Analysis of Pressure Forcings for the Vertical Turbulent Fluxes in the Convective Boundary Layer at Gray Zone Resolutions

作     者：Yahua WANG Xiaoping CHENG Jianfang FEI Bowen ZHOU Yahua WANG;Xiaoping CHENG;Jianfang FEI;Bowen ZHOU

作者机构：College of Meteorology and OceanographyNational University of Defense TechnologyChangsha410005China Key Laboratory of Electro-Optical Countermeasures Test and Evaluation TechnologyLuoyang471000China Key Laboratory for Mesoscale Severe WeatherMinistry of EducationSchool of Atmospheric SciencesNanjing UniversityNanjing210000China 

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

年 卷 期：2023年第37卷第6期

页      面：841-854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 Joint Funds of the National Natural Science Foundation of China (U2142209) Major Program of the National Natural Science Foundation of China (42192552) 

主　　题：convective boundary layer gray zone flux budget pressure covariance turbulence parameterization 

摘      要：At kilometer and sub-kilometer resolutions,known as the numerical gray zone for boundary layer turbulence,the atmospheric boundary layer turbulence becomes partially resolved and partially subgrid-scale(SGS) in a numerical model,thus requiring scale-adaptive turbulence *** schemes are often built by modifying the existing parameterizations,either the planetary boundary layer(PBL) schemes or the large-eddy simulation(LES) closures,to produce the right SGS turbulent fluxes at gray zone ***,the underlying forcings responsible for the changes in the vertical turbulent fluxes are largely ignored in these *** study follows the original approach of Wyngaard(2004) and analyzes the turbulent buoyancy and momentum flux budgets,to gain a better understanding of the variations of flux forcings at gray zone *** investigation focuses on the pressure covariance term,which is one of the most dominant terms in the budget *** using the coarse-grained LES of a dry convective boundary layer(CBL) case as reference,two widely-used pressure covariance models are evaluated and optimized across the gray zone resolution *** optimized linear model is further evaluated a priori against another dry CBL case with a different bulk stability,and a shallow-cumulus-topped boundary layer *** model applies well to both cases,and notably shows good performance for the cloud *** on the analysis of the flux forcings and the optimized pressure model,a scale-adaptive turbulence model for the gray zone is derived from the steady-state flux budgets.