山东一次持续性平流辐射雾过程特征及成因分析

Analysis of the characteristics and causes of a sustained advection-radiation fog process in Shandong

2017年1月1—5日,山东出现了一次大范围的平流辐射雾过程。利用山东地区自动气象站观测资料、青岛探空站资料、风廓线雷达资料和NCEP/NCAR再分析资料,通过分析此次连续大雾过程的大尺度环流背景场、温湿场特征,地面、高空气象要素条件,揭示了其形成原因、维持机制和消散机理。结果表明:中高纬度平直的大气环流、静稳的垂直结构是此次大雾形成的背景条件;水汽输送阶段变化造成的低层水汽浓度变化是大雾阶段变化的原因;两次弱低槽冷锋过程显著增加了雾的强度和范围,也使雾的性质由平流雾变为辐射雾。当低层水汽持续减少,中低层东风气流增强并破坏了大气的稳定层结时,大雾逐渐消散。

A large range of 5-day advection-radiation fog weather occurred in Shandong Peninsula from 1 to 5 January 2017.By analyzing the large-scale circulation,the temperature and humidity field,and surface and upper meteorological elements,the formation,maintenance,and dissipation of the fog are revealed based on automatic weather station data in Shandong,sounding data and wind profile radar data in Qingdao as well as conventional observation data and NCEP/NCAR reanalysis data.The results are as follows.The flat atmospheric circulation in middle and high latitudes and the static atmospheric vertical structure are the background conditions of this fog.The density change of the water vapor resulting from the phase change during its transfer causes the phase change of the fog.Two weak cold front processes significantly enhance the intensity of the fog and expand its effect range,and also make the advection fog develop into a radiation one.When the moisture on the low layer declines and the easterly wind speed on the boundary layer increases and destroys the stable atmospheric stratification,the fog gradually dissipates.