不同污染背景下云滴谱离散度对云降水模拟影响的个例研究  

Case Study of the Influence of Cloud Droplet Spectral Dispersion onCloud and Precipitation Simulations under Different PollutionBackgrounds

作　　者：李丹[1] 徐晓齐 贾星灿 陆春松[1] 邱玉珺[1] 邵乃夫 邹沁垚 LI Dan;XU Xiaoqi;JIA Xingcan;LU Chunsong;QIU Yujun;SHAO Naifu;ZOU Qinyao(Key Laboratory for Aerosol–Cloud–Precipitation of China Meteorological Administration,and Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters,Nanjing University of Information Science&Technology,Nanjing 210044;Nanjing Joint Institute for Atmospheric Sciences,Nanjing 210008;Key Laboratory of Transportation Meteorology,China Meteorological Administration,Nanjing 210008;Institute of Urban Meteorology,Chinese Meteorological Administration,Beijing 100089)

机构地区：[1]南京信息工程大学中国气象局气溶胶与云降水重点开放试验室/气象灾害预报预警与评估协同创新中心,南京210044 [2]南京气象科技创新研究院,南京210008 [3]中国气象局交通气象重点开放试验室,南京210041 [4]北京城市气象研究院,北京100089

出　　处：《大气科学》2023年第6期1783-1795,共13页Chinese Journal of Atmospheric Sciences

基　　金：国家自然科学基金项目41822504、42175099、42075073、41975181。

摘　　要：云滴谱离散度是云雨自动转化过程参数化中不可忽视的重要参数,对地面降水有着重要的影响。本文利用WRF-Chem(Weather Research and Forecast coupled with Chemistry)模式,对发生在2019年1月3~6日长江中下游地区的一次降水过程进行了模拟。在清洁和污染的气溶胶背景下,设定不同的云滴谱离散度的数值(0.1、0.2、0.3、0.4、0.5、0.6、0.7、0.8、0.9和1.0),研究云降水微物理的变化。结果表明,该个例降水主要来源于云雨自动转化以及云雨碰并过程。在清洁条件下的地面累计降水量大于在污染条件下的累计降水量,这是因为在清洁条件下云滴数浓度小,有利于云雨自动转化以及云雨碰并过程。虽然云雨自动转化以及云雨碰并过程占主导,但导致地面累计降水量随云滴谱离散度增大而增大的主要原因是:随着云滴谱离散度的增大,冰粒子质量浓度增大,导致融化过程增强,产生更多的雨滴,从而增强地表降水。所得结果将提高我们对云降水对气溶胶和离散度响应过程的理论认识。Cloud droplet spectral dispersion is essential to the parameterization of autoconversion,and it greatly influences surface precipitation.In this study,a model that combines the Weather Research and Forecast with chemistry(WRF-Chem)was used to simulate a precipitation process in the middle and lower reaches of the Yangtze River from January 3,2019,to January 6,2019.The microphysical changes in cloud and precipitation under clean and polluted backgrounds were studied using different values of cloud droplet spectral dispersion(0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9,and 1.0).Our results show that the precipitation mainly originates from the autoconversion of cloud droplets to rain and the accretion of cloud droplets by rain.The accumulated precipitation under the clean conditions is larger than that under the polluted conditions because the clean conditions involve a smaller concentration of cloud droplets,which is beneficial for autoconversion and accretion.Although autoconversion and accretion are dominant during precipitation processes,the accumulated precipitation increases with an increase in the cloud droplet spectral dispersion.In addition,increased cloud droplet spectral dispersion increases the mass concentration of ice particles,resulting in an enhanced melting process and,consequently,increased raindrops.This further enhances surface precipitation.Overall,our results will improve the theoretical understanding of the response of the cloud and precipitation processes to aerosol and cloud droplet spectral dispersions.

关 键 词：WRF-Chem模式 云滴谱离散度 气溶胶 云微物理过程 

分 类 号：P426[天文地球—大气科学及气象学]