Vertical distribution of smoke aerosols over upper Indo-Gangetic Plain. (February 2020)

• Record Type: Journal Article
• Authors: Vinjamuri, K.S.; Mhawish, Alaa; Banerjee, Tirthankar; Sorek-Hamer, Meytar; Broday, David M.; Mall, Rajesh K.; Latif, Mohd Talib
• Is Part Of: Environmental pollution. Volume 257(2020)
• Publication Date: 2020-02
• Subjects: Aerosol -- Boundary layer -- CALIPSO -- Geospatial analysis -- Smoke; Pollution -- Periodicals; Pollution -- Environmental aspects -- Periodicals; Environmental Pollution -- Periodicals; Pollution -- Périodiques; Pollution -- Aspect de l'environnement -- Périodiques; Pollution -- Effets physiologiques -- Périodiques; Pollution; Pollution -- Environmental aspects; Periodicals; Electronic journals; 363.73
• DOI: 10.1016/j.envpol.2019.113377
• Languages: English
• ISSNs: 0269-7491

Abstract

Abstract: Attenuated backscatter profiles retrieved by the space borne active lidar CALIOP on-board CALIPSO satellite were used to measure the vertical distribution of smoke aerosols and to compare it against the ECMWF planetary boundary layer height (PBLH) over the smoke dominated region of Indo-Gangetic Plain (IGP), South Asia. Initially, the relative abundance of smoke aerosols was investigated considering multiple satellite retrieved aerosol optical properties. Only the upper IGP was selectively considered for CALIPSO retrieval based on prevalence of smoke aerosols. Smoke extinction was found to contribute 2–50% of the total aerosol extinction, with strong seasonal and altitudinal attributes. During winter (DJF), smoke aerosols contribute almost 50% of total aerosol extinction only near to the surface while in post-monsoon (ON) and monsoon (JJAS), relative contribution of smoke aerosols to total extinction was highest at about 8 km height. There was strong diurnal variation in smoke extinction, evident throughout the year, with frequent abundance of smoke particles at lower height (<4 km) during daytime compared to higher height during night (>4 km). Smoke injection height also varied considerably during rice (ON: 0.71 ± 0.65 km) and wheat (AM: 2.34 ± 1.34 km) residue burning period having a significant positive correlation with prevailing PBLH. Partitioning smoke AOD against PBLH into the free troposphere (FT) and boundary layer (BL) yield interesting results. BL contribute 36% (16%) of smoke AOD during daytime (nighttime) and the BL-FT distinction increased particularly at night. There was evidence that despite travelling efficiently to FT, major proportion of smoke AOD (50–80%) continue to remain close to the surface (<3 km) thereby, may have greater implications on regional climate, air quality, smoke transport and AOD-particulate modelling. Graphical abstract: Image 1 Highlights: Across South Asia, smoke aerosols were most abundant over upper Indo-Gangetic Plain. Relative abundance of smoke days' increases during October to February months. Smoke injection height was higher in wheat compared to rice residue burning period. Almost 74% of smoke AOD remain above the boundary layer height at the free troposphere. Overall, 50–80% of CALISPO smoke AOD remain close (<3 km) to the surface. Abstract : Smoke aerosols were most abundant over upper Indo-Gangetic Plain and 50–80% of smoke AOD remain close (<3 km) to the surface.