Ground-based microwave radiometer measurements during the Southern Great Plains '97 experiment

An EOS interdisciplinary science hydrology experiment conducted by NASA and USDA called Southern Great Plains '97 (SGP97) took place from June 18 to July 16, 1997 in Oklahoma, with a goal of mapping surface soil moisture with an airborne L-band microwave radiometer on a daily basis for a month over an 11000 km2 area at 800 m resolution. Operated at a scale equivalent to a GCIP ISA, this experiment offers a unique data set for examining the applicability of microwave soil moisture retrieval algorithms at spatial and temporal scales more typical of satellite systems, as well as the value of soil moisture information to regional scale hydrology, weather, and land-atmosphere interactions. The spatial area covered ranged from the Little Washita River watershed in the south to the Department of Energy's ARM/CART Central Facility near the Kansas border in the north. Extensive ground measurements of soil moisture were collected at the Little Washita watershed and the Central Facility area as well as USDA's El Reno watershed west of Oklahoma City in conjunction with the aircraft mapping. A total of 18 complete missions and 3 partial missions were successfully flown with the ESTAR airborne L-band 1.4 GHz microwave radiometer during the experimental period. Besides the core mapping by ESTAR, the experiment included a comprehensive flux measurement component, enhanced ground measurement of soil and vegetation properties, extensive soil moisture sampling through both gravimetric and TDR techniques, other aircraft remote sensing instruments and access to automated micrometeorological and soil profile measurements from the three research instrument networks in the SGP97 area.