Sea surface wind field was retrieved from high-resolution SIR-C SAR data by using CMOD algorithms off the east coast of Korea. In order to extract wind direction information from SAR data, a two-dimensional spectral analysis method was applied to the normalized radar cross section of the image. An 180˚-ambiguity problem in the determination of wind direction was solved by selecting a direction nearest to the wind vector of the ECMWF reanalysis data. Comparison of the wind retrieval patterns with the ECMWF and NCEP/NCAR dataset showed RMS errors in the range of 1.30 to 1.72 ms-1. In contrast, comparison of wind directions revealed large errors of greater than 60˚, which is enormously higher than the permitted limit of about 20˚ for satellite scatterometer winds. Compared with wind speed results from different algorithms, wind vectors based on commonly-used CMOD4 algorithm showed good agreement with those derived by other algorithms such as CMODIFR2 and CMOD5, particularly at medium winds from 4 to 8 ms-1. However, apparent discrepancy appeared at low winds (〈 4 ms-1). This study also addressed an importance of accurate wind direction data to improve the accuracy of wind speed retrieval and discussed potential causes of wind retrieval errors from SAR data.

• Kim, Tai-Sung(Department of Science Education, Seoul National University)
• Park, Kyung-Ae(Department of Earth Science Education/Research Institute of Oceanography, Seoul National University) | Park, Kyung-Ae
• Moon, Woo-Il(Research Institute of Oceanography/Department of Geophysics, University of Manitoba) | Moon, Woo-Il