摘要
利用新一代中尺度数值预报模式WRF2.2和1°×1°的NCEP气象再分析资料,对2009年9月17日发生在江苏南部地区覆盖沪宁高速公路的一次大暴雨天气过程进行了数值模拟。经AWMS(the automatic weather monitoring system)实测数据验证,此次天气过程的模拟效果较为理想。对模式输出的物理量进行诊断分析后发现:长江中下游地区的β中尺度低涡的发展、移动对暴雨过程中降水的加强和维持起着重要的作用;水汽辐合带在500hPa以下非常显著,在暴雨区形成了深厚的高湿环境,为暴雨的产生、加强和维系提供了重要的水汽条件;暴雨区内前期及降水过程中都存在较为强烈的垂直运动,且涡度场与散度场在垂直结构配置上一致,使得大气层结不稳定能量释放,形成了旺盛的对流天气;对流层中上层大气为中性层结,低层为位势不稳定,所以整层大气有对流发展,有利于暴雨的形成。
A heavy rainstorm occurring in the southern part of Jiangsu Province including Shanghai-Nanjing Expressway on September 17th,2009 is simulated by using WRF2.2（Weather Research and Forecasting Model for version 2.2） and NCEP（National Center of Environment Predicting） reanalyzed meteorological data with 1°×1° grid.The verification of the observed data from the Automatic Weather Monitoring System on the Shanghai-Nanjing Expressway displays that the results of the simulation on the rainstorm process are satisfactory and the simulations coincide with the observed values.Diagnoses are made based on the output data from the model.The results are shown as follows：（1）The development and movement of a meso-β-scale low vortex in the middle and lower reaches of the Yangtze River play an important role in the enhancement and maintenance of the rainfall in the process;（2）The moisture convergence zone below 500 hPa is significant and it provides important vapor conditions for the unstable growth of convection and the maintaining of rainstorm by the forming of the deep and humid environment in the rainfall area;（3）There is strong vertical motion in the rainfall area and the vertical structure configuration of the vorticity field is consistent with that of the divergence field.As a result,the unstable energy in the atmosphere release and the strong convective weather forms;（4）The atmospheric stratification is neutral in the middle and upper of troposphere but potential instable in the lower atmosphere.So there is convection development in the whole layer of the atmosphere,which is conducive to the formation of the rainstorm.
出处
《大气科学学报》
CSCD
北大核心
2011年第4期456-466,共11页
Transactions of Atmospheric Sciences
基金
公益性行业(气象)科研专项(GYHY(QX)200906037-27)
关键词
大暴雨
沪宁高速公路
WRF模式
诊断分析
Β中尺度低涡
heavy rainstorm
Shanghai-Nanjing expressway
WRF model
diagnostic analysis
meso-β-scale low vortex
