ENVISAT星载合成孔径雷达反演风场在江苏近海风场研究中的应用初探  

Implement of ENVISAT-ASAR Observed Data in the Wind Fields Investigation of the Offshore Area in Jiangsu Province

作　　者：陈燕 许遐祯 黄敬峰[2] 郭乔影[2] 

机构地区：[1]江苏省气候中心,南京210009 [2]浙江大学农业遥感与信息技术应用研究所,杭州310058

出　　处：《高原气象》2017年第3期852-864,共13页Plateau Meteorology

基　　金：江苏省自然科学基金项目(BK2012493);国家自然科学基金项目(41305013);公益性行业(气象)科研专项(GYHY201306050)

摘　　要：为了弥补海上风的常规直接观测资料较少的不足,探索将合成孔径雷达(Advanced Synthetic Aperture Radar,ASAR)观测资料用于风场研究,以江苏近海为研究对象,利用沿海地面观测数据和2008年11幅ASAR影像反演获得的风速和风向进行对比,并将卫星反演风场同化至数值模式,分析对海上风场模拟效果的改进。结果表明:ASAR影像反演的海面风场和地面实测吻合度较高,可以作为没有直接风观测的海上区域的补充。风速反演值略大于观测值,均方根误差为1.8 m·s^(-1),83.6%的站点偏差在±2 m·s^(-1)之内;风向反演值比观测值偏北,均方根误差为39.3°,41.8%的站点偏差在±22.5°之内。将反演风场同化至WRF模式后,提高了海上风场的模拟效果,风速均方根误差1月降低至0.9 m·s^(-1),7月降低至1.6 m·s^(-1);风向均方根误差1月降低为57.3°,7月降低为50.6°。When the study the characteristics of offshore wind farms,less direct observations at sea is an important constraint. Satellite observation is high resolution and all-weather observation; It is an important method to overcome the lack of in-situ observations of wind fields over sea surface. This paper focus on the offshore area of Jiangsu Province and take advantage of the ASAR（Advanced Synthetic Aperture Radar） observations in ocean wind field＇s investigations. The ocean winds retrieval form 11 ASAR observed data in year 2008 are firstly evaluated with observations from 21 meteorological stations in coastal/offshore area,then the ocean winds retrieval form ASAR data are assimilated into the WRF（Weather Research and Forecasting model） for the numerical simulations.The results show that： The ocean winds retrieval form ASAR observed data agree well with the meteorological station observations. The wind speeds retrieval form ASAR data are slightly greater than station observations with an absolute error of 0. 5 m·s^（-1）,a relative error of 15. 3% and a root mean square error（RMSE） of1. 8 m·s^（-1）; 83. 6% of the wind speeds retrieval form ASAR data are of a bias of ±2 m·s^（-1）. The wind speeds retrieval form ASAR data overestimate while meteorological station observed wind speed less than 6. 0 m·s^（-1）.The inversed wind directions have a north shift with a mean bias of-10. 6° and a RMSE of 39. 3°; 83. 6% of the wind directions retrieval form ASAR data are of a bias of ±22. 5°. The ASAR observations are proved to be a good data source for sea surface wind field analysis. With the ocean winds retrieval form ASAR observed data assimilated,the RMSE of WRF model simulations in wind speed decreases from 1. 4 m·s^（-1） to 0. 9 m·s^（-1） in the January case,and from 2. 9 m·s^（-1） to 1. 6 m·s^（-1） to the July case,the simulated errors at 80% observation stations are less than 2. 0 m·s^（-1）. The simulated RMSE in wind direction decreases from 73. 1° to 57. 3° in

关 键 词：同化模拟 合成孔径雷达 风场检验 江苏近海风场 

分 类 号：P425.63[天文地球—大气科学及气象学]