Effects of different types of precipitation on aerosol particles in Beijing
WU Jin1,2, SUN Zhao-bin1, ZHAI Liang3, LI Chen4
1. Institute of Beijing Urban Meteorology, China Meteorlolgical Adminstration, Beijing 100081, China;
2. Beijing-Tianjin-Hebei Prediction and Early Warning Center for Environmental Meteorology, Beijing 100081, China;
3. Beijing Municipal Weather Forecast Center, Beijing 100089, China;
4. Beijing Meteorological Service Center, Beijing 100089, China
Based on the environmental and meteorological data during 2013~2015,the influence of different types of precipitation on aerosol particles was analyzed.The results showed that with the increasing rainfall precipitation,the concentration decrease ratio and mean of PM10,PM2.5,PM1 increased.PM10 declined more than PM2.5 and PM1.Different types of precipitation leaded to different effect on aerosol concentration.To the convective precipitation,atmospheric motion was fierce,which had a rapid and significant effect on scavenging of particles with different diameters.Stable rainfall was subdivided into three categories.To significant cold air type,the descending motion and wet scavenging may make particles concentration decreased slowly.To no-significant cold air and transmission type,the wet scavenging of stability weak precipitation could be neglected.To no-significant cold air and no-transmission type,rapid air humidification which made aerosol particle hygroscopic growth may lead to the concentration of particles not decreased.In snow or sleet process,with snowfall intensity increased,aerosol particle concentration decreased ratio increased.The ratio of the decrease was exponential and logarithmic.The precipitation process with snow and snow phase transition was more complicated.Besides the above factors,it was necessary to consider the influence of the change of the water droplet (snow) size caused by the change of snow phase phase,the dynamic drag action of precipitation particles on the surrounding air,the cold air subsidence movement and the change of flow situation type.
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WU Jin, SUN Zhao-bin, ZHAI Liang, LI Chen. Effects of different types of precipitation on aerosol particles in Beijing. CHINA ENVIRONMENTAL SCIENCECE, 2018, 38(3): 812-821.
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