摘要
利用NCEP再分析资料、FY-2C卫星TBB资料以及常规观测资料对2010年18日至20日的华北暴雨进行了研究。研究发现,副热带高压外围500 hPa高空槽是此次暴雨过程的直接影响系统。在此次暴雨过程中,有多个对流云团及中尺度对流系统(MCS)发生、发展并影响华北区域,MCS云团在高空西风急流转折点与副热带急流转折点及两条急流交汇点三点形成的三角形区域发生或发展,引发了这次华北暴雨到大暴雨天气。暴雨区域低层具有大的水汽辐合、大的能量场,低层能量大值区域与高层能量大值下伸区域具有较大的上升速度、大的散度,高空辐散值大于低空辐合,高空急流的动力辐散作用显著。
By using NCEP 1°× 1°reanalysis grid data, FY- 2C satellite TBB data and conventional observations, heavy rain event in north China during August 18 -20,2010 was studied. The results show that the west trough around subtropical high is the direct impact system of the heavy rainfall. In the course of the storm, a series of convective clouds and mesoscale convective systems （MCS） occur, develop and impact the north China region. MCS clouds occur in the triangle area within the two turning points of high-altitude westerly jet and subtropical jet and the point of their intersection, which induces the heavy rain in North China. Lower layer region contains high moisture and high energy. In the high energy regions of lower layer and down-stretch of the higher layer, the ascending speed is large and divergence is strong. The divergence value is greater than the convergence due to higher level jet stream.
出处
《自然灾害学报》
CSCD
北大核心
2013年第6期246-251,共6页
Journal of Natural Disasters
基金
河北省气象局科研项目(10KY26)
公益性行业科研专项(GYHY201306011)
关键词
中尺度对流系统
急流槽
动力辐散
mesoscale convective system （MCS）
jet trough
dynamic divergence
