ASCAT与HY-2A风场产品在南海的精度评估

EVALUATION OF ASCAT AND HY-2A SATELLITE SCATTEROMETER WINDS VECTORS IN THE SOUTH CHINA SEA

基于中国科学院南海海洋研究所提供的2012年1月1日—2013年12月31日西沙自动气象站观测资料以及同时间序列的欧洲中心ERA-interim再分析风场产品,统计了ASCAT和HY-2A散射计风场产品的误差特征,分析散射计资料在南海的适用性。分析得出:ASCAT和HY-2A的风速、风向与自动站一致性高,相关系数均大于0.85,ASCAT风速和风向均方根误差分别为1.57 m/s和15.42°,HY-2A均方根误差略微偏大,分别为2.02 m/s和24.75°;ASCAT和HY-2A散射计与ERA-interim风速、风向有很好的一致性,在不考虑低风速(<3 m/s)的条件下,风速均方根误差分别为1.40 m/s和1.56 m/s,风向均方根误差分别为15.09°和17.07°,与设计精度一致,表明ASCAT与HY-2A风场产品在南海是适用的。此外,散射计相对再分析风场的偏差没有明显的季节性变化。

The study presents a quality assessment of ASCAT and HY-2A scatterometer sea surface wind data based on comparison with automatic weather stations （AWS） data from Xisha observation station, which was established by the Institute of South China Sea Oceanography, Chinese Academy of Science, and numerical model data from European Center for Medium Range Weather Forecasts （ECMWF） during January 1, 2012-December 31, 2013, to verify the applicability of two scatterometer in the South China Sea. The results show that the scatterometer data have a good consistency and large correlation with the AWS, with the correlation coefficient being greater than 0.85. The root-mean-squared error （RMSE） of wind speed and direction is 1.57 m/s and 15.42 ° for ASCAT, and 2.02m/s and 24.75 ° for HY-2A, respectively. The scatterometer data also have a good consistency with ERA-interim. Ignoring the low wind （〈3 m/s）, the RMSE of wind speed between scatterometer and model is 1.40m/s for ASCAT, and 1.56m/s for HY-2A, and the RMSE of wind direction is both smaller than 20 °, 15.09 ° and 17.07 ° respectively, which can satisfy the design requirements for a scatterometer. These evaluation results indicate that the wind data from ASCAT and HY-2A is applicative in the South China Sea. Besides, and no clear seasonal variation exists for the residuals between the scatterometer and the ERA-interim.