Improved Diurnal Cycle of Precipitation on Land in a Global Non-Hydrostatic Model Using a Revised NSAS Deep Convective Scheme  

作　　者：Yifan ZHAO Xindong PENG Xiaohan LI Siyuan CHEN 

机构地区：[1]State Key Laboratory of Severe Weather,Chinese Academy of Meteorological Sciences,Beijing 100081,China [2]University of Chinese Academy of Sciences,Beijing 100049,China [3]CMA Earth System modeling and Prediction Centre,Beijing 100081,China [4]2035 Future Laboratory,PIESAT Information Technology Co Ltd.,Beijing 100195,China

出　　处：《Advances in Atmospheric Sciences》2024年第6期1217-1234,共18页大气科学进展（英文版）

基　　金：supported by the National Natural Science Foundation of China(Grant Nos.42375153,42075151).

摘　　要：In relatively coarse-resolution atmospheric models,cumulus parameterization helps account for the effect of subgridscale convection,which produces supplemental rainfall to the grid-scale precipitation and impacts the diurnal cycle of precipitation.In this study,the diurnal cycle of precipitation was studied using the new simplified Arakawa-Schubert scheme in a global non-hydrostatic atmospheric model,i.e.,the Yin-Yang-grid Unified Model for the Atmosphere.Two new diagnostic closures and a convective trigger function were suggested to emphasize the job of the cloud work function corresponding to the free tropospheric large-scale forcing.Numerical results of the 0.25-degree model in 3-month batched real-case simulations revealed an improvement in the diurnal precipitation variation by using a revised trigger function with an enhanced dynamical constraint on the convective initiation and a suitable threshold of the trigger.By reducing the occurrence of convection during peak solar radiation hours,the revised scheme was shown to be effective in delaying the appearance of early-afternoon rainfall peaks over most land areas and accentuating the nocturnal peaks that were wrongly concealed by the more substantial afternoon peak.In addition,the revised scheme enhanced the simulation capability of the precipitation probability density function,such as increasing the extremely low-and high-intensity precipitation events and decreasing small and moderate rainfall events,which contributed to the reduction of precipitation bias over mid-latitude and tropical land areas.

关 键 词：cumulus parameterization diurnal cycle of precipitation large-scale dynamic forcing global non-hydrostatic atmospheric model performance verification 

分 类 号：P426.6[天文地球—大气科学及气象学]