热带太平洋外海气耦合作用对东亚夏季风年代际变化的可能影响

Possible impacts of ocean-atmosphere coupling outside the tropical Pacific on interdecadal variation of East Asian summer monsoon

利用1950—2000年逐月观测的热带太平洋海表温度分别驱动NCAR CCM3全球大气环流模式以及该模式耦合SOM(Slab Ocean Model)混合层海洋模式进行长时间积分试验,将两组试验结果相减来研究热带太平洋外海气耦合作用对20世纪70年代中后期东亚夏季风年代际变化的可能影响.模拟结果表明:热带太平洋外的海气耦合作用使得孟加拉湾、南海附近存在反气旋环流异常,导致我国东部存在偏南风异常,从而引起东亚夏季风年代际增强.其中热带印度洋的年代际增暖对东亚夏季风年代际增强有一定影响.

The possible impact of ocean-atmosphere coupling outside the tropical Pacific on the interdecadal variation of East Asian summer monsoon since the late 1970 s are investigated based on the observed monthly tropical Pacific sea surface temperature（ SST） during 1950-2000. The observed SST is used to drive the NCAR CCM3 global atmospheric circulation model and NCAR CCM3 model coupled with Slab Ocean Model（ SOM） for long-term integration,respectively. Based on the subtraction of above two simulated results, ocean-atmosphere coupling effect outside the tropical Pacific are investigated. Simulation results show that the anticyclone anomaly over Bay of Bengal and South China Sea caused by the ocean-atmosphere coupling effect outside tropical Pacific generates the southerly anomalies over east of China,which results in the interdecadal enhancement of the East Asian summer monsoon. The interdecadal warming of tropical Indian Ocean may contribute to the East Asian summer monsoon ＇s enhancement at interdecadal scale,especially.