This programme, using predominantly existing on-board sensors and systems, now produces nearly half a million observations per day of temperature, winds and, increasingly, humidity in support of the WMO Global Observing System (GOS).
There are three elements of the AMDAR observing system that make it especially valuable:
- AMDAR wind and temperature data have been shown to be similar in quality (i.e. accuracy or uncertainty of measurement) to that of radiosondes;
- The measurement sensors and systems on the aircraft are able to produce these data at a very high rate or frequency of measurement, thus providing very fine detail within the vertical profiles; and
- Owing to the frequency with 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.
Forecast meteorologists find AMDAR data valuable and useful, providing 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;
- Jet stream location and intensity;
- Precipitation amounts and rates; and
- Conditions leading to aircraft icing.
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. Quantitatively, AMDAR and other aircraft-based observations provide an improvement in forecasting ability through a reduction in NWP forecast error of up to 15-20%.
Pilots and airline flight and dispatch managers know the impacts atmospheric phenomena have on airline operations, efficiency and safety – each of which are critical to the financial bottom line of the airline. “Weather accounts for 70% of all air traffic delays within the U.S. National Airspace System,” concluded the 2007 Report of the Weather-ATM Integration Working Group of the United States Research, Engineering and Development Advisory Committee. It further noted, “that as much as two-thirds of the weather related delay are potentially avoidable.“ The US Congressional Joint Economic Committee report Your Flight Has Been Delayed Again (May 2008) further found that:
- The total cost of domestic air traffic delays to the economy was as much as US$ 41 billion for 2007;
- Air-traffic delays raised airlines’ operating costs by US$ 19 billion;
- Delays cost passengers time worth up to US$ 12 billion; and
- Indirect costs of delay to other industries added roughly US$ 10 billion to the total burden
The financial interests of airlines are, therefore, well served by their contributing to any efforts to improve weather forecasting ability. Such improvements reduce their costs and those to the community. Airlines participating in the AMDAR programme also contribute to the efficiency and safety of the aviation industry and their own operations.
For more information on the AMDAR programme and requirements for participation in it, see the WMO AMDAR website.