青藏高原热状况对南亚高压活动的影响

EFFECT OF THERMAL REGIME OVER THE TIBETAN PLATEAU ON SOUTH ASIA HIGH ACTIVITIES

本文分析了青藏高原下垫面与高原上空热状况变化的异同及其二者与南亚高压的关系。指出青藏高原下垫面热状况与高原上空热状况年际变化的一致性及月际变化的差异——青藏高原下垫面从2月就开始大幅度增温,而高原上空5月才开始突发性增温。高原下垫面降温幅度最大的月份出现在11月,高原上空则出现在10月。分析还指出,青藏高原下垫面热状况与南亚高压南北振荡,青藏高原上空热状况与南亚高压东西振荡有密切关系。并且前期青藏高原上空热状况较高原下垫面热状况对南亚高压的预报更具有指示意义。

In this paper, the thermodynamic influence of the Tibetan Plateau on South Asia high is discussed based on the analyses of the thermal regimes in the atmosphere over the Plateau and its underlying surface. It is pointed out that the interannual change of temperature in the atmosphere is consistent with that of the underlying surface, but the inter-monthly changes are different. The temperature of the underlying surface rises sharply from February, while the explosive warming in the atmosphere happens in May. The maximum of temperature decreasing in the atmosphere appears in October, and in November for the underlying surface. It is also found that the latitudinal and longitudinal oscillations of South Asia high are closely tied with the thermal regimes in the atmosphere over the Tibetan Plateau and its underlying surface respectively. The thermal regimes in the atmosphere over the Tibetan Plateau seems to be more useful than the latter for the forecast of South Asia high.