Normalized Residual Scattering Index Applied to Aquarius L-Band Measurements

A normalized residual scattering index is introduced. This index is based on the relationship between coincident microwave-backscatter and brightness-temperature observations. In this letter, the L-band NRSI is shown to correlate with vegetation cover conditions on a global scale. The interpretation of global observations from the Aquarius satellite is based on Passive Active L-band System airborne data collected during field experiments together with ground truth. The benefit of the method is that it is sensitive to land-cover features affecting both active and passive measurements while being insensitive to surface effects such as soil moisture.