中南半岛对流对南海夏季风建立过程的影响

Impact of the Convection over the Indo-China Peninsula on the Onset of SCS Summer Monsoon

利用RegCM2模式进行数值试验 ,得到中南半岛对流对北半球副高带断裂、进而对孟加拉湾对流建立具有重要影响 ,而孟加拉湾对流建立后激发的Rossby波列又是南海夏季风建立的主要因子之一。进一步分析中南半岛对流、副高带断裂及南海夏季风建立的年际变化 ,得到中南半岛对流的强弱 (活跃的早晚 )与副高带在孟加拉湾北部断裂及南海夏季风爆发的早晚有密切关系。它们还与海温异常及纬圈环流的变化相联系 :当赤道中东太平洋海温偏暖 (冷 )时 ,Walker环流偏弱 (强 ) ,中南半岛对流偏弱 (强 ) ,副高带断裂偏晚 (早 ) ,南海夏季风建立偏迟 (早 )。

The RegCM2 model is used to investigate the effect of the convection over the Indo-China Peninsula (CICP) on the onset of South China Sea (SCS) summer monsoon. It is suggested that CICP could significantly influence the splitting of the subtropical high (SH) belt and then influence the convection over the Bay of Bengal (BOB). The Rossby-wave chain triggered by the convection over BOB might be a main factor for the onset of SCS summer monsoon. By analysing the interannual changes of the events mentioned above the results show that the intensity of CICP (or the timing of strong convection) is closely related to the timing of the splitting of SH belt and the onset of SCS summer monsoon. These events are also associated with the sea surface temperature (SST) anomaly and zonal circulations. When SST in the east-central equatorial Pacific is warmer (colder), the Walker circulation and CICP are weaker (stronger), the splitting of SH belt occurs later (earlier) and SCS summer monsoon bursts later (earlier).