气象2012，Vol.38Issue(8)：913-920,8.
2011年隆冬北京初雪成因分析
An Analysis of Dynamic Characteristics of the First Snow in Winter 2011 in Beijing
摘要
Abstract
In this paper, an analysis is performed on the snow weather process taking place in Beijing on February 9 and 10, 2011. The NCEP final operational global analysis data as well as the observation data, both conventional and densely AWS data, are used in the analysis. It is shown in the analytical results that this snow process is a combined consequence of the eastward returning current and the surface inverted trough. The eastward returning current is characterized by its wedge structure of being shallow in north- west direction and deep in southeast direction, as well as being wet and cold. Although there is convergent ascending current and frontogenesis, the eastward returning current is not the primary dynamic mechanism of the snowfall. Instead, it plays the role as a cooling and wetting cushion. There are three primary dy- namic mechanisms. First, a positive vorticity advection in front of 500 hPa short wave trough and a tem- perature advection at 850 hPa facilitate the development and eastward movement of surface inverted trough near Hetao. Second, the southwest current at east side of inverted trough ascends on the cooling cushion. Third, the overlay of convergent rising regions at the inverted trough and the front of east wind makes as- cending motion strong. Finally, southwest warm and wet currents serve as the main water vapor source for the snow process.关键词
北京初雪/东风回流/地面倒槽/水汽Key words
first snow/eastward returning current/inverted trough/water vapor分类
天文与地球科学引用本文复制引用
董林,符娇兰,宗志平..2011年隆冬北京初雪成因分析[J].气象,2012,38(8):913-920,8.基金项目
中国气象局2011年预报员专项（CMAYBY2011-057）项目、公益性行业（气象）科研专项（GYHY200906001、GYHY201006010-2）和国家自然科学基金青年科学基金项目（41105030）共同资助 （）
