PALS radar signatures of soil surfaces and vegetated sites in Oklahoma during SGP´99

The Passive/Active L-/S-band (PALS) microwave instrument has been developed by the Jet Propulsion Laboratory (JPL) to investigate the synergism of radiometer and radar measurements for soil moisture remote sensing. In July 1999, PALS was installed on the NCAR C-130 with six successful flights near the Oklahoma City during the Southern Great Plains 1999 (SGP99) Experiment. The data from these and subsequent ocean flights indicate a calibration stability of better than 0.1 dB for each flight. During the SGP99 experiment, there was a significant rain event between the second and the third flights. The data from before and after the rain event indicate a change of 3 to 4 dB in all radar polarization channels, and a decreasing radar backscatter with the drying of surfaces. The dataset enables us to illustrate the correlation of multi-polarization radar signatures with the soil moisture and vegetation biomass