Airborne Millimeter Wave Radiometer for 94/183 GHz High Altitude Atmospheric Measurements

A moisture sounding imaging radiometer operating at 94/183 GHz has been developed for NASA/GSFC to perform high altitude measurements onboard a WB-57F aircraft [1,2]. The instrument known as the Advanced Microwave Moisture Sounder (AMMS) was used to perform measurements near the 183.3 GHz water vapor line with three data channels and simultaneously collected data at a single window channel at 94 GHz to measure surface emissivity variations over land. The instrument operated under microcomputer control throughout each flight and collected data continuously from aircraft takeoff to landing. The radiometer was integrated into the WB-57F instrumented pallet for a series of data flights between June 1979 and June 1981. A portable ground support system was used following each flight to provide quick-look analysis of the data. The Cooperative Convective Precipitation Experiment (CCOPE) was conducted in the Miles City, Montana area from May through August 1981. CCOPE's main objectives were to study the life cycles of summer convective clouds and storms and to learn how natural processes interact to produce storms. A typical WB-57F data flight during CCOPE involved the aircraft flying above a storm at 18 km altitude within a 150 km radius circle near Miles City. At the same time other aircraft would fly in and around the storm. Other equipment in operation at the same time included ground based weather radar, weather balloons, and a satellite-linked network of 125 ground stations.