摘要
利用NCEP资料对2008年1～2月间长江中下游地区发生的持续性暴雪天气过程进行分析,发现中高纬大气环流异常,冷暖空气在长江中下游地区交汇,对流层中低层切变的维持和有利的温度层结是持续性低温雨雪天气和暴雪产生的必要条件。在此基础上再对该区域的水汽输送特征进行重点分析,可知:水汽从孟加拉湾沿云贵高原或越过中南半岛到内陆,以及从南海绕过中南半岛经转向气流输送,北上进入长江中下游地区两条通道行进;与夏季梅汛期长江中下游地区水汽输送不同,冬季的水汽输送通道随高度有明显的变化,水汽主要是由西边界进入该地区,主要水汽辐合发生在850 hPa以上。而孟加拉湾和南海作为主要水汽来源,前者在中高层作用明显,而在低层后者的比重较大。
Based on NCEP reanalysis data,the characteristics of weather situation and moisture transfer over the lowermiddle reaches of Yangtze River during January to February of 2008 are studied. The results show that the circulation abnormal of middle-high latitude,hot and cool air mixed,maintenance of the shear line on lower middle levels of troposphere and the beneficial temperature stratification were the requirement. Based on this,the reaches show it was related to the exceptionally intense moisture transfer in the southern area of China; the Yunnan-Guizhou Plateau and the South China Sea are the two main channels of the moisture from the Bay of Bangle that finally enter the lower-middle reaches of Yangtze River. After calculating the water-vapour budget,it is also found that the channels of the moisture transfer vary with the altitude obviously, which is different from the one in Meiyu Period, and the water-vapour flows mainly from west boundary into the area and the water-vapour convergence occurrs above the layer 850 hPa. The Bay of Bangle is an important moisture source above the layer of 850hPa while the South China Sea is the one that blow the layer.
出处
《科技通报》
北大核心
2010年第5期787-794,共8页
Bulletin of Science and Technology
基金
浙江省青年课题(2009QN08)资助
关键词
长江中下游
持续性
暴雪
切变线
温度层结
水汽输送
水汽收支
lower-middle reaches of Yangtze River, sustain, heavy snow, shear line, temperature stratification, moisture transfer, water-vapour budget
