江苏省秋冬季强浓雾发展的一些特征

运用江苏省72个国家基本气象观测站和339个交通气象观测站资料,对2013年12月1-9日、2015年10月23日、12月22日及2016年2月12日出现的四次全省性的以辐射降温为主的强浓雾和特强浓雾过程进行分析,筛选出194个站例,对江苏省秋、冬季强浓雾生消的气候特征、雾爆发增强的微物理特征及雾爆发性增长的触发因子进行分析。结果表明:(1)雾爆发性增强的本质是雾在很短时间内雾滴增多增大,雾含水量呈几个数量级的增加,从而导致雾区能见度快速下降。(2)夜间辐射降温突然增强、底层弱冷空气入侵、日出后蒸发量加大及湖陆风效应是雾爆发性增长的触发因子。

Some Characteristics of the Development of Heavy Fog in Autumn and Winter in Jiangsu Province

Using the high spatio temporal meteorological observation data from 339 traffic weather stations along highway, and 72 conventional observation stations, four heavy fog events during 1-9 December 2013, on 23 October 2015, 22 December 2015 and 12 February 2016 are analyzed. Based on 194 cases, climatic characteristics of extremely heavy fog in initiation and disappearance, microphysical characteristics of explosive enhancement and the triggering factors of heavy fogs are analyzed. The results show that visibility dropped sharply within very short time (in 30 min) because fog droplet number concentration, water content and droplet size increased remarkably, and fog droplet spectrum became broader. In addition, the sharp drop of temperature resulted from radiation reinforcement at night, the weak cold advection of underlying layer, the increase of evaporation after sunrise, and the lake land wind effect made fog reinforce eruptively.