摘要
利用2017~2019年夏、冬季天津市大气污染物监测和气象观测数据,基于天津气象铁塔垂直观测,针对大气垂直扩散条件对PM_(2.5)和O_(3)的影响进行研究.结果显示:近地面PM_(2.5)浓度随高度的升高而下降,O_(3)浓度则随高度的升高而上升,受大气垂直扩散条件的季节和日变化影响,冬季,地面与120m PM_(2.5)质量浓度相关明显,与200m PM_(2.5)质量浓度无明显相关.夏季,120m和200m PM_(2.5)质量浓度相关系数为0.72,午后通常出现120m和200m PM_(2.5)质量浓度高于地面的情况.夏季,不同高度O_(3)浓度差异小于冬季,地面与120m高度O_(3)浓度接近.以大气稳定度、逆温强度和气温递减率作为大气垂直扩散指标,对地面PM_(2.5)和O_(3)垂直分布具有指示作用.冬季,TKE与PM_(2.5)质量浓度相关系数为到-0.65,夏季,TKE与ΔPM_(2.5)相关系数为-0.39.夏、冬季TKE与地面O_(3)浓度的相关系数分别为0.46和0.53,与ΔO_(3)的相关系数分别为0.73和0.70.弱下沉运动对地面O_(3)浓度影响较强,40m高度垂直运动速度与地面O_(3)浓度的相关系数在冬、夏季分别为-0.54和-0.61.对冬季典型PM_(2.5)重污染过程的分析发现,雾霾的生消维持和PM_(2.5)浓度的变化与大气稳定度、气温垂直递减率和TKE的变化有直接关系.对夏季典型O_(3)污染过程的分析发现,近地面的O_(3)污染的形成与有利光化学反应的气象条件密切相关,同时,垂直向下输送和有利垂直扩散条件对O_(3)污染的形成和爆发影响明显.
Using the air pollutant monitoring data and meteorological observation data in summer and winter during 2017~2019 in Tianjin,the effects of atmospheric vertical diffusion conditions on PM_(2.5) and O_(3) were studied based on the vertical observation of Tianjin Meteorological Tower.The results showed that the mass concentration of near-surface PM_(2.5) decreased with height,while the concentration of O_(3) increased with height.Influenced by the seasonal and diurnal variation of atmospheric turbulence intensity,there was a significant correlation between the PM_(2.5) mass concentration on the ground and at 120m height,but insignificant correlation between the PM_(2.5) mass concentration on the ground and at 200m height in winter.In summer,the correlation coefficient of PM_(2.5) mass concentration at 120m and 200m height was 0.72 and the PM_(2.5) mass concentration at 120m and 200m height were even higher than the ground in the afternoon.In summer,the difference of O_(3) mass concentration at different heights is lower than that in winter,and the O_(3) mass concentration were close to the ground at 120m height.Atmospheric stability,temperature inversion intensity,and temperature decline rate were taken as atmospheric vertical diffusion indexes,which had certain indicator effects on the vertical gradient of PM_(2.5) and O_(3).The correlation coefficient between TKE and PM_(2.5) mass concentration was-0.65 in winter,and that between TKE andΔPM_(2.5) in summer was-0.39.The correlation coefficients between TKE and O_(3) concentration were 0.46 and 0.53,in summer and winter respectively.The correlation coefficients between TKE andΔO_(3) concentration were 0.73 and 0.70,in summer and winter respectively.The weak downdraft has an obvious influence on the increase of O_(3) concentration.The correlation coefficients between the vertical velocity at 40m height and O_(3) concentration were-0.54 and-0.61 in winter and summer,respectively.Through the analysis of a typical PM_(2.5) heavy pollution process and typical O_(3) pollution processes,it is found that the changes of atmospheric stability,temperature decline rate and TKE were closely related to the generation,extinction,maintenance and variation of PM_(2.5) pollutants.The formation of O_(3) pollution near the surface was closely related to favorable photochemical reactions.In addition,the transport influence of downdraft should also be paid attention to during O_(3) pollution processes.
作者
刘敬乐
史静
姚青
蔡子颖
韩素芹
姜明
崔晔
LIU Jing-le;SHI Jing;YAO Qing;CAI Zi-ying;HAN Su-qin;JIANG Ming;CUI Ye(Tianjin Meteorological Observation Center,Tianjin 300061;Tianjin Key Laboratory for Oceanic Meteorology,Tianjin 300074;Tianjin Environmental Meteorological Center,Tianjin 300074;Tianjin Institute of Meteorology,Tianjin 300074)
出处
《中国环境科学》
EI
CAS
CSCD
北大核心
2022年第4期1575-1584,共10页
China Environmental Science
基金
天津市自然科学基金(19JCQNJC08000)
国家自然科学基金项目(41771242)
天津市重大专项(18ZXAQSF00130,18ZXSZSF00160)。