摘要
用NCEP/NCAR逐月再分析资料和中国560站月降水资料,定义了一个高原季风指数IPM2。结果表明:与原有高原季风指数相比,该指数与四川盆地夏季降水的相关性更好,能够较好地反映四川盆地夏季降水的异常变化。当高原夏季风偏弱时,巴尔喀什湖至贝加尔湖低压槽、亚洲东岸高压脊、印度低压均加强,同时西太平洋副热带高压偏北,来自孟加拉湾的西南风水汽输送和源于西太平洋的偏南风水汽输送均加强,这种环流形式有利于四川盆地西(东)部夏季降水偏多(少);当高原夏季风偏强时,情况相反。IPM2弱(强)大(小)年与四川盆地西(东)部涝年环流背景相似,表明IPM2能够很好反映四川盆地夏季降水异常的环流场特征。
Based on monthly NCEP/NCAR reanalysis and precipitation of 560 stations in China,a new plateau monsoon index IPM2 is defined,and its characteristics,advantages,characteristics of anomalies and its effect on summer precipitation in Sichuan basin are analyzed.The results show that： compared to the original plateau monsoon index,IPM2 has a better correlation with the summer precipitation in Sichuan basin and can reflect the change of summer precipitation in Sichuan basin better.In the weak index years of IPM2,the low trough between Balkhash and Baykal,the ridge located in the east coast of Asia and the Indian low all strengthened,the subtropical high appeared more northward than usually,the southwesterly water vapor transport from the of Bengal and southerly water vapor transport originated from West Pacific Ocean strengthened,all these are favorable to a lot of rain in the west Sichuan basin and little rain in the east.In the strong index years of IPM2,the situation is opposite.The overall circulation background of IPM2 weak（strong） index years and flood years in West（East） basin are basically consistent,which shows that IPM2 can reflect characteristics of summer precipitation anomalies in Sichuan basin very well.
出处
《气象科学》
CSCD
北大核心
2010年第3期308-315,共8页
Journal of the Meteorological Sciences
基金
国家自然科学基金(40375031)
关键词
高原季风指数
相关
夏季降水
Plateau monsoon index Summer precipitation
