成都夏季云凝结核的变化特征及其影响因子  

Variation characteristics and influencing factors of cloud condensation nuclei over Chengdu in summer

作　　者：林欢 袁亮 刘璇 张泽中 刘佳[5,6,7] LIN Huan;YUAN Liang;LIU Xuan;ZHANG Zezhong;LIU Jia(Chengdu Plain Urban Meteorology and Environment Observation and Research Station of Sichuan Province,School of Atmospheric Sciences,Chengdu University of Information Technology,Chengdu 610225;Institute of Marine Science,Shantou University,Shantou 515063;Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration,School of Atmospheric Physics,Nanjing University of Information Science and Technology,Nanjing 210044;Chengdu Research Institute of Environmental Protection,Chengdu 610072;Research Center of Mountain Development,Institute of Mountain Hazards and Environment,Chinese Academy of Sciences,Chengdu 610041;University of Chinese Academy of Sciences,Beijing 100049;Climate Center of Sichuan Province,Chengdu/Heavy Rain and Drought-Flood Disasters in Plateau and Basin Key Laboratory of Sichuan Province,Chengdu 610072)

机构地区：[1]成都信息工程大学大气科学学院,成都平原城市气象与环境四川省野外科学观测研究站,成都610225 [2]汕头大学海洋科学研究院,汕头515063 [3]南京信息工程大学大气物理学院,中国气象局气溶胶与云降水重点开放实验室,南京210044 [4]成都市环境保护科学研究院,成都610072 [5]中国科学院、水利部成都山地灾害与环境研究所山区发展中心,成都610041 [6]中国科学院大学,北京100049 [7]四川省气候中心/高原与盆地暴雨旱涝灾害四川省重点实验室,成都610072

出　　处：《环境科学学报》2023年第5期312-324,共13页Acta Scientiae Circumstantiae

基　　金：国家自然科学基金(No.42005072);中国气象局气溶胶与云降水重点开放实验室开放基金(No.KDW1903);四川省自然科学基金项目(No.23NSFSC2327)。

摘　　要：气溶胶通过作为云凝结核(CCN)或冰核(IN)影响云和辐射,是气溶胶气候效应评估中最不确定的因素.针对四川盆地深盆地形气溶胶活化特性的研究对理解独特地形气溶胶-云相互作用具有重要意义.本文利用2020年夏季在成都地区观测的5个过饱和度(0.07%、0.10%、0.20%、0.40%和0.80%)的气溶胶活化特性资料,研究了CCN的变化特征及其影响因子.结果表明,观测期间0.40%过饱和度下CCN数浓度(NCCN(0.40%))平均值为(2392.7±1267.9)cm^(-3),远高于沿海地区、山区、干旱地区及清洁城市地区,低于污染城市区.该过饱和度下气溶胶活化率(AR(0.40%))平均为0.19±0.10,远低于污染城市区和全球平均水平.降水和新粒子生成事件(NPF)分别对NCCN的清除和增加起到重要作用.晴天NPF与较强逆温导致各过饱和度下NCCN大于阴天.低过饱和度(0.07%~0.20%)条件下晴天与阴天NCCN日变化呈双峰分布,主要与边界层发展和交通排放有关.高过饱和度(0.40%~0.80%)更有利于粒子活化的环境以及晴天与阴天不同的二次转化过程和扩散条件,导致复杂的NCCN日变化.通过N=CSk关系拟合成都地区CCN活化谱得到C=4628.5 cm^(-3)和k=0.9,表明该活化谱属于大陆型较清洁核谱.各过饱和度下AR受凝结核浓度与NCCN共同影响,日变化均呈双峰分布.AR随污染程度增强而升高的变化特征表明,该季节成都地区颗粒物污染主要由较弱的扩散条件下粒子的老化堆积导致.本研究提供了成都地区气溶胶活化特性的初步认识,扩充了四川盆地气溶胶数据库.Aerosols influence clouds and radiative forcing by acting as cloud condensation nuclei(CCN)or ice nuclei(IN),which is the most uncertain factor in estimating aerosol climate effect.Studies on aerosol activation properties is of great importance for understanding the aerosol-cloud interaction under the unique topographic conditions in the deep Sichuan Basin.The variation characteristics and influencing factors of CCN were studied by using the measurement of aerosol activation properties under 5 supersaturations(0.07%,0.10%,0.20%,0.40%和0.80%)at Chengdu in the summer,2020.The results showed that the average of CCN number concentration at the supersaturation of 0.40%(NCCN(0.40%))was(2392.7±1267.9)cm^(-3),which was higher than that in other coastal,mountains,arid,and clean urban areas,but lower than that in polluted cities.The average of aerosol activation ratio at the supersaturation of 0.40%(AR(0.40%))was 0.19±0.10,which was far lower than the polluted cities and the global mean.Precipitations and new particle formation events(NPF)played important roles in the elimination and increase of NCCN,respectively.NCCN at all supersaturations were higher on sunny days than that on cloudy days due to the NPF and inversion layer over Chengdu on sunny days.The diurnal variations of NCCN under low supersaturations(0.07~0.20)showed bimodal patterns in both sunny and cloudy days,which is attributed to the influence of the boundary layer and human activities.While the diurnal variation of NCCN under high supersaturations(0.40~0.80)were more complicated as a result of the more favorable environment for aerosol activation and the different secondary transformation processes and diffusion conditions on sunny and cloudy days.The CCN spectra fitted by N=CSk showed C=4628.5 cm^(-3) and k=0.9,indicating that the CCN spectra belonged to the clean continental type.The diurnal variation of AR under 5 supersaturations were all bimodal distributed because of the joint influences of the concentration of condensation nuclei and NCCN.The incr

关 键 词：气溶胶 云凝结核(CCN) 活化特性 成都 夏季 

分 类 号：P426[天文地球—大气科学及气象学] X16[环境科学与工程—环境科学]