Investigating SeaWinds Terrestrial Backscatter: Equatorial Savannas of South America

Abstract

Because tropical grasslands play an important role in the storage of global carbon, monitoring them is critical to evaluating global climate change. The goal of this research is to model seasonal SeaWinds Ku-band backscatter in five savanna areas of Colombia, Venezuela, and Brazil as a function of biophysical changes in the savanna landscape. Multiple regression modeling demonstrates that savanna Ku-band backscatter is a function of (1) savanna grass biomass/leaf area, (2) soil moisture, and (3) other soil characteristics. Fit for the regression models is excellent (R = 0.87 and 0.81, respectively, for the horizontal and vertical polarization case). The horizontal - vertical polarization difference is also moderately related to precipitation (R = 0.71). The results from this modeling are consistent with theory predicated on previous C- and X-band research. The possibility of monitoring savanna vegetation, soil moisture, and rainfall using Ku-band radar and scatterometry is discussed.