L-band SAR-derived Sea Surface Wind Retrieval off the East Coast of Korea and Error Characteristics

L밴드 인공위성 SAR를 이용한 동해 연안 해상풍 산출 및 오차 특성

  • Kim, Tae-Sung (Department of Science Education, Seoul National University) ;
  • Park, Kyung-Ae (Department of Earth Science Education / Research Institute of Oceanography, Seoul National University) ;
  • Choi, Won-Moon (Department of Science Education, Seoul National University) ;
  • Hong, Sungwook (Satellite Analysis Division, National Meteorological Satellite Center) ;
  • Choi, Byoung-Cheol (Satellite Analysis Division, National Meteorological Satellite Center) ;
  • Shin, Inchul (Satellite Analysis Division, National Meteorological Satellite Center) ;
  • Kim, Kyung-Ryul (School of Earth and Environmental Sciences / Research Institute of Oceanography, Seoul National University)
  • 김태성 (서울대학교 과학교육과) ;
  • 박경애 (서울대학교 지구과학교육과/서울대학교 해양연구소) ;
  • 최원문 (서울대학교 과학교육과) ;
  • 홍성욱 (국가기상위성센터 위성분석과) ;
  • 최병철 (국가기상위성센터 위성분석과) ;
  • 신인철 (국가기상위성센터 위성분석과) ;
  • 김경렬 (서울대학교 지구환경과학부/서울대학교 해양연구소)
  • Received : 2012.09.16
  • Accepted : 2012.10.23
  • Published : 2012.10.31


Sea surface winds in the sea off the east coast of Korea were derived from L-band ALOS (Advanced Land Observing Satellite) PALSAR (Phased Array type L-band Synthetic Aperture Radar) data and their characteristics of errors were analyzed. We could retrieve high-resolution wind vectors off the east coast of Korea including the coastal region, which has been substantially unavailable from satellite scatterometers. Retrieved SAR-wind speeds showed a good agreement with in-situ buoy measurement by showing relatively small an root-mean-square (RMS) error of 0.67 m/s. Comparisons of the wind vectors from SAR and scatterometer presented RMS errors of 2.16 m/s and $19.24^{\circ}$, 3.62 m/s and $28.02^{\circ}$ for L-band GMF (Geophysical Model Function) algorithm 2009 and 2007, respectively, which tended to be somewhat higher than the expected limit of satellite scatterometer winds errors. L-band SAR-derived wind field exhibited the characteristic dependence on wind direction and incidence angle. The previous version (L-band GMF 2007) revealed large errors at small incidence angles of less than $21^{\circ}$. By contrast, the L-band GMF 2009, which improved the effect of incidence angle on the model function by considering a quadratic function instead of a linear relationship, greatly enhanced the quality of wind speed from 6.80 m/s to 1.14 m/s at small incident angles. This study addressed that the causes of wind retrieval errors should be intensively studied for diverse applications of L-band SAR-derived winds, especially in terms of the effects of wind direction and incidence angle, and other potential error sources.


Supported by : 국가기상위성센터


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