Observations From the Global AMDAR Program Presentation to WMO TECO May 2005 by Jeff Stickland Technical Coordinator, WMO AMDAR Panel

System Description Aircraft Meteorological Data RelayAMDAR = AMDAR is: A fully automated upper air observing system; Collects high quality upper air observations of wind speed and direction, temperature, and sometimes turbulence and humidity; From many existing commercial aircraft; In collaboration with national domestic and international airlines; – standard installed high quality sensors for wind, temperature and turbulence plus height (pressure), time and position; Uses existing aircraft and airline infrastructure including: – onboard avionics and communications hardware and software; – Airlines normally use the international communications system called Aircraft Communications and Reporting System (ACARS). Global services are provided by 2 companies – ARINC and SITA.

System Description (cont.) Humidity sensors are being developed and will be added in the future to SOME aircraft; – airline ground-based data processing systems; The only additional requirement to make AMDAR work is special AMDAR software installed in the aircraft avionics or communications hardware; No new hardware is required on the aircraft; TYPICAL AMDAR INSTALLATION = FITTED WITH EXISTING SENSORS + AVIONICS HARDWARE + AVIONICS SOFTWARE + COMMUNICATIONS AMDAR SOFTWARE +

Why is AMDAR Data Needed? ¡ To provide a cost effective source of upper air observations to support national, regional and global basic meteorological operations and research; ¡ AMDAR data can be used in most meteorological applications that use upper air data obtained from conventional observing systems. Vertical profiles of temperature and wind are often the most valuable: ¡ Examples in operational bench forecasting for the short to medium term include- Severe weather forecast and warning services; Public weather forecast and warning services; Aviation weather services (enroute and terminal area forecasts supporting airlines, air traffic control and airport operations; Marine and industrial applications; Environmental monitoring and warning applications; Climate studies, etc. ¡

¡ Operational Cost compared to radiosonde is 1% ¡ To provide data from data sparse areas around the world to improve local forecasts and to contribute to the WMO World Weather Watch Global Observing System ¡ To help provide a more comprehensive assessment of the atmosphere for local modelling research, local forecasting, etc; ¡ For forecast verification; ¡ To meet the NWP community’s requirement for greater quantities and improved coverage of relevant upper air data;

Data Requirements Desirable Horizontal Spatial and Temporal Density: 1 profile on 250 km grid at 3 hourly intervals BASIC Data

Additional Data Data Requirements (cont.)

Mandatory and Optional Reported Elements ElementMandatory/OptionalRequires Additional Onboard Processing Aircraft identifierM Phase of flightM LatitudeM LongitudeM Day & time of observationM Pressure altitudeM Static air temperatureM Wind directionM Wind speedM Maximum windM Roll & pitch angle flagM* HumidityO* TurbulenceO* IcingO*

24 Hour Global Coverage 13 April 2005 Courtesy NOAA FSL

24 Hour AMDAR Profiles 13 April 2005 Courtesy NOAA FSL

E-AMDAR Temperature Quality Frequency distribution of the mean temperature difference (OBS–Background) KNMI QEV Report - April - June 2001

E-AMDAR Wind Speed Quality Frequency distribution of the mean wind speed difference (OBS–Background) KNMI QEV Report - April - June 2001

WVSSII on N407 Versus Sonde at Mexico City, 12:53, 28 March 2005

LIT WVSS-2 vs. Raob Comparison

SDF WVSS-2 Comparisons 31 MAR 05 Comparisons of 4 WVSS-2 aircraft on descent into SDF. Between 06z and 08z the profiles changed markedly as a line of thunderstorms approached and moved through, along with cold front passage. 2 Ascents are also included. Things stabilized by around 10z.