摘要
用多普勒天气雷达产品、NCEP1°×1°再分析资料、卫星云图产品、实时探测资料及MM5数值模拟,对2002年发生在湖南常德境内的"5.13"大暴雨进行解析,得出此次暴雨过程由高空低槽、中低层切变及西南急流、地面倒槽和弱冷空气共同影响产生,急流形成、发展与减弱对降水强度有直接的影响。暴雨中心与云图上的"U"形缺口区、多普勒基本速度场上的中低层急流轴线位置有较好的对应关系。多普勒基本速度场上急流强弱振荡出现的时间、低层暖平流之上(高层)出现冷平流的时间、低层气旋式涡旋流场的形成与维持以及低层垂直风切变强度变化对强降水发生的时间有明显的指示作用。数值模拟证实雷达探测到的中尺度涡旋、急流及辐合带是正确的。这些结论对暴雨临近预报业务具有明确的参考价值。
The heavy rainfall in Changde on 13 May 2002, Hunan Province in 2002 was analyzed based on Doppler weather radar products, NCEP 1°× 1° reanalysis data, satellite cloud image products, real-time detection data and MM5 numerical simulations. It is found that the rainfall event was caused by joint influences of upper-level troughs, middle-low-level shears, southwest jets, ground inverted troughs and a weak cold air. How the jet formed, developed and weakened had a direct impact on the intensity of rainfall. The rainfall center corresponded well to the ＂U＂-shaped gap of satellite cloud image and the middle-low jet axis of Doppler base velocity field. When the jet in the Doppler basic velocity field vibrated, the cold advection above the low level warm advection appeared, low-layer cyclone vortex field formed and maintained, and low-level vertical wind shear changed, it could instruct conspicuously that heavy rainfall would occur. Numerical simulation has proved the mesoscale vortex, jets and convergence to be consistent with those detected by radar. All these results have valuable reference to rainfall nowcasting.
出处
《气象》
CSCD
北大核心
2009年第5期42-48,I0004,共8页
Meteorological Monthly
基金
中国气象局新技术推广项目(CMATG2007M39)
关键词
U形缺口
暖平流
急流
中β尺度低涡
切变
暴雨
U-shaped gap warm advection jet meso-β scale vortex shear heavy rainfall
