Although we did not consider the soil moisture information as a significant component of the current analysis, for the soybean study, the RVI did not correlate well with observed soil moisture (r = 0.41 and 0.34 for the L- and C-bands, respectively). Since there was no tillage during the study, the surface roughness did not change significantly during the experiment. The objective of this study was to examine a proposed vegetation parameterization scheme using radar observations that could be used to estimate vegetation water content as part of the SMAP mission. VWC is a critical variable in the estimation of soil moisture from passive microwave observations. Currently, visible and infrared sensors are used to estimate
VWC; however, these are not available on the same satellite platform, and they have known limitations. Development of this radar-based parameterization using data available from SMAP may be more robust and accurate.