上海近海一次低压控制下春季海雾空间差异分析  

Analysis of spatial difference of a spring sea fog event offshore Shanghai under the effect of a low pressure system

作　　者：王紫竹 胡松[1,2,3] 刘旺 WANG Zi-zhu;HU Song;LIU Wang(College of Marin Sciences,Shanghai Ocean University,Shanghai 201306 China;National Engineering Research Center for Oceanic Fisheries,Shanghai 201306 China;Shanghai Engineering Research Center for Estuarine and Oceanographic Mapping,Shanghai 201306 China;Shanghai Marine Meteorological Center,Shanghai 201306 China)

机构地区：[1]上海海洋大学海洋科学学院,上海201306 [2]国家渔业工程技术研究中心,上海201306 [3]上海河口海洋测绘工程技术研究中心,上海201306 [4]上海海洋气象台,上海201306

出　　处：《海洋预报》2020年第1期33-42,共10页Marine Forecasts

基　　金：农业部项目(D-8002-15-8003-2);全球变化研究国家重大科学研究计划项目(2015CB953901);海洋环境安全保障国家重点研发计划项目(2018YFC1406801)。

摘　　要：根据海上浮标实测数据和再分析数据,发现2016年4月20-23日长江口航道附近南北海雾存在的显著空间差异主要受到水汽以及风场的影响。分析表明:(1)本次海雾过程高空受低压槽控制近地面处低压过境,切变线东移导致低空风向的迅速转变,此后受到暖锋影响,导致短时小雨过程的发生;(2)此次海雾过程受风场的影响较大,盛行南风时水汽充足,湿度较大,容易产生海雾,受西北风主导时,则容易出现海雾消散的情况;(3)长江口外北部站点和南部站点存在显著空间差异性,北部站点能见度明显好于南部站点,并且在此次海雾过程中北部站点先于南部站点出现一次能见度好转的情况,这是由于低压过境导致风向骤变,北部未获得充分的水汽供给所致。此次低压槽天气过程在长江口南北产生区域差异显著的海雾,对这种典型风向骤变过程分析有助于为航运密集的长江口海雾预报提供参考。Based on the marine buoy observations and reanalysis data, we found that the evident spatial difference of sea fog(the complex generation-dissipation process from April 20 th to 23 rd 2016)between north and south stations offshore the Yangtze Estuary was mainly caused by vapor transport and wind field. The results show that the sea fog process was influenced by rapid change of wind direction caused by the passage of a low pressure system, which was controlled by low pressure trough and transient rain resulted from warm fronts. The sea fog process was mainly influenced by wind direction. The moist south wind favors the development of sea fog, while dry northwest wind undermines the development of sea fog. The visibility between north and south stations offshore the Yangtze Estuary was significantly different. The visibility of north station turned to normal earlier than that of south station, since the wind direction suddenly changes and the north station did not received sufficient water vapor supply during the low-pressure passage. By analyzing sea fog difference between north and south stations influenced by low pressure trough, this study helps our understanding for sea fog forecast offshore the Yangtze Estuary in the future, especially for the weather processes characterized by the swift change of wind direction.

关 键 词：海雾 上海长江口 浮标观测 低压槽 风向骤变 

分 类 号：P732[天文地球—海洋科学]