Numerical investigations for the impacts of triple-moment and double-moment condensation schemes on the warm rain formation  

作　　者：DENG Wei SUN Ji-Ming LEI Heng-Chi 

机构地区：[1]Key Laboratory of Cloud–Precipitation Physics and Severe Storms, Institute of Atmospheric Physics [2]College of Earth Science, University of Chinese Academy of Sciences [3]Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters, Nanjing University of Information Science & Technology

出　　处：《Atmospheric and Oceanic Science Letters》2018年第6期472-480,共9页大气和海洋科学快报（英文版）

基　　金：supported by the National Basic Research Program of China(973 Program)[Grant 2014CB441403];the National Natural Science Foundation of China [Grants41275147];the National Key Research and Development Program of China [2016YFC0209000];Ningxia scientific supporting program [Grants 2015KJHM31]

摘　　要：The initiation and intensity of warm rain are processes dominated by the evolution of cloud droplet spectra.To treat the cloud condensation process properly is a fundamental step for the simulation of warm rain formation.Double-moment bulk schemes with a limited number of prognostic variables cannot simulate the evolution of droplet spectra properly.A triple-moment bulk scheme,however,should overcome the problem of spurious cloud droplet spectrum broadening induced by double-moment schemes.To compare the effects of a newly developed triplemoment scheme with double-moment schemes on warm rain formation,the authors conducted WRF-LES numerical simulations to investigate the impacts of the two types of condensation scheme on rain initiation and intensity.In the early stage of raindrop formation,the simulation with the triple-moment scheme delays the raindrop initiation and produces droplet spectra with smaller average radii than those with the double-moment scheme.In the developing stage,the triple-moment scheme reduces the raindrop water content at the precipitation center.However,the further triple-moment scheme for raindrop is needed to simulate the development of warm rain accurately.在暖云发展过程中,云滴谱的凝结不仅为对流提供能量而且直接影响暖雨的形成和发展。目前国际上广泛使用的云滴谱凝结方案主要为双参数方案,此类方案模拟的云滴谱在凝结过程中呈不正常拓宽现象,三参数云滴谱方案有效解决了该问题。为了比较两种凝结方案对暖雨初始形成和发展强度的影响,本文采用WRF模式中的理想性大涡模拟个例在相同背景条件下,分别使用两种方案模拟了一个对流热泡中暖雨的形成、发展过程。模拟结果表明:在雨滴初始形成阶段,三参数方案因为克服了双参方案中的拓宽问题,推迟了暖雨形成的时间;在暖雨发展阶段,三参数凝结方案有效削弱了暖雨区的中心强度;但在暖雨发展后期,两个凝结方案模拟结果的差异逐渐缩小。

关 键 词：Warm rain formation triple-moment bulk scheme droplet spectra 

分 类 号：P[天文地球]