Ultra-high-resolution near-coastal wind retrieval for quikSCAT

The SeaWinds on QuikSCAT scatterometer measures near surface ocean winds using radar backscatter values and a geophysical model function. QuikSCAT data is limited in coastal regions due to land contamination of the backscatter measurements. However, wind retrieval in near coastal areas can be successfully accomplished by estimating the amount of land contamination in the backscatter measurements and eliminating measurements which exceed a specified threshold. In order to accurately assess the amount of land contamination in a given measurement, a detailed knowledge of the antenna spatial response is required. The land contribution ratio is used as the contamination metric and is calculated using the spatial response of each QuikSCAT measurement. The land contamination threshold changes during wind retrieval as a function of wind conditions in the local area which allows retrieval closer to the coast as wind speeds increase. To ameliorate processing time the QuikSCAT spatial response is calculated and tabulated prior to wind retrieval. Subjective comparisons to estimated coastal winds show that determining a land contamination threshold using the percent land contribution metric provides accurate wind retrieval up to 25km closer to the coast than. current methods. As a result wind speeds can be accurately retrieved as close as 2.5km from the coast.