贵州辐射雾的时空变化特征及其气象要素分析

Analysis of Temporal and Spatial Variation and Meteorological Elements of Guizhou Radiation Fog

选取2008—2012年贵州省3646站次的辐射雾天气过程,根据08时能见度大小将其划分为4级雾、3级雾、2级雾和1级雾四个等级,利用常规地面观测资料分析其时空变化特征,并根据辐射雾多发生区选取出修文、三穗和凤冈3个分布在贵州省高速干道上的站点,利用相应地面气象观测台站的逐日逐时实测气象要素资料,分析其不同等级的气象要素特征。结果表明:各等级辐射雾在10月—次年1月发生较多;空间分布呈"东多西少"格局,4级雾主要分布中心为修文和岑巩,其余等级辐射雾主要分布中心为三穗、凤冈、平塘、正安、松桃和锦屏;修文站的4级雾偏多与其平均相对湿度明显偏高、风速小于3 m/s和风向主要为偏东风相关性较高;三穗站和凤冈站的平均相对湿度与当日08时和前一日20时的气温差相对利于雾的生成,但其风速较小,垂直混合较弱,故其主要为较低等级雾。

According to the visibility and other observation data at 8 o＇clock from 2008 to 2012,we selected 3646 radiation fog processes and divided them into four levels based on the visibility,then analyzed their spatial and temporal variations features. We also selected three meteorological observation stations（ Xiuwen,Sansui and Fenggang） around the highway of Guizhou province where the radiation fog occur frequently,analyzed the meteorological elements features for different level of fog. The results show that： each level of radiation fog occur mostly between October and the following January,and more in the east while less in the west. The major distribution center of the 4th level fog are Xiuwen and Cengong,the distribution centers of the other levels radiation fog are Sansui,Fenggang,Pingtang,Zheng ＇an,Songtao and Jinping. The 4th level fog are more at Xiuwen station,have a significant correlation with the high average relative humidity,less than 3 m / s wind speed and the mainly east wind direction. At Sansui and Fenggang station,the average relative humidity and temperature difference between 08 on the day and 20 on the previous day are benificial to the fog formation,but the wind speed are low and vertical mixing are weak,so it is mainly lower level fog.