东亚冷涌期间低纬环流和降水形成的数值试验

NUMERICAL EXPERIMENTS ON THE FORMING MECHANISMS OF LOW LATITUDE CIRCULATION CELLS AND PRECIPITATION DURING EAST ASIAN COLD SURGE

应用数值试验的方法，研究了东亚冷涌期间低纬环流和降水的形成。结果表明：低纬积云对流作用加强了东北季风和东北信风，但阻滞了热带辐合带进一步南移。印尼和澳大利亚北部季风降水可以独立存在。南海冷涌以及越赤道的西太平洋东北信风都可以是澳大利亚北部夏季风及降水形成的重要因子。数值研究还指出；印尼加里曼丹的强季风降水及常驻性低层扰动形成的基本因子是南海冷涌所触发的积云对流发展。印尼、加里曼丹地形及东北信风扰动可影响该处降水的强度。

n this paper,the forming mechanisms of low latitude circulation cells and precipitation during east Asian cold surge have been studied by using a five-layer primitive equation model. Numerical experiments show that:in low latitude,the cumulus convection effects can intensify the north-east monsoon wind and north-east trade wind,keep ITCZ from transferring southward further.Numerical results indicate that the winter monsoon precipitation in indonesia and North-Australia can exist independently. To form the North-Australian summer monsoon wind and its precipitation,both the South China Sea(SCS) cold surge and the west Paci-fic north-east cross-equatorial trade wind can be of importance.Numerical results also indicate that: the development of cumulus convection, triggered by the SCS cold surge,is a fundamental factor in forming the strong monsoon precipitation and low-level stationary disturbances over indonesia and Borneo. The lands of Indonesia and Borneo and the north-east trade wind disturbance are two important factors affecting the precipitation intensity.