Performance of a Global Spectral Model with Dry Air-Mass and Total Air-Mass Conserving Dynamical Cores:A Case Study of the July 2021 Henan Extreme Rainfall Event

作     者：Xiangrong YANG Weimin ZHANG Jun PENG Shaoying LI Jianping WU Xiangrong YANG;Weimin ZHANG;Jun PENG;Shaoying LI;Jianping WU

作者机构：College of Meteorology and OceanographyNational University of Defense TechnologyChangsha 410600 

出 版 物：《Journal of Meteorological Research》 (气象学报（英文版）)

年 卷 期：2023年第37卷第1期

页      面：20-44页

核心收录：

学科分类：07[理学] 070601[理学-气象学] 0706[理学-大气科学] 

基　　金：Supported by the National Natural Science Foundation of China(41875121 42205163 and 42275062) 

主　　题：dry(total)air-mass conservation water source(sink) “21.7”Henan extreme rainfall global model 

摘      要：This study investigates the effects of the assumption on the types of air-mass conservation prescribed in numerical ***,predictions of the July 2021(“21.7)Henan extreme rainfall event from the Integrated Forecast System(IFS)at ECMWF were compared with those from the Yin-He Global Spectral Model(YHGSM),which is a global spectral model with total air-mass conservation(TMC)and dry air-mass conservation(DMC)***,a sensitivity test between simulations from the YHGSM adopting TMC and DMC was *** results show that both the IFS and YHGSM predicted relatively well the 24-h rainfall amount less than 100 mm day−1 on 20 and 21 July 2021 at lead times of 84,60,and 36 *** heavy precipitation exceeding 100 mm day−1,however,both models obviously underestimated the daily rainfall amount on 20 July 2021,but the YHGSM produced more precise and stable precipitation forecasts on these two days than the IFS,especially the maximum 24-h precipitation amount,with better consistency at lead times of 84,60,and 36 *** differences are further examined in the sensitivity *** from the YHGSM with DMC show rainfall distributions and daily rainfall amounts closer to the observations at longer lead *** is inferred that considering sources or sinks of total water in dynamical cores with DMC may have positive feedback for the precise prediction of *** extreme rainfall events,the high local loss of total water may have caused a loss of the atmospheric mass,leading to an additional decrease in surface ***,the unbalanced pressure gradient force enhances the cyclonic rotation of surface wind and strengthens convergence in the lower troposphere,which in turn further strengthens the vertical velocity,circularly contributing to the enhanced precipitation if the water vapor condition is favorable.