摘要
The feature of the decadal movement of the Meiyu belt and their association with East Asia atmospheric circulation for the period of 1979―2007 is examined in this study. It is shown that the Meiyu belt of China has a decadal shift in the late 1990s. There is a remarkable difference between the periods before and after 1999, with the Meiyu belt mainly located to the south of the Yangtze River valley before 1999, but afterward mainly located in the Huaihe River valley. At the same time, a distinctive tropospheric warming and stratospheric cooling trend is found in the mid-latitudes of East Asia, which causes the upper tropospheric pressure surfaces upward bulging and the tropoause elevated in the subtropics and associated widening of the subtropical area over East Asia. Accompanying the subtropics widening, the subtropical westerly jet over East Asia shifts northward and the East Asia tropical Hadley circulation expands poleward, which results in the northward shift of the Meiyu belt.
The feature of the decadal movement of the Meiyu belt and their association with East Asia atmospheric circulation for the period of 1979―2007 is examined in this study. It is shown that the Meiyu belt of China has a decadal shift in the late 1990s. There is a remarkable difference between the periods before and after 1999, with the Meiyu belt mainly located to the south of the Yangtze River valley before 1999, but afterward mainly located in the Huaihe River valley. At the same time, a distinctive tropospheric warming and stratospheric cooling trend is found in the mid-latitudes of East Asia, which causes the upper tropospheric pressure surfaces upward bulging and the tropoause elevated in the subtropics and associated widening of the subtropical area over East Asia. Accompanying the subtropics widening, the subtropical westerly jet over East Asia shifts northward and the East Asia tropical Hadley circulation expands poleward, which results in the northward shift of the Meiyu belt.
基金
Supported jointly by National Basic Research Program of China (Grant No. 2006CB403604)
the National Key Technology R&D Program (Grant Nos. 2007BAC03A01 and 2006BAC02B04)
