Application of Gaussian Weight to Improve Perturbation Features of Convection-Permitting Ensemble Forecast Based on Local Breeding of Growing Modes  

作　　者：Kun LI Chaohui CHEN Hongrang HE Ru YANG Yi LI Yongqiang JIANG 

机构地区：[1]College of Meteorology and Oceanography,National University of Defense Technology,Changsha 410073 [2]PLA Troop 95112,Foshan 528000

出　　处：《Journal of Meteorological Research》2021年第3期490-504,共15页气象学报（英文版）

基　　金：Supported by the National Key Research and Development Program of China(2017YFC1501803);National Natural Science Foundation of China(41975128 and 41875060)。

摘　　要：Local breeding of growing modes(LBGM)is a method used to generate initial condition perturbation(ICP)for convection-permitting ensemble forecasts.Equal weights(EWs)are usually presumed in LBGM during the localization of ICP,without considering different contributions of the grid points within the local radius.To address this problem,Gaussian weights(GWs)are proposed in this study,which can accommodate the varied influences of the grids inside the local radius on the central grid through a Gaussian function.Specifically,two convection-permitting ensemble forecast experiments based on LBGM with GWs and EWs are compared and analyzed respectively for two squall line cases.The results showed that the use of the GWs intensified the local characteristics of the ICP and made the distribution of the ICP fields more flow-dependent.Kinetic energy spectrum of the ICP indicated that there could be more large-scale information in the ICP by using the GWs.In addition,mesoscale information also improved slightly.For forecast of nonprecipitation variables,GWs improved the relationship between the root-mean-square error and the spread and contributed to the forecasting accuracy of wind,temperature,geopotential height,and humidity.For the precipitation forecast,GWs simulated the precipitation structure successfully and provided better probability forecasting during the evolution of the two squall line processes than the EWs.

关 键 词：local breeding of growing modes(LBGM) convection-permitting ensemble Gaussian weight(GW) initial condition perturbation(ICP) 

分 类 号：P456.7[天文地球—大气科学及气象学]