从夹卷的角度探讨雾不同阶段微物理量的变化机理  

Examination of Mechanisms Underlying the Variations of Microphysical Properties in Different Fog Phases from the Perspective of Entrainment

作　　者：吴诗晓 陆春松[1] 朱磊[1] 高思楠 吕晶晶[1] WU Shixiao;LU Chunsong;ZHU Lei;GAO Sinan;LV Jingjing(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)

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实验室/气象灾害预报预警与评估协同创新中心,南京210044

出　　处：《大气科学》2021年第5期1057-1070,共14页Chinese Journal of Atmospheric Sciences

基　　金：国家重点研发计划项目2019YFA0606803;国家自然科学基金项目41822504、41975181、41675136、41875170、42175099。

摘　　要：夹卷混合过程作为影响云雾的主要物理过程之一,对云雾的生命周期、云雾降水的形成过程、辐射传输过程和气溶胶间接效应等都有着重要影响。本文从微物理和动力两个方面探讨辐射雾中的夹卷混合机制,既促进对夹卷混合机制的理论认识,又从新的角度来讨论辐射雾的发展消亡过程。利用2006年和2007年冬季在南京进行的雾综合观测的资料,研究了9个个例中的夹卷混合机制。首先,针对2007年12月10~11日这一次辐射雾过程进行详细分析,探讨了不同阶段微物理量的变化和夹卷混合机制。结果表明:成熟阶段主要为极端非均匀夹卷混合机制,数浓度和含水量同时减小,体积平均半径却基本保持不变;快速消散阶段主要为均匀夹卷混合机制,各微物理量同时减小,互为正相关关系。除了微物理,本文也分析了夹卷混合机制的动力特征,计算了过渡尺度数,发现在成熟(快速消散)阶段,过渡尺度数小(大),有利于极端非均匀(均匀)夹卷混合机制的发生。其次,分析了其他8个个例中微物理量之间的相关关系,发现体积平均半径和含水量之间主要呈正相关关系,以均匀夹卷混合为主。所得结果有助于夹卷混合机制参数化方案的开发,同时为辐射雾的模拟预报提供参考。As one of the main processes affecting cloud and fog,the entrainment-mixing process has an important impact on the cloud/fog life cycle,precipitation formation,radiative transfer,aerosol indirect effect evaluation,and so on.This study discussed the entrainment-mixing mechanisms in a radiation fog from the microphysical and dynamical perspectives,which not only improved the theoretical understanding of entrainment-mixing mechanisms but also revealed the development and dissipation of radiation fog from a new perspective.Using the comprehensive field observational data in Nanjing during the 2006 and 2007 winter,entrainment-mixing mechanisms in nine fog cases were analyzed.First,a radiation fog event during December 10-11,2007,was studied to understand the microphysical relationships and entrainment-mixing mechanisms during different phases in detail.Results showed that the extreme inhomogeneous entrainment-mixing was found in the mature phase,in which the volume-mean radius slightly changed as the number concentration and liquid water content decreased.The homogeneous entrainment-mixing was found in the rapid dissipation phase,in which all microphysical properties decreased simultaneously with positive correlations.Except for microphysical properties,the scale number was calculated as a dynamical measure for entrainment-mixing mechanisms.In the mature(rapid dissipation)phase,the scale number was small(large),indicating that the extreme inhomogeneous(homogeneous)entrainment-mixing was most likely to occur.The microphysical relationships of the other eight fog events were then examined,which indicated that the volume-mean radius had positive correlations with the liquid water content in general,i.e.,homogeneous entrainment-mixing dominated.The research results were helpful to the development of parameterization schemes of entrainment-mixing mechanisms and provided a reference for the simulation and prediction of radiation fog.

关 键 词：夹卷混合 辐射雾 微物理关系 南京 

分 类 号：P426[天文地球—大气科学及气象学]