Validation of Tropospheric Airborne Meteorological Data Reporting (TAMDAR) Temperature, Relative Humidity, and Wind Sensors During the 2003 Atlantic THORPEX Regional Campaign and the Alliance Icing Research Study (AIRS II)

The Tropospheric Airborne Meteorological Data Reporting (TAMDAR) sensor is designed to measure winds, temperature, humidity, turbulence and icing from regional commercial aircraft (Daniels, 2002). AirDat, LLC, developed the sensor under contract for NASA (Daniels, et al., 2004). A system of TAMDAR sensors and datalinks on a sufficient number of aircraft would provide high temporaland spatial-resolution wind and temperature data in the lower troposphere. Such a system has the potential to substantially improve weather forecasting. Moreover, the high-resolution humidity data produced by TAMDAR is unprecedented, and may provide substantial benefits. The meteorological community is keenly interested in additional observations of the lower troposphere and in particular moisture data as evidenced by the American Meteorological Society Statement (AMS Council, 2003). The University of North Dakota (UND) Cessna Citation II and the NASA ER-2 participated from November 19 to December 14, 2003, a period of overlap between two separate field campaigns, the 2003 Atlantic THORPEX Regional Campaign (ATReC) and the Second Alliance Icing Research Study (AIRS II). ATReC flights originated from Bangor, Maine, and were typically over the North Atlantic, while AIRS II flights were over Ottawa, Ontario and the Mirabel Airport outside Montreal, Quebec. To support both campaigns, it was necessary to identify suitable cases for targeting, provide information on the location of sensitive areas, and have the facilities to control each observing system at short notice. TransAtlantic routing of commercial aircraft was a daily consideration. Early morning meteorological reports were used for daily aircraft routing. Additional information can be found on the website (Murray and Nguyen, 2003). As part of the development process, the TAMDAR sensor has been tested in various ground-based facilities and on different atmospheric research aircraft (Daniels, et al., 2004). The subject of this report is validation of TAMDAR sensor using data other instruments installed on the UND Citation. Additional validation data came from GPS dropsondes (from the UND Citation). In addition, other data from two sounding instruments is used for comparison purposes. Among the various instruments installed on the NASA ER-2 aircraft, the NPOESS Atmospheric Sounder Testbed Interferometer (NAST-I), MODIS Airborne Simulator, and the Scanning High-resolution Interferometer Sounder (S-HIS), are of particular interest (Murray, et al., 2003). NAST-I is designed to support the development of future satellite temperature and moisture sounders such as the IASI (Interferometer Atmospheric Sounding Instrument) on the METOP satellite (2005), the CrIS (Cross-track Infrared Sounder) on the NPP (2006) and NPOESS (2008–2010) satellites, and the HES (Hyperspectral Environmental Sensor) on the GOES-R satellite (approximate launch 2013). The Atmospheric Infrared Sounder (AIRS) instrument is an infrared sounder on the AQUA satellite. Among the important parameters derived from AIRS observations are atmospheric temperature and humidity profiles. These parameters (used in this paper) are retrieved with the same methodology as that used with NAST-I data. Sounding data from the AIRS and NAST-I instruments is used for comparison to TAMDAR and UND Citation in-situ data.