High Spatial Resolution Soil Moisture with Passive Active Sensors Using a Change Detection Approach: Studies Using SMAPVEX12 Data

Wednesday, 17 December 2014: 9:00 AM
Bin Fang, University of South Carolina Columbia, Columbia, SC, United States, Venkataraman Lakshmi, Univ South Carolina, Columbia, SC, United States, Rajat Bindlish, U. S. Dept. of Agriculture, Beltsville, MD, United States and Thomas J Jackson, USDA ARS, Pendleton, OR, United States
Soil moisture is an important variable in many areas of geosciences. The passive microwave sensors have been providing soil moisture of various spatial resolutions and are available for all-weather conditions. However, restricted by the antenna diameter of microwave radiometer, the spatial resolution of passive microwave soil moisture product is at tens of kilometers and needs to be improved for many applications. The SMAP (Soil Moisture Active Passive) is set to be launched in late 2014 and will be the first mission to provide L-band radar/radiometer soil moisture retrievals at three resolutions. The SMAPVEX12 is a pre-launch field validation experiment for evaluating and testing the soil moisture retrievals acquired from SMAP satellite. Airborne data using PALS (Passive/Active L-band Sensor) at two along-track resolutions (650 m and 1590 m) and UAVSAR (Uninhabited Aerial Vehicle Synthetic Aperture Radar) at 5 m spatial resolution as well as in-situ measurements were collected during the campaign. The study will implement a Single Channel Algorithm (SCA) to retrieve soil moisture from high/low altitude PALS L-band radiometer observations, as well as produce downscaled soil moisture change by combining low spatial resolution soil moisture retrievals and high spatial resolution PALS L-band radar observations through a change-detection algorithm, which models the relationship between change in radar backscatter and the change in soil moisture.