贵州锋面雾的基本特征及静止锋进退对其生消的影响分析  

Analysis on basic characteristics of frontal fog in Guizhou and influence of stationary front on its generation and elimination

作　　者：杨静 杜小玲 朱文达 朱育雷 YANG Jing;DU Xiaoling;ZHU Wenda;ZHU Yulei(Guizhou Meteorological Observatory,Guiyang 550002)

机构地区：[1]贵州省气象台,贵阳550002

出　　处：《暴雨灾害》2020年第5期496-507,共12页Torrential Rain and Disasters

基　　金：国家自然科学基金项目(41565001)。

摘　　要：利用2000—2013年贵州省84个国家级气象观测站雾的记录、NCEP/NCAR再分析资料以及高空、地面常规观测资料,采用统计方法与合成分析方法,对贵州冬春秋三季锋面雾的分布特征、天气形势、温湿特征与静止锋对锋面雾生消的影响进行了分析。结果表明:(1)锋面雾是出现在静止锋后的一类天气,伴有低温阴雨现象,多出现在贵州中西部(105°—108°E、25.5°—27.5°N)地区,并伴随锋面弱降水(4 mm以下)、浅薄云层(700 hPa以下)、弱逆温(3℃以下)和地面水汽饱和特征。(2)三季锋面雾出现时高空以纬向环流居多,青藏高原上短波槽活跃,低层从广西至贵州南部存在一支8~16 m·s-1偏南气流,静止锋位于贵州西部,贵州地面气温在4~14℃之间,其差异主要表现在冬季锋面雾出现时,冷空气势力最强,南支槽更活跃,静止锋梯度也最强。(3)三季静止锋变化对锋面雾生消的影响存在若干共性,即锋面雾初始时静止锋位于云贵两省之间,锋面雾出现在贵州西部相对湿度90%以上高湿区;锋面雾强盛时西部静止锋与中部辐合线之间的东南风区域是锋面雾易发区;其减弱时静止锋均出现不同程度东退北抬,雾区升温降湿作用明显。其差异在于,锋面雾初始时冬季静止锋强度和气压梯度均高于春秋两季;其强盛时冬季静止锋上气流抬升作用更明显、云水含量更充沛,锋面雾范围也较春秋两季更宽广;其减弱时春季热低压在云贵之间迅速建立,静止锋迅速东退北抬至贵州中部,而冬秋两季云贵间热低压发展强度不及春季,锋区北抬位置偏西,因而锋面雾减弱消散速度不及春季。Using the fog records from the 84 national meteorological observation stations over Guizhou from 2000 to 2013,NCEP/NCAR reanalysis data and the routine upper-air and surface observations,we have performed an analysis of the frontal fogs in winter,spring and autumn in Guizhou focusing on their basic characteristics,synoptic situation,temperature and humidity characteristics and the influence of stationary front on their generation and elimination based on statistical analysis and composited analysis methods.The main results are as follow.(1)Frontal fog is a kind of weather that appears behind the stationary front and is accompanied by low-temperature and cloudy and rainy condition,which mostly occurs in the central and western Guizhou and are followed by weak frontal precipitation below 4 mm,shallow cloud cover below 700 hPa,weak inversion of below 3℃and surface moisture saturation.(2)When the front fog appeared in different seasons,the high altitude circulation is mostly latitudinal,the short wave trough on the Tibetan-Qinghai Plateau is active,and there is an 8-16 m·s-1 southerly airflow in the low layer.The Yunnan Guizhou stationary front is in the western Guizhou,and the surface temperature in Guizhou is between 4℃and 14℃.The difference of frontal fogs in different seasons mainly show that when they appeared in winter the southwest airflow in front of southern branch trough is stronger than that in spring and autumn,and both cold air and stationary front gradient are the strongest among the three seasons.(3)There are some commonalities in the influence of stationary fronts on the formation and elimination of frontal fogs in the three seasons.That is,stationary fronts are located the junction of Yunnan and Guizhou at the beginning of fogs that appears in the high humidity area with relative humidity over 90%in the western Guizhou.During their strong phase,they are prone to appear in the southeast wind area between stationary front and convergence line.When they weaken,the stationary front moves eastward

关 键 词：锋面雾 静止锋 合成分析 相对湿度 云水含量 

分 类 号：P426.42[天文地球—大气科学及气象学]