QuikSCAT卫星遥感风场可靠性分析及其揭示的中国近海风速分布

利用2000—2009年美国国家航空航天局(NASA)在中国近海海域(0°~45°N,105°~135°E)的QuikSCAT卫星遥感风场资料与近海测风塔(位于上海近海)、海上石油平台(位于东海和渤海)、岛屿站(南海珊瑚岛和西沙海边观测塔)的实测风场资料进行对比分析,检验了QuikSCAT卫星遥感风场资料在中国近海海域的可靠性。研究结果如下:各站点实测风速与站点位置以及站点附近的QuikSCAT卫星遥感风场资料相关系数均在0.7以上;QuikSCAT卫星遥感风场资料与海上石油平台的风速均方根误差较小(约1.5 m/s);其年均值均大于实测值,差值范围是0.1~1.3 m/s;其Weibull形状参数K与海上石油平台以及近海测风塔的K值较为接近,表明QuikSCAT卫星遥感风场资料各风速段的频次分布形态与观测站的实测值基本吻合,QuikSCAT卫星遥感风场资料能基本合理地反映出中国近海风速的分布状况。利用QuikSCAT卫星遥感风场资料分析了中国近海及其邻近水域风速的空间分布特征:(1)台湾海峡是中国近海风速最大的区域,从台湾海峡向东北至日本海,往西南至南海北部115°E附近和巴林塘海峡为风速的次大值区;(2)28°N到长江入海口的东海海域年均风速为7.0~7.5 m/s,在黄海和渤海为5.5~7.0 m/s,在南海北部自东向西由8.5 m/s递减为6.0 m/s,北部湾最大风速区位于东方附近海域。

The validation analysis of QuikSCAT wind speed and the wind distribution in China’s offshore areas

QuikSCAT satellite remote sensing wind data over China's offshore areas(0°—45°N, 105°—135°E) are compared with in-situ wind measurement data from platforms located in the East China Sea and Bohai Sea, offshore wind mast in Shanghai and the island stations at Shanhu Island and Xisha Island. It is found that the correlation coefficients of in-situ wind speed and QuikSCAT wind speed nearby in-situ sites are greater than 0.7. The root mean square error of QuikSCAT wind speed at these sites is about 1.5 m/s. The error is relatively large for offshore wind mast and island stations. QuikSCAT mean wind speed is higher than the measured values and the difference is in the range of 0.1—1.3 m/s. The difference of Weibull shape parameter K of QuikSCAT wind is smaller at offshore oil platforms and offshore wind mast (the absolute value: 0.04—0.43). It is clear that the wind speed distribution of QuikSCAT and the measurements are consistent. Overall, QuikSCAT wind data reasonably reflect the wind speed distribution in China's offshore areas. With the QuikSCAT wind speed data from 2000 and 2009, we calculate the annual and seasonal mean wind speed in China's offshore areas and adjacent area. The results are as follows: (1) The largest offshore wind speed is in Taiwan Strait and in the area from Taiwan Strait to Japan Sea and the area near 115°E to Bahrain Tong Strait(8.0—8.5 m/s) is the second highest wind speed area. (2) From 28°N of East China Sea to the Yangtze River, the annual wind speed is 7.0—7.5 m/s, and the wind at Yellow Sea and Bohai Sea is about 5.5—7.0 m/s. It is interesting to find that the wind speed decreases from east to west in the northern South China Sea from 8.5 m/s to 6.0 m/s, and the highest wind area in Beibu Gulf is located in offshore area near Dongfang City.