摘要
利用新一代中尺度数值预报模式WRF和NCEP 1°×1°再分析资料,对2007年10月26日发生在沪宁高速公路区域的一次大雾天气过程进行了数值模拟,同时采用沪宁高速公路自动气象监测站的实时资料对模拟效果进行了验证,发现WRF模式较成功地模拟了此次大雾过程。结果表明:(1)此次大雾是一次典型的辐射雾,其形成主要原因之一是成雾之前的降水过程给近地层大气带来了充足的水汽,空气相对湿度达到90%以上,雾区内近地层基本上为弱的水汽辐合区;(2)弱的负涡度场有利于气流下沉,在垂直方向上可以确保湿空气不外流;(3)地面辐射冷却和低空冷平流是此次大雾形成、发展和维持的重要因素,地面辐射冷却在热力条件中起主导作用,冷平流作用远小于地面辐射冷却作用。
Using the WRF2.2,a new generation of mesoscale numerical forecasting model,and NCEP reanalysis data with 1°×1° grid,a heavy fog process appeared in the southern part of Jiangsu Province which cover the Shanghai-Nanjing Expressway on 26 October 2007 was simulated.The effect of the simulations was verified by the comparison between the simulated and observed data from the Auto-meteorological Monitoring System(AMW)(one time per minute) on the Expressway.It is found that the simulation in this fog weather process is successful.The results are as follows:(1) One of the main reasons accounted for the heavy fog event occurs a rainfall process before the fog formation.The rain bring abundant water vapor and make the maximum value of relative humidity reachs over 90% in the region.At same time,it shows that the fog region is a weak convergence zone of air stream.(2) The vorticity field with the minor and negative value is advantageous to the sinking of the air and it ensures the moist air not to spill over.(3) The cold advection and ground radiation cooling are the important factors of the engendering,developing and maintaining of this fog weather process.The ground radiation cooling is a dominant factor in the thermal conditions and the effect of cold advection is far less than the ground radiation cooling.
出处
《高原气象》
CSCD
北大核心
2011年第2期428-436,共9页
Plateau Meteorology
基金
国家科技部公益性行业专项"交通运输高影响天气预警技术研究"(GYHY200906027)资助
关键词
沪宁高速公路
辐射雾
WRF模式
数值模拟
Shanghai-Nanjing Expressway
Radiation fog
WRF model
Numerical simulation