Variability of turbulence dispersion characteristics during heavy haze process: A case study in Beijing

作     者：Lei Liu Yu Shi Zhe Zhang Fei Hu 

作者机构：LAPCInstitute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China University of Chinese Academy of SciencesBeijing 100049China 

出 版 物：《Journal of Environmental Sciences》 (环境科学学报（英文版）)

年 卷 期：2023年第124卷第2期

页      面：440-450页

核心收录：

学科分类：07[理学] 070602[理学-大气物理学与大气环境] 0706[理学-大气科学] 0714[理学-统计学（可授理学、经济学学位）] 0701[理学-数学] 

基　　金：supported by the National Natural Science Foundation of China (No.41975018) the General Financial Grant from the China Postdoctoral Science Foundation (No.2020M670420) 

主　　题：Heavy haze Turbulence dispersion Local similarity Lagrangian model 

摘      要：The turbulent standard deviations and the turbulent third-order and fourth-order moments are the key turbulence dispersion parameters in Lagrangian dispersion models.However,the characteristics of these parameters under heavy haze conditions in urban areas have not been fully investigated,and the commonly used similarity relations of these parameters in modelswere based on observations in highly flat and sparsely populated areas.In this paper,the vertical profiles of these parameters and their local similarity relations under heavy haze conditions in the wintertime of Beijing have been analyzed by using data collected at a 325-m meteorological tower.The heavy haze process has been divided into three stages:transport stage(TS),cumulative stage(CS),and dispersion stage(DS).Results show that the turbulent dispersion parameters behave differently during three stages.In the TS and DS,the maxima appear in the profiles of the turbulent standard deviations above the urban canopy;in the CS,the turbulent standard deviation are almost constant with height.The analysis of the third and fourth order moments shows that the wind velocities above the urban canopy in the TS deviate from the Gaussian distribution more significantly than those in the CS and DS.The local similarity relations of the turbulent dispersion parameters in the TS,especially for the longitudinal wind components,are normally different from those in the CS and DS.Thus,different from the common assumptions in Lagrangian models,the turbulence dispersion in horizontal directions is anisotropic and should be parameterized by multiple similarity relations under heavy haze conditions.