摘要
利用京津塘高速公路2007年10—12月沿路自动气象站风、温、湿及能见度连续观测资料,结合气象台站地面观测及NCEP再分析资料,分析了雾过程中的大尺度环流背景及气象要素分布特征。分析表明局地路段类型雾天气主要出现在上层为下沉气流同时地面为弱气压场的环流条件下;全路段类型雾过程主要出现在对流层低层弱西风槽前的暖平流区、地面冷锋前弱气压场中。2007年10—12月各月雾发生时近地面温度范围分别为9～13℃,4～7℃和-6～1℃;近地面相对湿度一般大于90%。相对湿度为85%～90%时,也有500～1000 m低能见度天气发生。雾发生时近地面风向不定,风速一般小于2 m·s^(-1);当风速大于5 m·s^(-1)时,雾存在的概率极低。文中还给出了各路段雾生消时间、持续时段及雾天气出现次序的一般特征。
The characteristics of large-scale circulation background and meteorological elements in fog events are studied,based on the continuous observations（wind,temperature,relative humidity and visibility） at automatic weather stations along the Beijing-Tianjin-Tanggu expressway from October to December in 2007 and the NCEP re-analysis data.It is found that the typical situation of local fog exists in the circulation of downdrafts in upper air and the weak pressure field on the ground;while the systematic fog exists in the region of thermal advection in the lower troposphere and weak pressure field in front of the cold front on the ground.The air temperatures are 9-13℃,4-7℃and -6-1℃in October,November and December respectively,during fog events.And humidity is mainly over 90%but partly between 85% and 90%for the visibility of 500-1000 m,with wind direction changefully and wind speed mainly less than 2 m·s^-1.The huge differences of the formation and dissipation,duration and the sequence,occurring frequence for fogs at each section of the Beijing-Tianjin-Tanggu expressway are also obtained.
出处
《气象》
CSCD
北大核心
2010年第6期21-28,共8页
Meteorological Monthly
基金
国家自然科学基金(40775013)
天津市自然科学基金(08JCYBJC10300)
"十一五"国家科技支撑计划重点项目(2008BAC37B01
2008BAC37B05)
北京区域气象中心科技创新基金(BRMCCJ200705)资助
关键词
雾
低能见度
高速公路
气象要素
fog
low visibility
expressway
meteorological elements
