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闽南沿海一次春季海雾过程微物理特征分析
张伟1, 胡雅君2, 荀爱萍1, 陈德花2, 孙学金3
(1.海峡气象开放实验室, 厦门市气象台;2.海峡气象开放实验室,厦门市气象台;3.国防科技大学气象海洋学院)
Microphysical feature Analysis of a Spring seafog event in southern coastal area of Fujian
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投稿时间:2020-04-05    修订日期:2020-12-07
中文摘要: 利用地面自动站观测、风廓线雷达、ERA5再分析资料、葵花8高分辨率卫星资料以及FM-120型雾滴谱资料,分析了2019年4月7日闽南沿海一次强浓雾过程的环流形势以及微物理特征。环流形势分析表明,此次海雾过程500hPa为槽底偏西~西北气流,700Pa至地面为一致的偏南气流,探空形势稳定.海雾发生前,整层整层风速明显减小,弱风速层厚度迅速增大,为海雾的形成提供了稳定的环流背景。卫星监测分析表明,海雾首先快速形成于台湾海峡上,在偏南气流作用下,平流至沿海地区。水文条件分析表明,福建近海存在一条冷水带,从海峡中部至沿海海温梯度大,海温在18~24 ℃之间,近海气海温差介于0~2 ℃之间,有利于海峡内平流冷却雾的形成。雾滴谱分析表明,翔安站能见度显著下降伴随着粒子数浓度、液态含水量显著增加,雾滴谱爆发性拓宽。海雾过程中,5分钟平均粒子数浓度最大超过200个?cm-3,瞬时数浓度最大达到468个?cm-3,雾过程平均数浓度为100 个?cm-3。5分钟平均液态水含量最高达到0.41 g?m-3,瞬时液态水含量最大达到1.35 g?m-3,雾过程平均液态水含量为0.17 g?m-3。粒子浓度呈现双峰结构特征,峰值分别位于4~6 μm、22~26 μm区间,表明小粒子和大粒子对海雾的形成均有明显的贡献。
Abstract:Based on the data of automatic weather station, wind-profiling radar, ERA5 reanalysis, himawari 8 high resolution satellite and FM-120 fog droplet spectrometer, we discussed the circulation pattern and microphysical processes of an seafog event in southern coastal area of Fujian in April 7th 2019. Circulation analysis showed that this sea fog event occurs under the control of west to northwest flow of 500 hPa trough bottom, while 700 hPa to surface was uniform southerly flow. The sounding situation is stable. Before sea fog event, low level wind speed decreased significantly, increasing the thickness of low wind speed, which provided stable circulation for sea fog. Himawari 8 satellite images showed that the sea fog rapidly formed on straits first and then advected to coastal area by low level southerly airflow. Hydrological analysis indicated that there existed a cold water band and large temperature gradient near shore. Sea surface temperature(SST) varied between 18 to 24 ℃. Air sea temperature difference varied between 0 to 2 ℃ with sea surface colder than the air above, which contributed to advection sea fog forming. Fog droplet spectrum analysis showed that visibility decreased dramatically while Particle number concentration (PNC), liquid water content (LWC) and droplet spectrum increased significantly at the same time. During the sea fog process, five-minute average PNC exceeded 200 #?cm-3 and instantaneously reached 468 #?cm-3 maximum, Process average PNC reached 100 #?cm-3. Five-minute averaged LWC reached 0.41 g?m-3 and 1.35 g?m-3 instantaneously. Process average LWC reached 0.17 g?m-3. Fog droplet size exhibited double peak characteristic during the fog process with 4~6 μm and 22~26 μm interval. This proved that small and big particles both contributed to the formation of sea fog.
文章编号:202004050108     中图分类号:    文献标志码:
基金项目:国家自然科学基金项目-青年项目(41705045),厦门市气象局海洋气象创新团队共同资助
引用文本:
张伟,胡雅君,荀爱萍,陈德花,孙学金,0.Microphysical feature Analysis of a Spring seafog event in southern coastal area of Fujian[J].Meteor Mon,():-.
Zhang Wei,Hu Yajun,Xun Aiping,Chen dehua,Sun Xuejin,0.Microphysical feature Analysis of a Spring seafog event in southern coastal area of Fujian[J].Meteor Mon,():-.