青藏高原春夏季对流异常及其对西太平洋副高的影响

The anomalous convection over the Tibetan Plateau in spring and summer and its effect on the western PacifiC subtropical high

摘要:

高原冬春季净辐射多寡可以显著影响高原地区大气环流季节转换进程和后期高原对流活动。净辐射偏多,初夏高原同低纬度之间温度梯度反转时间提前,高原对流活跃。夏季高原主体对流异常,可以通过辐散环流造成西太平洋异常的下沉运动,影响副高的强度、南北位置和西伸程度,最终导致夏季降水的异常分布。

Abstract:

The net radiation in winter and spring has significant effect on the succeeding thermal convection and seasonal evolution of general circulation over the Tibetan Plateau.The more the net radiation in s pring over the Plateau,the earlier the reversal of the meridional temperature gradient between the Plateau and low-latitudes in early summer,resulting in the more active convection over the Plateau.Strong convection over the central Plateau in summer leads to the strengthened subsidence in western Pacific,which is responsible for the enhancement and the westward extension of ridge point as well as the maintenance of western Pacific subtropical high to the south of the Yan gtze River.As a result,the anomalous heavy rainfall takes place in the low-mid reaches of the Yangtze River.