摘要
利用IAP9L AGCM模式对印度夏季风风场进行了数值模拟,基本上模拟出了印度夏季风系统中各风系分布;在此基础上,通过改变模式中非洲大陆的地形高度,设计了一组地形敏感性试验,对比了敏感性试验和控制试验的结果,分析非洲地形高度对印度夏季风的影响。结果表明,非洲地形高度升高使得阿拉伯海热带区域、南印度洋副热带区域和非洲大陆东南部在低层分别出现异常反气旋、气旋和反气旋环流,这些异常环流使非洲大陆东岸的越赤道气流增强,阿拉伯海热带地区的西风气流增强;地形升高也会使印度半岛区域低层水汽通量辐合增强,整层垂直上升速度加强,降水增加,故非洲地形升高最终导致了印度夏季风增强;而非洲地形高度降低,则情况相反,这充分说明了非洲大陆地形是印度夏季风形成的关键因子。
A numerical simulation of Indian summer monsoon wind field was conducted by using IAP9L AGCM model and the distribution of wind system in monsoon was simulated fundamentally.Based on this,a set of orographic sensitive experiments were further carried out by changing the terrain altitude of African continent.Results suggest that the increase of African terrain height caused the areas of the tropical Arabian Sea,the subtropical South Indian Ocean and the southeastern Africa appear low level abnormal anticyclonic,cyclonic and anticyclonic circulation,which enhanced the cross-equatorial flow around the east coast of Africa and the westerly in Arabian Sea.The elevated Africa terrain also makes the enhancement of low level convergence of moisture flux,entire layer vertical velocity and precipitation in Indian peninsula.Indian summer monsoon is finally enhanced by the effects of increased terrain height.When Africa terrain altitude is decreased,the situation is opposite.It shows that African topography is the key factor in formation of Indian summer monsoon.
出处
《干旱气象》
2013年第1期10-17,共8页
Journal of Arid Meteorology
关键词
印度夏季风
数值模拟
非洲地形
敏感性试验
Indian summer monsoon
numerical simulation
African topography
sensitive experiment
