Seasonal variation of atmospheric vertical extinction and its interaction with meteorological factors in the Yangtze River Delta region. (May 2020)

• Record Type: Journal Article
• Authors: Qi, Bing; Che, Huizheng; Du, Rongguang; Liang, Zhuoran; Sun, Tianze; Wang, Jizhi; Niu, Yuwen; Xu, Honghui; Hu, Deyun; Huang, Jie
• Is Part Of: Chemosphere. Volume 247(2020)
• Publication Date: 2020-05
• Subjects: Extinction coefficient -- Vertical distribution -- Meteorological factors -- Yangtze river delta region; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2019.125768
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: Based on ground-based lidar and microwave radiometer observations in Hangzhou from 1 January 2013 to 31 December 2015, the monthly characteristics of diurnal extinction as well as atmospheric boundary layer (ABL) were studied. The interactions between temperature (T), humidity fields including relative humidity (RH) and specific humidity (SH) and atmospheric stratification (AS) were analyzed to discuss the meteorological factors in the Yangtze River Delta region during the study period. The top of ABLMPL varied from 0.8 km to 1.0 km throughout in January with higher extinction intensity close to the surface combined to the largest PM2.5 about 100–120 μg/m 3 . Then the ABLMPL could develop up to 1.5 km in the spring due to the weaker extinction during the daytime. The RH in the whole column in January and December was lower than the mean value (ranging from 5% to 20%) distributed from the ground to 3 km. From May to September, the RH anomaly profiles became positive contributed to larger extinction by strengthened the particle scattering ability. In January and December, the AS was stable from the surface to 3 km coincided with the extinction distribution; while in July and August, the gradient of Δ θ se decreased which favored the diffusion of particle in the air. Moreover, April and October presented turning points in the variation of θ se . The humidity field reveals a stable condition in January and December which favored particles suppressed from the near surface to 3 km; the temperature field has tended towards a neutral state in most months except for February. The first change-point of the meteorological fields was found in April possibly attributable to the abnormal abrupt in the subtropical high. This study could have important reference for understanding regional air quality and governing air control. Graphical abstract: Image 1 Highlights: Observation of vertical aerosol extinction coefficients and meteorological factor. Interaction of ABL, atmospheric stratification and aerosol extinction. The aerosol cooling effect to the ABL in different atmospheric stratification.