The Impact of the Tropical Indian Ocean on South Asian High in Boreal Summer
The Impact of the Tropical Indian Ocean on South Asian High in Boreal Summer
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DOI：
10.1007/s00376-010-9224-y
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发表时间：
2011-02
影响因子：
5.8
通讯作者：
Huang Gang;Qu Xia;Huang Kaiming
中科院分区：
文献类型：
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作者：
Huang Gang;Qu Xia;Huang Kaiming
热带印度洋（TIO）在夏季厄尔尼诺现象减弱时或之后比正常情况下温暖。本文研究了夏季TIO海温对南亚高压的影响。当TIO较暖时，南亚高压加强，中心南移。结果表明，降水异常不能解释南亚高压的变化。提出了一种可能的机制来解释TIO和SAH之间的联系：TIO的海温升高改变了大气边界层的等效位温，改变了湿大气的温度廓线，使对流层变暖，从而在南亚地区产生显著的正高度距平，并对南亚高空产生修正。在TIO和南亚地区具有较好的预报能力的TIO SST对南亚高压的影响进行了检验。在TIO上理想化加热的实验再现了SAH对TIO变暖的响应。结果表明，TIO诱导的ABL EPT变化可以解释SAH的变化。
The tropical Indian Ocean (TIO) is warmer than normal during the summer when or after the El Niñno decays. The present study investigates the impact of TIO SST on the South Asian High (SAH) in summer. When the TIO is warmer, the SAH strengthens and its center shifts southward. It is found that the variations in the SAH cannot be accounted for by the precipitation anomaly. A possible mechanism is proposed to explain the connection between the TIO and SAH: warmer SST in the TIO changes the equivalent potential temperature (EPT) in the atmospheric boundary layer (ABL), alters the temperature profile of the moist atmosphere, warms the troposphere, which produces significant positive height anomaly over South Asia and modifies the SAH.An atmospheric general circulation model, ECHAM5, which has a reasonable prediction skill in the TIO and South Asia, was selected to test the effects of TIO SST on the SAH. The experiment with idealized heating over the TIO reproduced the response of the SAH to TIO warming. The results suggest that the TIO-induced EPT change in the ABL can account for the variations in the SAH.