Soil moisture retrieval over the southern Great Plains: comparisons between experimental remote sensing data and operational products

The southern Great Plains region of the US has been a focus area for experimental remote sensing of surface soil moisture since the 1970´s. Intercomparison of soil moisture retrieval using both experimental data and operational data is carried out during the SGP99 remote sensing campaign in July 1999. Passive microwave measurements obtained from the airborne ESTAR instruments at L-band and TRMM microwave imager (TMI) measurements at X-band were processed to retrieve surface soil moisture during SGP99 and compared to field measurements. TMI retrieved soil moisture for June-September 1999 were compared with operational soil moisture sensors in the Oklahoma (OK) Mesonet system. To mimic operational products, the correction for vegetation and surface roughness in the TMI retrievals are based on average literature values, and surface temperatures estimated from a land surface hydrologic model forced with operational products.