Satellite calibration and validation utilizing the Airborne Polarimetric Microwave Imaging Radiometer (APMIR)

The Airborne Polarimetric Microwave Imaging Radiometer (APMIR) was designed and built by the Naval Research Laboratory, Washington, D.C., as a tool for calibration and validation of the Coriolis WindSat and Defense Meteorological Satellite Program SSMIS satellite radiometer sensors. The satellite sensor data aids in short-term weather modeling and general climatic information via measurements of ocean winds, water vapor, soil moisture, rain rates, and ice/snow characteristics. The APMIR sensor was designed to assist in the fulfillment of the airborne portion of the calibration/validation effort. By underflying a satellite, the airborne sensor data is coincident in space and time with the satellite, allowing an accurate comparison of the viewed scene. Extensive testing of the APMIR system included tip curves, pool views, and radiative transfer model comparisons. The encompassing test methods achieve a high degree of confidence in the APMIR system. APMIR underflew the SSMIS satellite during a March/April 2004 field campaign. Based on the high confidence of the APMIR sensor, and the excellent data comparison of the SSMIS satellite, the APMIR instrument demonstrates itself as a precision tool for calibration and validation activities. The results of the underflights during the March/April 2004 field campaign for the SSMIS satellite are presented.