南亚高压脊线南北活动规律数值试验

南亚高压是夏季北半球100 hPa上准定常的、超长波性质的环流系统。在100 hPa上,高压冬半年位于10°N西太平洋上空,这期间强度较弱,对我国天气影响不大。入春以后,高压开始向西北移动,强度逐渐增强;夏季7月份,高压脊线位于32°N,60°E;7-8月,高压开始东撤,脊线基本稳定在30°N左右;入秋以后,高压中心回到海洋上空,逐渐退至26°N。在这个过程中,南亚高压有明显的南北向季节性移动。

NUMERICAL SIMULATION OF MERIDIONAL SHIFT OF SOUTH ASIA HIGH RIDGE LINE

The seasonal meridian-shift of South Asia High Ridge Line is investigated by means of a zonal average model,which is subjected to the assumption of a geostrophically balanced zonal wind. The dynamic influences and the role of heat source connected with the topographys are discussed through the z-σ coordinates. The sea surface heating on the bay of Bangal and the condensation heating above there are also studied.As a consequence, the simulating zonal circulations which are in rather good agreement with the actual situations above Tibetian Plateau in summer are obtained, and some interesting conclusions about meridional Shift of South Asia High Ridge Line are given.