Analysis on Dynamic Structure of Cold Wind Shear Heavy Rainstorm by Intensified Observational Data

With observational data from wind profiler,Doppler weather radar,surface automatic weather station(AWS) and lightning position finder,the dynamic structure of a heavy rainstorm is analyzed to search how to follow a rainstorm case by kinds of new data.This case occurred in Qingdao,the coastal city in the southeast of Shandong Province.The results are as the following.Cold wind shear is the prevailing weather system to cause the rainstorm.Cold air comes first from the lower troposphere and then cold front becomes stationary.Wind shear is obvious below 850 hPa.There are three rainfall phases.The heaviest rainfalls with strong lightning produced when cold air bursts near wind shear in 925 hPa.Rainfall was distributed in the over lapping area between northeast wind at 925 hPa and southwest wind at 850 hPa.Heavy rainfall is in accord with wind shear.Horizontal wind is obviously different during the wind shear developing. Mesoscale cyclonical circulation that is the key factor to produce convective heavy rainfall is remarka- ble at the beginning of cold air bursts.But it disappeared and is replaced by the wind shear at the forming of stationary front.In the end of stationary front,the wind shear only preserves in the mid troposphere so that stable and weak rainfall can be seen.Wind profiler data are good signal for rainstorm development. Rainfall begins with southwest wind strengthening 4 hours later and wind direction turns northeast near the surface.Strong north and south winds change by turn,which is the significant features of the heavy rain.Rain ends when wind turns north in every altitude.