2018年6月青岛海域一次海雾过程分析

Analysis of a Sea Fog Event Along the Coast of Qingdao in June 2018

利用青岛地面观测站资料、NCEP全球再分析数据、卫星云图等资料,对2018年6月79日青岛附近海域出现的一次海雾过程进行分析。结果表明:本次海雾过程的天气形势属于低槽东移型,在海雾持续时段,相对湿度接近100%;风速风向、海表面温度、气海温差等条件均为黄海海域平流冷却雾的典型配置。利用中尺度WRF模式对本次海雾进行模拟,在海雾维持阶段,逆温层始终存在,且逆温层高度和强度与海雾强度成正比;云水混合比较好地反映了海雾过程中浓雾的范围,在最高0.6 g·kg-1以上的云水混合比高度明显抬升时段,海雾同步达到最强。利用HYSPLIT-4模式对青岛附近气块进行后向追踪可知,本次海雾高层不同高度的气块在青岛上空都经历了明显的下沉增温过程,有利于逆温层的维持和发展;低层气块来自东海,在东南风的作用下,不断将暖湿空气输送至青岛海域。

Based on the surface observations from Qingdao station,NCEP reanalysis data,satellite images,etc.,a case of sea fog process that occurred over the Yellow Sea near Qingdao from 7 to 9 June 2018 is studied.The results show that the synoptic patterns of this sea fog process belonged to the low-trough eastward-shifting type.During the duration of the sea fog,the relative humidity was close to 100%.Other conditions such as wind speed and direction,sea surface temperature and air-sea temperature difference were all consistent with the typical configuration of the advection cooling fog over the Yellow Sea.Besides,the WRF model is employed to conduct the numerical simulation of this sea fog.The findings are that,in the sea fog maintenance stage,the inversion layer existed all the time,and the height and intensity of the inversion layer were proportional to the density of the sea fog.The cloud-water mixing ratio agreed well with the sea fog range,especially when the ratio was higher than 0.6 g·kg-1,the sea fog reached the densest stage.Then,the air mass back trajectory is done by the HYSPLIT-4 back trajectory model,and the result shows that the air masses of different upper layers during the sea fog process experienced a significant sinking and warming process aloft Qingdao,which was conducive to the maintenance and development of the inversion layer.The lower-layer air mass came from the East China Sea,continuously transporting warm and humid air to Qingdao under the effect of southeasterly winds.