气溶胶在重污染过程对气象和PM_(2.5)的反馈作用  

Feedback Effect of Aerosol Radiation on Meteorology and PM in Heavy Pollution Process

作　　者：孟丽红 杨旭[3] 刘丽丽 邱晓滨 李英华[1,2] 吴彬贵 MENG Lihong;YANG Xu;LIU Lili;QIU Xiaobin;LI Yinghua;WU Bingui(Tianjin Key Laboratory of Oceanic Meteorology,Tianjin 300074,China;Tianjin Institute of Meteorological Science,Tianjin 300074,China;Tianjin Environmental Meteorological Centre,Tianjin 300074,China)

机构地区：[1]天津市海洋气象重点实验室,天津300074 [2]天津市气象科学研究所,天津300074 [3]天津市环境气象中心,天津300074

出　　处：《环境科学与技术》2020年第12期63-71,共9页Environmental Science & Technology

基　　金：环渤海区域科技协同创新基金重点项目(QYXM201901);天津市气象局重点项目(202001zdxm01);天津市气象局项目(202113ybxm05);国家自然科学基金资助项目(41675018)。

摘　　要：该文利用大气环境WRF-Chem模式假设是否考虑气溶胶辐射效应2种情况,模拟2020年1月份天津地区气象场和PM_(2.5)质量浓度的演变,重点研究气溶胶辐射效应在1月15-18日天津市一次重污染过程对地面和垂直方向的温度、湿度、风速等气象要素和PM_(2.5)的反馈作用。结果表明:(1)气溶胶辐射效应使到达地面的太阳辐射大幅减少,1月份约19%的太阳辐射未到达地面,重污染过程这一比例可达到20%~35%。(2)气溶胶辐射效应与大气中PM_(2.5)浓度呈明显的正相关关系,使地面降温,风速减小,相对湿度增加,对边界层高度的降低影响尤为明显。(3)气溶胶辐射效应对天津地区气象要素的反馈作用有明显的空间分布特征,天津市区及南部静海区、大港区等区域辐射效应较为明显,而北部蓟州区基本可忽略。(4)由于边界层高度及气溶胶垂直分布类型影响,气溶胶辐射效应对近地层(450 m以下)是降温增湿作用,高层(450~2371 m)是增温减湿作用,使大气层结稳定性增强。(5)气溶胶辐射效应使近地层PM_(2.5)浓度增加,1月份地表PM_(2.5)浓度增加4.7%,重污染期间增加9.7%;气溶胶辐射效应对近地层(450 m以下)PM_(2.5)浓度是增高作用,450~1000 m是减少作用。研究显示,气溶胶辐射效应使地面降温,风速减小,相对湿度增加,对边界层高度降低尤为明显,垂直方向上先降温增湿,后增温降湿,大气层结稳定性增强,不利于污染物的扩散,为雾-霾的进一步发展和维持创造了有利条件,形成气溶胶-天气-气溶胶的循环反馈。Assuming two cases,one was aerosol radiation effect considered,the other was aerosol radiation effect not considered,the influence on the meteorology and PM_(2.5)quality in January 1-312020 in Tianjin was simulated using WRF-Chem.A heavy pollution process in Tianjin on January 15-18 was mainly studied.Comparison of modeling results in the presence and absence of aerosol feedback during January 1-31 shows that aerosols lead to a significant negative radiation forcing of 19%at the surface,and the proportion of heavy pollution process can reach 20%~35%.The aerosol radiation effect has an obvious positive correlation with the concentration of PM_(2.5),which decreases the temperature,the wind speed,increases the relative humidity on the surface,and the influence on the decreases of the boundary layer height is particularly obvious.The aerosol radiation effect has obvious spatial distribution characteristics in Tianjin.The aerosol radiation effect is obvious on the urban and south of Tianjin Jinghai and Dagang District,while the Jizhou District in the north of Tianjin could be ignored.Due to the influence of the height of the boundary layer and the vertical distribution of aerosols,the effect of aerosol radiation(below 450 m)decreases the temperature and increases relative humidity,and on the upper layer(450~2371 m)the effect decreases temperature and increases relative humidity,which makes the stability of atmospheric stratification enhanced.The aerosol radiation effect increases the surface PM_(2.5)by 4.7%in January,and 9.7%during heavy pollution.The aerosol radiation effect increases PM_(2.5)near the ground(below 450 m),and decreases PM_(2.5)at 450~1000 m.The results show that the aerosol radiation effect decreases the temperature,wind speed,increases the relative humidity on the surface,and especially for the boundary layer height decreasing.In the vertical direction,the temperature decreases first and then increases,while the relative humidity increases first and then decreases.The stability of atmospheric stratif

关 键 词：WRF/Chem 气溶胶辐射效应 反馈作用 大气边界层 

分 类 号：X513[环境科学与工程—环境工程]