Tropical Cyclone Wind Direction Retrieval from C-Band Dual-Polarization Synthetic Aperture Radar

Derivation of sea surface wind directions is an important step of sea surface wind fields retrieval from spaceborne Synthetic Aperture Radar (SAR) data. The local gradient (LG) method is used in this paper to retrieve the wind directions of C-band dual-polarization $(VV+VH)$ synthetic aperture radar (SAR) images under tropical cyclone (TC) sea states. We compare wind directions derived from 10 dual-polarization SAR images with collocated wind directions from buoys, scatterometer, radiometer, and Hurricane Research Division (HRD) Realtime Hurricane Wind Analysis System (H*Wind) products. Results show that the wind direction root-mean-square (RMS) error and bias are 19.85° and 0.07° for $VH$ polarization, and 24.89° and −1.26° for $VV$ polarization, suggesting $VH$ is more suitable to exact tropical cyclone wind directions than $VV$.