Cooperative Institute for Research in Environmental Sciences

Science Rendezvous > 2009 Posters
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High Resolution Radiometric Soil Moisture Imaging during CLASIC 2007

Albin J. Gasiewski¹, Eric M. McIntyre¹, Damian Manda¹, and Marian Klein²

¹ Department of Electrical and Computer Engineering, Center for Environmental Technology, University of Colorado at Boulder, Boulder, CO, 80302, USA
² Boulder Environmental Science and Technology, Boulder, CO, 80305, USA

Variations in soil moisture have a significant impact on the radiation balance of the surface and moisture and energy fluxes in the boundary layer. During summer 2007 the CU Center for Environmental Technology operated the PSR/CXI scanning microwave radiometer onboard the NASA P-3B aircraft. The observation domain included a large region of central Oklahoma, and three areas over Texas. During the experiment an unusual amount of precipitation was observed over the domain, which resulted in significant flooding of populated areas. The PSR/CXI instrument was used to obtain high resolution microwave thermal emission maps at C- and X-band over these areas. These maps were used to estimate soil moisture. Data from sources including the Oklahoma Mesonet (air and soil temperatures), National Weather Service (air temperatures), and the SeaWiFS sensor onboard the SeaStar satellite (NDVI) were used in the retrieval algorithm to produce calibrated soil moisture maps representative of the top 5-10 cm of soil. The algorithms developed for this data processing were based on the work of Jackson, et al. between 1999 and 2002. As a result of near-operational processing the products were also used by emergency management personnel responding to severe flooding. We discuss the electromagnetic theory and method of the operational soil moisture retrieval algorithm and the techniques used to acquire the brightness data and utilize the necessary data elements from a variety of sources to compensate for confounding variables. We compare and validate the results of the soil moisture retrieval algorithm to accumulated precipitation as reported by the NWS Nexrad radar system and in situ soil moisture measurements obtained from the Oklahoma Mesonet. Implications for future studies of convection using intensive field sampling efforts include the possibility of sub-diurnal meso-? scale sampling of surface heat flux due to soil evaporation and transpiration.