft-Based Observing Systems

The Expert Team on Aircraft-Based Observing Systems (ET-ABO) is one of two WMO expert teams that are jointly responsible for guiding and managing the programmatic aspects of aircraft-based observations and the AMDAR Observing System.

ET-ABO is a team positioned within the Commission for Basic SystemsOpen Programme Area Group on Integrated Observing Systems and met for its first session over 10-13 September at the WMO Secretariat Headquarters in Geneva.

The 25 attendees, some among them participating via web conference, discussed and made recommendations on a great variety of actions and work plans of the team, which have been inherited and taken up in cooperation and collaboration with the WMO Commission for Instruments and Methods of Observation, Task Team on Aircraft-based Observations (TT-AO), subsequent to the 15th and final WMO AMDAR Panel Meeting (November 2012).

The Agenda for the Session included reports on the work performed by the Aircraft-Based Observations Programme (ABOP) Leadership Group over 2013, the status of the operational and developing national and regional AMDAR programmes and also on the status of other aircraft-based observing systems. The session reviewed the status and progress of the actions in the ET-ABO Work Plan 2013-2014, including the allocated budgets and the financial status of the AMDAR Trust Fund.

In Breakout Sessions small groups discussed, reviewed and proposed amendments to the ABOP Strategy and Implementation Plan, prepared and presented by the AMDAR Development Officer, Mr Stig Carlberg.

Further agenda items included activities of the team related to Training and Outreach, ABO contributions to Polar Observations and the need for strengthening the collaboration with relevant bodies in the aviation industry. 

Other scientific and technical issues associated with the ABOP will be discussed in the first session of TT-AO, scheduled for the first quarter of 2014. Over the coming months, the ET-ABO will continue to undertake its work programme while monitoring and supporting the operational aspects of the ABOP and AMDAR. ET-ABO expects to meet again for its second session in 2015.

A detailed report of the First session of the Expert Team on Aircraft-Based Observing Systems can be found on the CBS OPAG-IOS web site.

Mr Frank Grooters, Chair of the Expert Team on Aircraft-Based Observing Systems

Aircraft-based Observations Output & Coverage

The graphic at right shows the smoothed, monthly average of daily observations (single point measurements made by an aircraft in space and time) transmitted on the World Meteorological Organization (WMO) Global Telecommunications System since 2007 up to September 2013, 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 in recent months, total aircraft-based meteorological observations levels have climbed to well over 450,000 observations per day, with AMDAR observations making up the vast majority of these at at around 435,000 observation per day over September 2013.

The rapid growth shown in the programme over the past 2 years is chiefly due to expansion of the USA AMDAR (MDCRS) programme, with the participation of Alaska Airlines and Southwest Airlines.

The data produced leads to a 24-hour global coverage (June 30, 2013) that is depicted in the graphic at left, where less than 20% of available data at varying altitudes are shown, 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 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 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 public.

For more information on aircraft-based observations statistics visit the WMO website.

Global and Regional Plans for the Aircraft-Based Observing System

Over 2013 much work has been undertaken by WMO in developing the Aircraft-Based Observations Programme Strategy and Implementation Plan to 2025 including the Development and Expansion of AMDAR (A-SIP). 

The strategy is relevant to WMO Members and partner organizations that currently, or will in the future operate aircraft-based observing systems or contribute to the generation and delivery of data from such systems through the WMO Information System (WIS).

The global actions relevant to aircraft-based observing systems, which essentially form the basis for the aims and objectives for the development of these systems are described in the WMO Commission for Basic Systems Implementation Plan for the Evolution of Global Observing Systems (EGOS-IP).

These actions are summarized as:
  1. Improve AMDAR Coverage - especially over and within RA I (Africa) and RA III (Latin America).
  2. Extend coverage of existing programmes outside national boundaries and extend optimization capability.
  3. Work towards extension of AMDAR into aviation standards and systems (avionics and airframes)
  4. Validation and implementation of water vapour measurement
  5. Implementation of turbulence and icing capability
  6. Extend AMDAR to aircraft operating at the regional scale and regional airports.
These actions will be implemented through a set of Core Activities. For each of these Core Activities tasks and sub-tasks have been defined and priorities and timelines have been proposed. As mentioned in the first article of the newsletter, the document was presented to the recent meeting of the WMO Expert Team on Aircraft-Based Observing Systems (ET-ABO) and members were invited to provide their review and comments by the end of October.

In parallel with the development of the global strategy and implementation plan (A-SIP) a planning template was designed and presented to ET-ABO to assist in the development of Aircraft-Based Observations Regional Implementation Plans (A-RIP). The template will assist the National AMDAR Focal Points in the WMO Regions I – VI to work with their respective WMO Regional Associations in developing regional plans and thus stimulating regional cooperation and development of aircraft-based observations. The aim is to have these regional plans integrated into the Regional WIGOS Implementation Plans.

Mr Stig Carlberg, AMDAR Development Officer

Why Aircraft-based Meteorological Observations are Critical to the Aviation Industry

Like many of the modern public or government-initiated success stories, the development of the Aircraft Meteorological DAta Relay (AMDAR) observing system has relied and thrived on what has come to be known as Public Private Partnerships (PPP) between governmental meteorological and hydrological services (NMHS) and their airline partners.

For these partnerships to happen and to work, there has to be a demonstrable benefit to both parties and, given the government involvement, a benefit also to society and the public.

While the idea of using the aircraft platform as a means for making meteorological and other scientific atmospheric measurements is nearly as old as aviation itself, it has only really been since the late 1980s that the current concept of the AMDAR system has truly flourished as an operational programme sanctioned by WMO. Now 
producing nearly half a million observations per day of temperature, winds and, increasingly, humidity in support of the WMO Global Observing System - GOS - (see Figure 1 at right), meteorologists that make use of this data, in a range of weather forecasting applications, are fully appreciative of the critical and significant benefit that it provides to meteorology.

The great benefit of AMDAR data in particular to meteorology, is the fact that the data are derived according to specific meteorological requirements, so that the meteorological parameters measured are reported at a high frequency during the take off and landings of participating aircraft. What this means is that the aircraft provides a "meteorological snapshot" of the atmosphere on a vertical trajectory, in a very similar way to which balloons bearing meteorological radiosondes do. This generation of vertical profiles by AMDAR aircraft certainly makes the programme useful; but there are three elements of the AMDAR observing system which make it especially valuable:
  1. AMDAR wind and temperature data have been shown to be similar in data quality (i.e. accuracy or uncertainty of measurement) to that of radiosondes;
  2. The measurement sensors and systems on the aircraft are able to produce this accurate data at a very high rate or frequency of measurement, thus providing very fine detail within the vertical profiles; and
  3. Owing to the frequency at which aircraft are landing and taking off from airports, these vertical profiles can be produced on at least a 3-hourly basis at many airport locations.
It is these features of the AMDAR observing system that have led forecasting meteorologists to provide testimony that these data are very valuable and useful and provide significant improvement to applications for monitoring and prediction of weather systems and phenomena such as:
  • Surface and upper air forecasts of wind and temperature;
  • Thunderstorm genesis, location and severity;
  • Wind shear location and intensity;
  • Low cloud formation, location and duration;
  • Fog formation, location and duration;
  • Turbulence location and intensity;
  • Jetstream location and intensity;
  • Precipitation amounts and rates; and,
  • Conditions leading to aircraft icing.
Pilots and airline flight and dispatch managers will be the first to understand that it is these very phenomena that impact greatly on airline operations, efficiency and safety - each of which are critical to the financial bottom line of the airline! And so it is this improved ability of meteorologists to monitor and predict these weather phenomena that provide the first conclusive evidence that the AMDAR programme provides an extremely valuable benefit to the aviation industry.

In fact, in the USA, a Research, Engineering and Development Advisory Committee; Report of the Weather-ATM Integration Working Group, October, 2007 made the following conclusions from their study:

"Weather accounts for 70% of all air traffic delays within the U.S. National Airspace System (NAS)."


"A key finding, based on an analysis of several 2005-2006 convective events, is that as much as two-thirds of the weather related delay is potentially avoidable.“

If we put these findings together with these facts from the Congressional Joint Economic Committee report, Your Flight Has Been Delayed Again; May 2008:
  1. The total cost of domestic air traffic delays to the U.S. economy was as much as $41 billion for 2007.
  2. Air-traffic delays raised airlines' operating costs by $19 billion.
  3. Delays cost passengers time worth up to $12 billion.
  4. Indirect costs of delay to other industries added roughly $10 billion to the total burden.
We can therefore see that the financial interests of airlines are indeed well-served by their contributing to any efforts to improve weather forecasting ability that can and will reduce these costs - and not only to the aviation industry but to the community at large. 

As has been highlighted in a previous article in Volume 4, Summary of Recent Studies on the Impact of AMDAR data in NWP Forecasts (Petersen), meteorologists are able to use modern numerical weather prediction (NWP) systems to precisely quantify the benefits of aircraft-based observations and have determined that these observations are second only to high-volume satellite data in impact on NWP systems (see Figure 2 at right). Quantitatively, AMDAR and other aircraft-based observations generally provide an improvement in forecasting ability through a reduction in NWP forecast error of up to 15-20%.

Figure 4:  Impact of various different data sets on accuracy of 24-hour ECMWF forecasts (Based on Radnoti et al, 2010)

So, putting all these facts together, it is very clear that airlines participating in the AMDAR programme are not only benefiting meteorology and, as a result, the public generally, they are also clearly contributing to the efficiency and safety of the aviation industry and their own operations.

In future articles, we will look at how participating airlines can gain even greater advantage through better and more integrated use of AMDAR data and weather information in their flight operations.

For more information on the AMDAR programme and requirements for participation in it, see the WMO Website

AMDAR Onboard Software specification published

WMO is pleased to inform Members, aviation partners and readers that the newly developed AMDAR Onboard Software Functional Requirements Specification (AOSFRS), Version 1.0 has now been formally published and will be maintained in the future as a WMO Commission for Instruments and Methods of Observation (CIMO), Instruments and Observing Methods (IOM) Report.

The specification, IOM Report No. 114, can be accessed from the CIMO IOM Report series and 
is also available via the AMDAR Resources area.

As the Introduction by Professor Bertrand Calpini, President of CIMO states: This document provides a functional specification for AMDAR onboard software, which can be utilized by avionics software developers to build avionics software applications for AMDAR that will efficiently meet WMO standards and requirements for reporting of meteorological data from the aircraft platform utilizing aviation communications protocols and infrastructure. 

The WMO CIMO Task Team on Aircraft-based Observations (TT-AO) now intends to work towards the harmonization of the AOSFRS with the specification of the Meteorological Report within the AEEC 620-7 Data Link Ground System Standard and Interface Specification (DGSS/IS).

TT-AO also intends to approach avionics vendors for discussions regarding development of AMDAR applications in support of partner airline implementation.

The WMO Secretariat would like to express thanks to consultant, Mr Frank Tamis, who was responsible for the initial draft versions of the specification under the direction of the former WMO AMDAR Panel, the CBS Expert Team on Aircraft-based Observing Systems and the CIMO Task Team on Aircraft-based Observations.

Dean Lockett, WMO Secretariat

U.S. WVSS-II Program Grows Support to WMO Region IV

The United States National Weather Service (NWS) continues the installation of the Water Vapor Sensing System (WVSS-II), in conjunction with the U.S. AMDAR component, the Meteorological Data Collection and Reporting System (MDCRS).  To date there are 112 aircraft equipped with WVSS-II in the U.S. network.  This includes 25 B757-200 aircraft from UPS, 31 B737-300 aircraft from Southwest Airlines, and 56 B737-700 aircraft also from Southwest Airlines.  Figure 1 shows a typical 24 hour period of WVSS-II data with well over 55,000 moisture observations reported during that time.  The network currently provides over 1,000 soundings per day in support of NWS operations for services to the public.

In addition to the routes inside the U.S., WVSS-II equipped aircraft routinely fly to destinations throughout WMO Region IV including Canada, Central America and the Caribbean.  Regularly scheduled flights to Guatemala, Honduras, El Salvador, Nicaragua, Costa Rica, Panama, Dominican Republic, and Puerto Rico all contribute to successful forecast operations for the NWS and others in Region IV.  These regional observations support U.S. forecasting operations such as hurricane forecasting and aviation meteorological services.

Figure 1. 24 Hours of WVSS-II Observations from October 16, 2013.

Additionally, these data are available to all NMHSs in the region to support local meteorologists, as well as providing support to interests coming into the area from other regions of the world.

At the recent meeting of the CBS ET-ABO in Geneva, representatives were present from ARINC, Southwest Airlines, and SpectraSensors.  Information was provided on the implementations of MDCRS and WVSS-II, questions from the Expert Team were answered, and support to the current Work Plan was provided as requested by the ET-ABO.


Mode-S EHS Derived Wind and Temperature Observations

A new and developing method to measure upper air wind and temperature from an aircraft platform is being enabled through a process of tracking and ranging by an Enhanced  surveillance (EHS) Air Traffic Control (ATC) radar. The EHS radar interrogates in selective mode (Mode-S) all aircraft in sight, upon which the aircraft replies with a message containing a variety of data, including for example, magnetic heading, airspeed and Mach number. From this information wind and temperature can be inferred.
The Royal Netherlands Meteorological Institute (KNMI) started research on utilizing Mode-S EHS data on request of Air Traffic Control The Netherlands (LVNL) in 2008. The objective was to develop and implement a system to provide nowcast and forecast of wind, temperature and air-density data in a 4D grid covering an area with a radius of about 250 NM around Schiphol, from sea-level to FL450.

Research has shown that the derived wind information, after corrections and quality control, is of similar quality as that of AMDAR, while the temperature information below 300hPa is of clearly lesser quality. The advantage of Mode-S EHS derived observations is that information from all available aircraft - so not only aircraft equipped with AMDAR software - is received, resulting in derived wind and temperature observations of a high spatial and temporal resolution for little cost.

Figure - Current coverage of Mode-S EHS derived and quality controlled Wind and Temperature observations available at KNMI. The example shows 15 minutes of observations for 9th of August 2012 between 10:00 and 10:15 UTC over Western Europe, source MUAC in ASTERIX Cat 48 format, processed by KNMI.

Currently EHS designated airspace is notified by the Civil Aviation Authorities of Germany, United Kingdom, France, Belgium and The Netherlands. The current geographical coverage of the observations as processed by KNMI is shown in the figure above. KNMI has requested NATS (UK) on the conditions under which the Mode-S EHS data ( 11 radars) can be received. Data of France is likely to become available in 2014 and 2015. The area can be further enlarged over the European area when more data becomes available and more States are implementing Mode-S EHS. 

This research was partial funded by The Knowledge Development Center Mainport Schiphol (KDC). The authors wishes to express their gratitude for support, resources and Mode-S EHS data provided by Air Traffic Control The Netherlands (LVNL), KLM (Royal Dutch Airline), the  Boeing Company and the Maastricht Upper Area Control Centre (MUAC) of EUROCONTROL.

For more information please visit the KNMI Mode-S EHS website.

Siebren de Haan and Jan Sondij,  Royal Netherlands Meteorological Institute (KNMI)

A Method to Improve Icing AIRMETS and SIGMETS with AMDAR WVSS-II data

One of the major challenges of aviation meteorology is the forecast of icing. While there has been a significant improvement in numerical weather prediction models, AIRMETS and SIGMETS for icing often cover very large aerial extents and time periods. A forecast for 1200UTC October 22, 2013 over the continental United States (Figure 1) shows AIRMETS for icing cover much of the busy corridor from Atlanta to Upstate New York to just outside Boston, as well as a good part of the Midwest and Great Lakes states.

Figure 1

Experience has found that the AIRMETS and SIGMETS for icing and other phenomena are usually larger than they need to be to account for forecast uncertainty, and they are often difficult to amend due to the lack of PIREPS. It is suggested that AMDAR data from WVSS-II equipped aircraft could be used in real time to verify the presence or absence of a favorable icing environment in order to expand, reduce, or discontinue AIRMETS and SIGMETS issued for icing.

Figure 2

The map in Figure 2 above shows the location of WVSS-II equipped aircraft over the continental United States for the period between 1100 and 1400 UTC, on which is roughly the valid time of the AIRMETS in the previous figure. 

The polygon in Figure 3 is an AIRMET for moderate icing between 10,000’ and 16,000’. 

Note there are soundings in the center at Nashville, TN and several outside of the AIRMET at Memphis, Birmingham, and Little Rock. 

Figure 3

In Figure 4, a sounding from Nashville at the center of the AIRMET 
shows that there are layers conducive to supercooled water vapor between roughly 9,000’ and 18,000’, supporting the icing AIRMET for moderate icing between 10,000’ and 16,000’.

Figure 4

A sounding west of the AIRMET from Little Rock, AR (Figure 5) shows the atmosphere is dry at all levels, suggesting the AIRMET was correctly placed east of this location. 

Figure 5

The current wealth of WVSS-II aircraft over the United States could allow the National Weather Service’s Aviation Weather Center to import WVSS-II AMDAR data into the forecaster workstations to show meteorologists where there are favorable or unfavorable icing environments in relation to their current AIRMETS and SIGMETS for icing. It is possible that an automated process could be constructed to compare WVSS-II data to current AIRMETS and SIGMETS and send alerts to the forecasters to consider amendments to current products.  

Other national meteorological agencies and airlines should consider the addition of water vapor sensors to AMDAR aircraft in order to provide the data that is essential for proper forecast and maintenance of icing advisories, and the overall value of water vapor data to numerical weather prediction models and forecasters in field offices.  

Richard Mamrosh, National Weather Service, USA

WMO AMDAR Observing System Contacts

WMO CBS Expert Team on Aircraft-based Observing Systems Contacts


Mr Frank Grooters (The Netherlands)
Tel : +31 30 229 3250 
Email: fgrooters@gmail.com

Mr Gilles Fournier (Canada)
Tel: +1-819-205-6455
Email: gilles.fournier@ec.gc.ca
WMO AMDAR Observing System Newsletter Editor

Mr Carl Weiss (USA)
Tel: +1-301-7131726-149
Email: carl.weiss@noaa.gov

WMO Scientific Officer, Aircraft-based Observations

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