南海TOPEX海面高度资料的混合同化试验

ASSIMILATION EXPERIMENT OF BLENDING TOPEX ALTIMETER DATA IN THE SOUTH CHINA SEA

应用普林斯顿海洋模式(POM)，对冬季南海由TOPEX/Poseidon得到的卫星遥感海面高度资料进行混合(blending)同化试验。混合同化的权重系数由以下两者决定：南海POM模式对冬季风强迫产生响应的海面高度场之标准方差；对应期间TOPEX海面高度资料的标准方差。同化结果表明，混合同化方法不失为一种简单而又有效的同化方案。同化得到的南海环流结构与未同化的模式响应场比较可以发现：海面高度资料的同化试验能够有效地修正南海环流的若干大尺度特征，特别是对冬季黑潮入侵南海东北部的动力过程，同化结果有了更准确的描述。同时，另一个重要的修正表现在：同化试验中瞬变的中等尺度涡旋得到加强，体现了南海海洋天气尺度涡被资料同化所“唤醒”(trigger)。这种“唤醒”不仅明显地反映在表层环流场中，对南海次表层动力、热盐结构也有一定的影响。

The Princeton Ocean Model(POM) is applied here t o assimilate TOPEX/Poseidon altimeter data in the South China Sea(SCS) in winter with a blending scheme.The blending coefficient,which weighs TOPEX sea surface height( SSH)over the modeled value,is derived from the standard deviations in SSH both f rom the response of POM to winter monsoon forcing and corresponding TOPEX data.Comparison between the control run and the assimilating run indicates that blend i ng TOPEX altimeter data can modify reasonably the large scale circulation in the SCS,such as the dynamic process relevant to the impact on the northeastern SCS caused by Kuroshio's intrusion.In the assimilating run the mid scale eddy activity is enhanced due to the more synoptic eddies in the SCS,triggered by such blending assimilation.Modification can be found in both the dynamic and thermal str uctures,not only at the surface,but also at the sub surface.