贵州区域性辐射大雾特征与形成条件

通过对1971-2008年贵州省08:00能见度资料及地面天气图的普查,选取382次区域性辐射大雾天气过程,分析了贵州区域性辐射大雾的时空特征.并利用1999-2008年93次辐射雾08:00地面和高空天气图,进行天气环流条件分析；并进一步利用地面站及高空资料,研究了形成辐射雾的气象条件.研究表明,贵州区域性辐射大雾主要集中在仲秋到隆冬时段,呈现“东多西少”的分布特征,均压场是区域性辐射大雾的地面环流条件,区域性辐射大雾的四种高空环流条件为西北气流、西南气流、副热带高压、平直西风气流.地面风速小、湿度大、夜间辐射降温显著及近地层有逆温、整层“上干下湿”是形成区域性辐射雾的气象条件.

Analysis of Characteristics and Formation Conditions of Regional Radiation Fogs in Guizhou

By investigation of the visibility data at 08：00 over Guizhou Province and surface 08：00 weather charts from 1971 to 2008, a total of 382 regional radiation fog processes are selected to analyze the spatial and temporal distribution characteristics of regional radiation fogs in Guizhou. Using the surface and upper air weather charts at 08：00 of 93 radiation fog processes during the 10 years, the corresponding weather circulation conditions are researched. Using the surface and radiosonde meteorological data, the meteorological elements of influencing the formation of radiation fogs are studied. The results show that regional radiation fogs in Guizhou mainly happened in mid autumn and winter, more frequently in the east than in the west of Guizhou, and there was an evenly distributed pressure field while regional radiation fogs occurred. There are four upper air circulation conditions of regional radiation fog： northwest flow type, southwest flow type, subtropical high type and straightly west flow type. There are four meteorological conditions beneficial to the formation of regional radiation fog： low surface wind speed, high surface humidity, significant radiation cooling at night and temperature inversion at surface layer, and the vertical air with upper-layer dry and lower layer wet.