基于海面位势高度和海表温度构建西太平洋三维温度场

A New Reconstruction Method for the 3-D Temperature Field in the Western Pacific Ocean Based on Steric Height and SST

提出了一个基于上一年逐月三维再分析温盐场和第二年月平均卫星观测数据,包括海表温度SST(Sea Surface Temperature),海面高度异常SLA(Sea Level Anomaly),来推算区域海洋三维温度场的方法。选取西太平洋区域作为验证算法有效的海区。该三维水域的水平海域范围设定为:30°N^50°N,140°W^180°W,水平分辨率为1°;深度方向为从海表至-1 000 m,划分为19层。重构的第一步是利用上一年的逐月的温盐场,在该三维空间的每个网格点上建立一个温度和卫星观测的海表温度、海面位势高度的回归方程。根据该回归方程和第二年的卫星观测数据可以得到第二年的该区域的三维温度场。第二步把相同月份的该区域存在的Argo温度廓线同化进重构的温度场来提高重构的精度。重构的2015、2016年的温度场和CMEMS(Copernicus Marine Environment Monitoring Service)提供的再分温度场的相关系数分别达到了0.992 9和0.991 2,均方根误差为0.79和0.89℃;在-200 m以深的区域,均方根差异小于1℃,-200 m以浅的区域,均方根差异在1~2℃。表明该重构方法是合理有效的,所以基于第一年的温盐三维数据和第二年的卫星观测的海表数据可以重构第二年的三维温度场。

A new method has been developed to reconstruct the 3-D monthly-mean temperature field based on the past one year’s 3-D monthly-mean temperature/salinity(T/S)fields,SLA(Sea Level Anomaly)and SST(Sea Surface Temperature),for the area ranging between 30°N^50°N and 140°W^180°W in western Pacific,with grid step of 1°,and depth of 1 000 m which is divided into 19 levels.In the first step of the method,the 3-D monthly-mean temperature fields are extrapolated by applying linear regression equation on every grid point and the satellite-derived surface fields.In the second step,the EOF analysis method is used to complement the missing data caused by the deficiency of satellite surface observations.In the third step,the Argo profiles are assimilated by the reconstructed temperature fields of the second step to further improve its accuracy.The results of our method perform well because the correlation coefficients between the reconstructed temperature fields of 2015,2016 and the CMEMS(Copernicus Marine Environment Monitoring Service)data are as high as 0.992 9 and 0.991 2,and the rms(root mean square)difference between them is 0.79 and 0.89℃.The rms difference is as low as 1℃below the depth deeper than 200 m and about 1~2℃above the depth 200 m.So it is feasible to use this method to build a high qualified 3-D temperature fields for the Western Pacific Ocean based only on previous one year’s 3-D fields and remote-sensing SST and SLA.