摘要
利用常规气象观测资料和降水量资料，通过大气热力学和动力学物理量场的计算，对2009年8月17日发生在河南省北部地区的一次区域性暴雨天气过程进行了分析。结果表明，副热带高压加强并西伸，中低层切变线稳定维持，冷暖空气在河南北部交汇，造成这次区域性暴雨。物理量诊断结果显示，深厚的湿层和持续的水汽辐合为暴雨的产生提供了充沛的水汽；中低层大气处于对流不稳定状态；垂直上升运动强盛；中低层辐合、高层辐散的抽吸作用有利于低层垂直上升运动的加强；中低层正涡度、中高层负涡度结构的维持，促使低层气旋性涡度环流增强，为暴雨的产生提供了动力条件，从而触发不稳定能量释放。
By using conventional meteorological observation data and precipitation data, a regional rainstorm occurred in the north of Henan province on 17 August 2009 is analyzed by calculating the physical field of atmospheric dynamics and thermodynamics. The results show that the subtropical high strengthened and extended westward. The shear line at mid-low level was continuing stable. Cold air and warm air met in the north of Henan province. These conditions resulted in regional rainstorm. The physical diagnosis results show that the deep moisture layer and the continuing water vapor convergence together offered plentiful water for the rainstorm. Atmosphere at mid-low level was in convective instability. The vertical motion was strong. The pumping action of convergence at low level and the divergence at upper was conducive to increase of vertical ascending motion. The structure of positive vorticity at low level and negative vorticity at mid-upper level was continuing stable to promote cyclonic vorticity circulation enhancement at low level and provide dynamic condition for rainstorm, thus triggered unstable energy to release.
出处
《气象与环境科学》
2010年第B09期121-125,共5页
Meteorological and Environmental Sciences
关键词
暴雨
湿位涡
散度
涡度
螺旋度
rainstorm
moist potential vorticity
divergence
vorticity
helicity
