夏季季风降水凝结潜热释放效应对西太平洋副高形成和变异的影响

通过分析 1 998- 0 5～ 1 998- 0 8再分析资料 ,得知夏季西太平洋副高的准定常结构和瞬变结构有着显著的不同。月平均西太平洋副高中心为上升气流 ,逐日资料则表现出下沉气流 ,下沉气流主要是由西太平洋副高北侧雨带中降水潜热释放效应所致的上升气流在高空下沉产生的。据此认为夏季中国华东、华南地区的季风降水凝结潜热释放所致的上升气流在西太平洋副高中心区的下沉运动是西太平洋副高维持和发展的重要原因。将逐日西太平洋副高面积、西伸指数与对流降水率资料进行了滞后相关分析 ,结果表明西太平洋副高的西伸与外围雨带之间存在着显著的相互影响。

EFFECT OF SUMMER MONSOON PRECIPITATION LATENT HEAT RELEASE ON THE FORMATION AND VARIATION OF WESTERN PACIFIC SUBTROPICAL HIGH

WT5BZ]Based on the daily reanalysis data from May to August in 1998,it is found that the transient and quasi permanent structures are different from each other for western Pacific subtropical high(WPSTH).The downdraft in WPSTH center in daily data is mainly caused by the latent heat release in its northern monsoon rainbelt which gives rise to ascending motion there and descending motion in the center,therefrom explaining the mechanism of WPSTH formation and variation.The lagging correlation analysis between convective precipitation rate and area index, and westward extension index of WPSTH indicates that the obvious interaction exists between the westward extension of WPSTH and its surrounding rainbelt. WT5HZ]