大气科学2025，Vol.49Issue(2)：297-312,16.DOI:10.3878/j.issn.1006-9895.2309.23040
新疆天山地区夏季大气气溶胶粒径分布和云凝结核活化特征
Characteristics of Aerosol Particle Size Distribution and Cloud Condensation Nuclei Activation during Summer in the Tianshan Mountains in Xinjiang
摘要
Abstract
To investigate the characteristics of CCN(cloud condensation nuclei)and aerosol particle size distribution,along with their influencing factors in the Middle Tianshan region of Xinjiang,data on aerosol and CCN number concentration were collected from 4 to 25 August 2019.Measurements were conducted using an aerosol wide-range particle size spectrometer and a CCN counter,complemented by meteorological data and the HYSPLIT model for comprehensive analysis.The results revealed that during the observation period,the average aerosol number concentration in Tianshan was 3607±4105 cm-3,with Aitken mode particles accounting for the highest proportion(64.76%).The mean CCN number concentrations at supersaturation levels of 0.1%,0.2%,0.4%,0.6%,and 0.8%were 185±185 cm-3,648±345 cm-3,1576±1045 cm-3,2077±1417 cm-3,and 2408±1657 cm-3,respectively.The average aerosol number concentration exhibited a unimodal distribution,with the peak particle size located at 29.5 nm.Diurnal variations in aerosol number concentration showed peaks at 0800 BJT(Beijing time),1700 BJT,and 2000 BJT,influenced primarily by the boundary layer height diurnal variation,mountain-valley winds,emission sources,and other factors.During summer,aerosol particles in the Tianshan Mountains exhibited distinct distribution modes.The Aitken mode particles exhibited a bimodal distribution,while the accumulation mode particles displayed a trimodal distribution.The number concentration of nucleation mode particles showed an unimodal diurnal variation,likely attributable to NPF(new particle formation).The CCN activation spectrum fitting yielded N=3111S0.896(where N is the CCN number concentration at supersaturation S),characteristic of a clean continental type.The diurnal variation of CCN number concentration peaked at 0800 BJT,1800 BJT,and 2100 BJT.NPF was found to enhance the CCN number concentration in the Tianshan Mountains.At supersaturation levels of 0.1%,0.2%,0.4%,0.6%,and 0.8%,the average CCN concentrations on NPF days were respectively 13%,18%,25%,22%,and 20%higher than those on non-NPF days.RH(relative humidity)had a more significant impact on the concentration of nucleation mode particles compared with other particle modes.As RH increased,the aerosol size distribution shifted toward larger particle sizes.When RH exceeded 60%,the number of concentrations of both aerosols and CCN decreased with increasing RH.Additionally,aerosol and CCN number concentrations were higher under northerly and easterly winds,influenced by the region's topography and valley wind patterns.The Tianshan region experienced four main types of air masses:western(29.2%),northwestern(29.3%),northeastern(27.0%),and southern(14.5%).The northeastern air mass originating from the northern Tianshan Mountains exhibited the highest aerosol number concentration at 5449±3793 cm-3,while the southern air mass had the lowest at 1971±2087 cm-3.These differences are attributed to variations in air mass direction,movement paths,and the influence of the northern urban zone.At all supersaturation levels,the northeastern air mass also showed higher CCN number concentrations(which ranged from 100%to 150%)than the southern air mass.关键词
天山/气溶胶/云凝结核/气象要素/新粒子生成事件/不同主导气团Key words
Tianshan/Aerosol/Cloud condensation nuclei/Meteorological elements/New particle formation/Different dominant air mass分类
大气科学引用本文复制引用
武自豪,景晓琴,杨军,陈倩,刘思晗,可玥,刘安康,王红磊,银燕,甄钟秀,陈魁,杨璟,李圆圆,李斌..新疆天山地区夏季大气气溶胶粒径分布和云凝结核活化特征[J].大气科学,2025,49(2):297-312,16.基金项目
西北人工影响天气项目ZQCR18211,中国气象局西北区域人影建设研究试验项目RYSY201902 Funded by Weather Modification Ability Construction Project of Northwest China(Grant ZQCR18211),Weather Modification Construction Research and Test Project in Northwest China of China Meteorological Administration(Grant RYSY201902) （Grant ZQCR18211）
