Surface Heterogeneity Issues in Remote Sensing of Soil Moisture

In advance of two upcoming soil moisture satellite missions, it is important to improve our understanding of the error sources associated with satellite-based soil moisture retrievals. Uncertainties in remotely-sensed soil moisture estimates can be attributed to many factors, including errors in measured brightness temperatures and input parameters, deficiencies of the radiative transfer scheme and variability of surface conditions within a satellite footprint. The purpose of this study is to quantify the magnitude of scaling errors attributable to heterogeneity within a satellite footprint of soil and vegetation properties and to present a method to reduce these errors. We address this problem using simulated single-frequency, single-polarization passive L-band microwave observations for an agricultural region of the United States.