南海及邻近海域异常海温影响局域大气环流的初步试验

摘要

南海及邻近海域表层海温（SST）异常的气候意义可以通过IAP-AGCM的数值模拟得到反映。数值试验表明，东亚大气环流对这种SST异常的响应具有时变性（或称季节性），在空间上维持一定的经向结构和纬向结构。确切地说,南海冷水年份，即南海和孟加拉湾负距平、西太平洋正距平的年份，2，3月份南海有东北风异常；夏季菲律宾附近维持一个反气旋式的差值环流，它的低频活动造成了这个地区降水场的低频振荡；与环流较一致的是夏季西太平洋副热带高压活动有所减弱、东移，造成了水汽经向输送的异常分布。%The IAP-AGCM was applied to study the climatic significance of the anomalous sea surface temperature (SST) in the South China Sea (SCS) and its adjacent areas. Numerical experiments indicated that the East Asian atmospheric circulation to the SST anomalies is time-dependent and of seasonality, as well as with a reasonable spatial structure. When there are cold SST anomalies in the SCS and the Bay of Bengal and warm anomalies in the western tropical Pacific Ocean, there is anomalous northeasterly over the SCS in February and March. Moreover, there is anomalous anti-cyclonic　circulation (AAC) generated over Philippine in summer. The AACs low frequency variability results in a coherent low frequency activity in the East Asian atmospheric circulation by the way of teleconnection. Accompanying with AAC, the western Pacific subtropical high in summer becomes weak and also shifts eastward than normal, which causes anomalies in the meridional transport of water vapor.