摘要
将NECP/NCAR资料中850 hPa纬向风分量进行30~60天带通滤波,用大气季节内振荡(ISO)来表征东亚夏季风涌的活动特征。研究表明,长江中下游地区和淮河流域分别出现涝年时,都伴有很显著的季风涌向北传播的特征。季风涌的北传实质就是季风中来自热带地区ISO的向北传播。季风涌北传过程中,得到来自东西两侧纬向传播的ISO补充。纬向传播的ISO在110°E^120°E附近汇合后增强自热带地区向北传的季风涌,使得季风涌在经向上可以继续向北传播,并对我国东部地区夏季大尺度降水过程产生一定的影响。纬向补充的ISO特征差异对我国东部大尺度降水位置会产生一定的差异。
The NCEP/NCAR 850 hPa zonal wind reanalysis data are calculated by using the band-pass filter to study the atmospheric intraseasonal oscillation, which can express the activity character of the East Asian summer monsoon stream. The results show that the mid to lower reaches of the Yangtze River and the Huaihe River basins during the flood years are characterized by the monsoon stream propagating northward. The essence of it is the Intraseasonal Oscillation （ISO） in the monsoon transfer from the tropical region to northward. In the northward propagation courses of the monsoon stream it is supplied by the ISO, which has zonal east and west propagations. The ISO in the zonal propagation will converge in 110°E- 120°E, and then reinforces the ISO which propagates northward here. This reinforcement can make the ISO keep on propagating northward, which will have some influence on the summer large-scale precipitation course in eastern China. Otherwise the difference of the ISO zonal reinforcement may result in the difference of large-scale rainfall positions in eastern China.
出处
《大气科学》
CSCD
北大核心
2007年第6期1129-1139,共11页
Chinese Journal of Atmospheric Sciences
基金
国家重点基础研究发展规划项目2006CB403603
2004CB418302
国家自然科学基金资助项目40675056
关键词
季风涌
季节内振荡
纬向传播
经向传播
大尺度降水
monsoon stream, intraseasonal oscillation, zonal propagation, meridional propagation, large-scale precipitation
