Comparative Analysis of the Generalized Omega Equation and Generalized Vertical Motion Equation

作     者：Baofeng JIAO Lingkun RAN Na LI Ren CAI Tao QU Yushu ZHOU Baofeng JIAO;Lingkun RAN;Na LI;Ren CAI;Tao QU;Yushu ZHOU

作者机构：Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China Urumqi City Bureau of MeteorologyUrumqi 830002China 

出 版 物：《Advances in Atmospheric Sciences》 (大气科学进展（英文版）)

年 卷 期：2023年第40卷第5期

页      面：856-873页

核心收录：

学科分类：07[理学] 0706[理学-大气科学] 

基　　金：supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA17010105) National Key Research and Development Program(Grant No.2018YFC1507104) Science and Technology Development Plan Project of Jilin Province(20180201035SF) Flexible Talents Introducing Project of Xinjiang(2019) the National Key Scientific and Technological Infrastructure project“Earth System Numerical Simulation Facility”(EarthLab)。 

主　　题：generalized Omega equation generalized vertical motion equation Q vector heavy rain 

摘      要：Research on vertical motion in mesoscale systems is an extraordinarily challenging effort.Allowing for fewer assumptions,a new form of generalized vertical motion equation and a generalized Omega equation are derived in the Cartesian coordinate system(nonhydrostatic equilibrium)and the isobaric coordinate system(hydrostatic equilibrium),respectively.The terms on the right-hand side of the equations,which comprise the Q vector,are composed of three factors:dynamic,thermodynamic,and mass.A heavy rain event that occurred from 18 to 19 July 2021 in southern Xinjiang was selected to analyze the characteristics of the diagnostic variable in the generalized vertical motion equation(Qz)and the diagnostic variable in the generalized Omega equation(Qp)using high-resolution model data.The results show that the horizontal distribution of the Qz-vector divergence at 5.5 km is roughly similar to the distribution of the Qp-vector divergence at 500 hPa,and that both relate well to the composite radar reflectivity,vertical motion,and hourly accumulated precipitation.The Qz-vector divergence is more effective in indicating weak precipitation.In vertical cross sections,regions with alternating positive and negative large values that match the precipitation are mainly concentrated in the middle levels for both forms of Q vectors.The temporal evolutions of vertically integrated Qz-vector divergence and Qp-vector divergence are generally similar.Both perform better than the classical quasigeostrophic Q vector and nongeostrophic Q vector in indicating the development of the precipitation system.