On accuracy of SAR wind speed retrieval in coastal area

Abstract

In coastal region, the overestimation of wind speed are observed in SAR wind speed retrievals and the contamination from land and ships are considered as one of the main reasons. A novel method for calculating the value of normalized radar cross section (NRCS) cell has been developed to improve high-resolution synthetic aperture radar (SAR) wind retrieval in the case of contamination. The ratio of median and mean (Rmmpp) has been proposed to assess the effect of the distribution of NRCS on wind retrievals quantitatively. In this research, Sentinel-1 interferometric wide-swath (IW) dual polarization SAR data were collocated with in situ wind measurements from National Data Buoy Center (NDBC) for comparison. CMOD5, CMOD7 and the C-band Cross-Polarization Ocean (C-2PO) were used for wind retrievals. The statistic validation results show that the proposed method is more robust than the conventional method for wind speed retrievals. In addition, the Rmmpp could be used as an indicator for the reliability of SAR wind and the accuracy of wind speed increase with the Rmmpp increasing from 0.2 to 1.0 in the coastal area.