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Aircraft Weather Data

Aircraft Weather Data. History, Data Quality, Utility and Display. Aircraft Weather Data – Outline. A short history of aircraft weather data Different sources of data from aircraft Water vapor measurements Resolution and accuracy Data utility

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Aircraft Weather Data

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  1. Aircraft Weather Data History, Data Quality, Utility and Display

  2. Aircraft Weather Data – Outline • A short history of aircraft weather data • Different sources of data from aircraft • Water vapor measurements • Resolution and accuracy • Data utility • Advantages and disadvantages versus other upper air data • Display of data • Future plans

  3. Aircraft Weather Data – A Short History • Aircraft have been used as a source of weather data since the dawn of aviation. • In 1904, the United States government began using aircraft to conduct atmospheric research. Weather instruments on a Navy biplane

  4. Aircraft Weather Data – A Short History • In 1931, the Weather Bureau began regular aircraft observations at Chicago, Cleveland, Dallas and Omaha, at altitudes reaching 16,000 feet. • This program replaced weather observations from "kite stations."

  5. Aircraft Weather Data – A Short History • In 1937, the first official Weather Bureau radiosonde sounding was made at Boston, Mass. • Weather soundings from aircraft soon ended.

  6. Aircraft Weather Data – A Short History • The invention of aircraft data links in the 1970s created renewed interest in using aircraft as weather platforms. • The first automated aircraft weather reports were made in 1979. ACARS display units in aircraft cockpit

  7. Aircraft Weather Data – A Short History • In the 1980's, the Earth Systems Research Laboratory received permission to use aircraft reports in experimental NWP models. • In 1993 ESRL began regular assessment of aircraft data quality. A web based display was developed. Earth Systems Research Lab

  8. Aircraft Weather Data – A Short History • March 20, 1996 the airlines agreed to allow direct access to their data by NWS WFO meteorologists. • Other users now include the FAA, DOD, and universities. NWS office in Green Bay, Wisconsin

  9. Aircraft Weather Data – Different Sources • You may have heard aircraft data referred to as ACARS, MDCRS, AMDAR or TAMDAR. • ACARS (Aircraft Communications, Addressing, and Reporting System) is the name of a datalink service provided by Aeronautical Radio Inc. that sends information between aircraft and ground stations. • MDCRS (Meteorological Data, Collection and Reporting System) is the weather portion of the ACARS data stream. • Aircraft Meteorological DAta Report (AMDAR) is the preferred term by the WMO and NWS. • TAMDAR (Tropospheric AMDAR) is provided by a private company, AIRDAT, using a regional air carrier.

  10. Aircraft Weather Data – Different Sources • Eight U.S. Airlines share AMDAR • American • Delta • FEDEX • Mesaba • Northwest • Southwest • United • UPS The airlines share the cost of down linking the data with the NWS and FAA

  11. Aircraft Weather Data – Different Sources • 14 Countries now share AMDAR from 2,300 aircraft • Australia, New Zealand, China, • Hong Kong China, Saudi Arabia, • South Africa, United States, Canada, • Netherlands, United Kingdom, France, • Sweden, Hungary, Germany • 5 Countries developing AMDAR systems • Chile, Finland, Argentina, • Republic of Korea, and • United Arab Emirates

  12. Aircraft Weather Data – Different Sources • The number of observations has increased greatly, and is now over a quarter million per day from around the world!

  13. Aircraft Weather Data – Measured Quantities • Nearly all participating AMDAR aircraft report temperature and wind data. • Temperature is determined by the Total Air Temperature sensor, while ground relative winds are computed using an Inertial Navigation System or GPS. • As of 2006, fewer than 10 percent of AMDAR aircraft measured water vapor, turbulence and icing.

  14. Aircraft Weather Data – Water Vapor • Measuring water vapor in the upper atmosphere is a difficult task for any sensor. • NWS radiosondes use thin film capacitors to measure relative humidity. • The sensors are relatively inexpensive, but sometimes are prone to errors at very high and very low relative humidity.

  15. Aircraft Weather Data – Water Vapor • Studies in the early 1990s showed that relative humidity measurements from commercial aircraft were feasible. • A sensor called the “Water Vapor Sensing System” (WVSS) using a thin film capacitor was installed on six UPS aircraft between 1997 and 1999. Water Vapor Sensing System Unit

  16. Aircraft Weather Data – Water Vapor While the WVSS data compared favorably with radiosondes, the sensors needed to be replaced too frequently to be used on commercial aircraft.

  17. Aircraft Weather Data – Water Vapor • A new sensor (WVSS-II) employs a diode laser to measure water vapor mixing ratio. • WVSS-II was installed on 25 UPS aircraft between 2004 and 2005. WVSS-II laser diode shown next to a penny, for size comparison purposes.

  18. Aircraft Weather Data – Water Vapor Field studies were conducted at the Louisville airport (June 2005, November 2006) to compare WVSS-II with precision radiosondes. A mobile sounding unit from the University of Wisconsin launched radiosondes every three hours during the evening and overnight hours. This was supplemented by interferometer data. WVSS-II and radiosonde data within an hour and 50km of each other were compared. Mixing ratio was measured by WVSS-II and relative humidity by the radiosonde.

  19. Aircraft Weather Data – Water Vapor Results from the WVSS-II and radiosonde comparison showed an average relative humidity bias near zero in the lowest 200hPa and about 5% above. Standard deviations are about 5% below 800hPa and 10% above. The accuracy satisfies WMO requirements for regional forecast applications.

  20. Aircraft Weather Data – Resolution And Accuracy • Much as ASOS, AWOS, DOT and mesonet observations have differences in reporting frequency, accuracy and reliability, so too do reports from aircraft. • Most AMDAR from foreign airlines conform to a WMO reporting standard called ARINC 620. U.S. AMDAR observations generally do not.

  21. Aircraft Weather Data – Resolution And Accuracy • ARINC 620 standard provides a data point every 300 feet up to around 850 hPa, then every 1000 feet to cruise altitude. • Most U.S. AMDAR report data at set 1,000-2,000 foot intervals through ascent and descent. • The NWS and WMO are urging U.S. airlines to adopt ARINC 620 standard.

  22. Aircraft Weather Data – Resolution And Accuracy • Many studies have been conducted to compare AMDAR to radiosondes, profilers and other upper air data. • They generally show that AMDAR temperatures and winds are slightly superior to those from radiosondes.

  23. Aircraft Weather Data – Resolution and Accuracy • A 2001 study by Erik Andersson, Carla Cardinali and Antonio Garcia-Mendez of the ECMWF showed the addition of AMDAR resulted in significant model forecast improvements, all the way out to 7 days.

  24. Aircraft Weather Data – Resolution and Accuracy

  25. Aircraft Weather Data – Resolution and Accuracy • A study conducted by Ralph Petersen, Geoff Manikin and Dennis Keyser showed that AMDAR contributes significantly to the RUC at all run times. • In fact, the RUC provides little value at asynoptic times without AMDAR – the RUC accuracy declined 20% in the days following September 11, 2001 when air traffic was grounded.

  26. Aircraft Weather Data – Forecast Applications • AMDAR data have proven extremely useful in a wide variety of forecast situations, including: • Aviation • Low level wind shear • Ceilings and visibilities • Icing and turbulence • Winter Storms • Precipitation type • Lake effect snow • Thunderstorms • Convective initiation • Calculation of stability indices • Fire Weather • Mixing heights • Haines indices • Relative humidity forecasts • Marine Forecasts • Small craft and Gale Warnings • Hazardous Materials Support • AMDAR can be used to support HAZMAT teams • Can be input into local dispersion models

  27. Advantages and Disadvantages • Like any system, AMDAR has advantages and disadvantages.

  28. Disadvantages • Volume of data may be reduced during large storms. • Most aircraft do not measure water vapor. • AMDAR soundings usually end at 500hPa for regional aircraft, and 250hPa for most others.

  29. Advantages • Soundings are not limited to 00UTC and 12UTC. This is important especially during convective season. • Many airports have 10 or more soundings per day (Some large airports have over 100). • AMDAR does not have limiting angles problems like radiosondes. • Inexpensive (AMDAR sounding less than $1 vs. $200 for radiosonde)

  30. Aircraft Weather Data – Display Options • AMDAR are available in real-time to the NWS, FAA, and DOD via the ESRL aircraft data web at http://amdar.noaa.gov. • AMDAR may also be displayed on AWIPS, via the volume browser.

  31. ESRL Aircraft Data • http://amdar.noaa.gov has links to AMDAR data, FAQs, research papers, training materials and more. • Web site has archive of about 3 years of data, allowing for easy retrieval for case studies. • Data can be found at http://amdar.noaa.gov/java.

  32. AMDAR Display Options– Web • ESRL web page should allow access to data at all NOAA installations. • Contact Bill Moninger at ESRL regarding access issues. (303) 497-6435 William.R.Moninger@noaa.gov • Data may not be redistributed in real time.

  33. Web Display Resources • Additional training on the use of the web page can be found at http://amdar.noaa.gov/videos/.

  34. Future Plans - NWS • Support existing AMDAR data network • Expand number of participating regional airlines • Reduce redundant AMDAR soundings at hubs (optimization) • Increase number of water vapor sensors • Let contract for management of water vapor sensing program this year • Deploy 110 units annually through 2010 • Reach ~1600 units deployed by 2020

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