Study on the Relationship Between Mesoscale Wind Field Changes and Rainstorm Using Windprofiler Data

Abstract

By using the windprofiler data,this paper studies the relationship betw een mesoscale wind field changes and rainstorm. Firstly,it is indicated that the high spatial and temporal resolution data can clearly reveal the effect of mesoscale wind filed changes such as low-level jet and low-level wind shear before the heavy precipitation happens. Before the heavy precipitation happens,the strong wind field and the momentum continuously go dow nstream,making the low-level positive vorticity increase,with the warm and humid air,trigger the precipitation. Secondly,an index I is designed to represent the intensity and height of the low-level jet,the index will increase rapidly before the heavy precipitation. Thirdly,the low-level vertical wind shear increases significantly,and it plays a significant role in triggering the generation of heavy precipitation.