江苏北部不同等级雾的微物理结构及个例分析  

Microphysical structure of fog droplets in different levels of fog and a case study in northern Jiangsu province

作　　者：祖繁[1] 袁成松[1] 吴泓 王宏斌[1] 朱毓颖[1] 朱承瑛[1] ZU Fan;YUAN Chengsong;WU Hong;WANG Hongbin;ZHU Yuying;ZHU Chengying(Key Laboratory of Transportation Meteorology,CMA/Jiangsu Institute of Meteorological Sciences/Nanjing Joint Institute for Atmospheric Sciences,Nanjing 210009,China)

机构地区：[1]中国气象局交通气象重点开放实验室/江苏省气象科学研究所/南京气象科技创新研究院,南京210009

出　　处：《气象学报》2020年第4期691-704,共14页Acta Meteorologica Sinica

基　　金：国家自然科学基金项目(41575135);江苏省重点研发计划(社会发展)项目(BE2016810);江苏省自然科学基金项目(BK20161073);江苏省气象局北极阁基金项目(BJG201701、BJG201703、BJG201606)。

摘　　要：利用2015-2017年秋冬季在江苏北部观测到12次雾过程的雾滴谱数据及常规气象观测资料,统计分析了轻雾、大雾、浓雾、强浓雾和特强浓雾等级下的微物理特征量及雾滴谱分布,并通过一次雾过程的分析,探讨了不同雾等级下的主要微物理过程。结果表明:随着雾等级的提升,雾滴数浓度、含水量增长明显,而轻雾、大雾和浓雾的雾滴平均直径和最大直径差异不大,但当能见度小于200 m时,平均直径和最大直径显著增大;能见度下降时,平均数浓度谱和含水量谱的谱线上抬,从浓雾到强浓雾,粒径大于10μm的大雾滴增长明显;雾滴数浓度主要由小雾滴控制,雾滴含水量受大雾滴影响;东海县郊平均的雾滴含水量与南京观测结果相差不大,但雾滴数浓度仅为南京的一半左右,平均直径大约是南京的2.3倍;个例分析中,能见度从1000 m下降到50 m,凝结核活化并凝结增长是主要微物理过程,但可凝结水汽是影响该过程效果的一个重要因子,可使雾滴数浓度和平均直径呈现不同的相关关系;能见度降到50 m以下时,碰并过程效果显著;日出后雾滴蒸发作用显现并逐步增强。Using fog droplets spectrometer data and conventional meteorological elements observed in 12 fog events in northern Jiangsu province during autumn and winter from 2015 to 2017,the microphysical characteristics and fog droplets spectra were analyzed for light fog,fog,heavy fog,dense fog and extremely dense fog.Dominant microphysical processes during fogs of different levels were discussed based on analysis of a long-lasting fog case.The results indicate that the droplets concentration and liquid water content increase significantly with the enhancement of fog level,while the droplets mean diameter and maximum diameter are similar for light fog,fog and heavy fog until the visibility decreases to less than 200 m,after which mean diameter and maximum diameter both show an obvious increase.When the visibility deteriorates,the average droplet spectra of the number concentration and liquid water content both are uplifted,and the big droplets with diameter greater than 10μm grow notably from heavy fog to dense fog.The number concentration of fog droplets is mainly controlled by small droplets,and the liquid water content is affected by large droplets.The average liquid water content of fog droplets in Donghai county suburb is comparable to that in Nanjing,but the number concentration is only about half of that in Nanjing and the mean diameter is about 2.3 times of that in Nanjing.In the case study,condensation nuclei activation and subsequent condensational growth are the dominant microphysical process during the period of visibility decreasing from 1000 m to 50 m.However,the condensable water vapor is an important factor affecting the effect of the process,which can make the number concentration and the mean diameter show different correlations.When the visibility drops below 50 m,the effect of collision-coalescence process is remarkable.After sunrise,droplet evaporation appears and gradually reinforces.

关 键 词：能见度 雾等级 微物理结构 物理过程 江苏北部 

分 类 号：P426.4[天文地球—大气科学及气象学]