南海及菲律宾地区异常加热对南亚环流的影响

THE INFLUENCES OF ANOMALOUS HEAT SOURCE OVER THE SOUTH CHINA SEA AND PHILIPPINES ON SOUTH ASIAN GENERAL CIRCULATION

本文考虑南海及菲律宾地区上空热源异常,取用P—σ混合坐标系五层原始方程模式,进行数值试验,结果表明,这种异常热源将使南亚环流发生显著变化。在异常图型上,这些变化主要有:在该地上空出现加热时,对流层中低层我国华南有气旋性辐合带,我国大陆中部及日本地区为反气旋环流控制。显然,这种环流对华南降水有利。诊断分析进一步指明,华南辐合带的形成除与异常加热直接有关外,温度平流也有显著作用;日本和我国大陆中部反气旋环流的形成是异常加热区域上升的空气在其北侧下下沉的结果。

In this PaPer, the experiments for considering anomalous heating over the South China Sea and the Philippines have been Performed bv five -level model of the mixing P-σ coordinate system . The results show that heating over those zone occurres, the South Asian general circulation changes. The changes revealed on the anomalous Pattern are mainly: when anomalous heating occurres there is a convergence zone over South China (along 20° -25° N)and the anticyclonic circulation dominate over central China and Japan inmiddle-low troposp here. Evidently, the anomalous circulation is fa orable for the formation of the rainfall over South China. The diagnostic results further indicate that the temperature advection Plavs an evident role on the formation of the convergence zone over South China in addition to the relation with the anomalous hea-t ing; the ascending airs fromheating zone descend over central China and Japan and so that the anticyclonic circulation mav be formed there.