Characteristics Analysis of 3-dimensional Wind Structure of a Heavy Rainfall Event in Southern Fujian Using Dual-radar Retrieval

Zhang Wei; Luo Changrong; Zheng Hui

doi:10.16765/j.cnki.1673-7148.2017.04.011

Abstract：Pre-flood rainstorm is one of the most common disasters in Southern China and is very difficult to predict.Thc most direct influence system is mesoscale convective system (MCS).Using regional auto weather station data,NCEP reanalysis data,Doppler weather radar (CINRAD/SA) base data in Xiamen,Quanzhou,the 3 dimensional wind structure of heavy rainfall event on 20 May 2015 in southern Fujian is studied by means of dual-Doppler radar wind retrieval in terrestrial coordination system.The result shows that this heavy rainfall is induced by low level wind-shear along the coast area of southern Fujian due to convergence of warm and cold air.Wind retrieval method can clearly show the moving process of the low level wind-shear along with the 3 dimensional wind structure of convective cells in different life stages.Strong echo region moves south along with the wind-shear and is distributed in both sides of the shear line.While the shear line passing through and wind direction is uniform,the further development of strong echos is inhibited and rainstorm begins to weaken.For convective cells,if there is low level convergence and uniform vertical upward motion,it is in developing stage and could reinforce.If there is uniform vertical downward motion and no obvious inflow,it is in subsiding stage.The mcthod of "dual-Doppler radar wind retrieval in dynamic terrestrial coordination system",in comparison with conventional methods,realizes quantitative application of radar radial data,could reveal the 3 dimensional wind structure of MCS more intuitive,and by calculating and displaying vertical velocity,could estimate the further evolution of echo quickly and has positive reference significance for the rapid prediction of echo intensity evolution.