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Spatial distribution of aerosol black carbon over India during pre-monsoon season

Beegum, SN and Moorthy, KK and Babu, SS and Satheesh, SK and Vinoj, V and Badarinath, KVS and Safai, PD and Devara, PCS and Singh, S and Vinod, V and Dumka, UC and Pant, P (2009) Spatial distribution of aerosol black carbon over India during pre-monsoon season. Atmospheric Environment, 43 (5). pp. 1071-1078.

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Aerosol black carbon (BC) mass concentrations (BC), measured continuously during a mutli-platform field experiment, Integrated Campaign for Aerosols gases and Radiation Budget (ICARB, March-May 2006), from a network of eight observatories spread over geographically distinct environments of India, (which included five mainland stations, one highland station, and two island stations (one each in Arabian Sea and Bay of Bengal)) are examined for their spatio-temporal characteristics. During the period of study, BC showed large variations across the country, with values ranging from 27 μg m-3 over industrial/urban locations to as low as 0.065 μg m-3 over the Arabian Sea. For all mainland stations, BC remained high compared to highland as well as island stations. Among the island stations, Port Blair (PBR) had higher concentration of BC, compared to Minicoy (MCY), implying more absorbing nature of Bay of Bengal aerosols than Arabian Sea. The highland station Nainital (NTL), in the central Himalayas, showed low values of BC, comparable or even lower than that of the island station PBR, indicating the prevalence of cleaner environment over there. An examination of the changes in the mean temporal features, as the season advances from winter (December-February) to pre-monsoon (March-May), revealed that: (a) Diurnal variations were pronounced over all the mainland stations, with an afternoon low and a nighttime high; (b) At the islands, the diurnal variations, though resembled those over the mainlands, were less pronounced; and (c) In contrast to this, highland station showed an opposite pattern with an afternoon high and a late night or early morning low. The diurnal variations at all stations are mainly caused by the dynamics of local Atmospheric Boundary Layer (ABL). At the entire mainland as well as island stations (except HYD and DEL), BC showed a decreasing trend from January to May. This is attributed to the increased convective mixing and to the resulting enhanced vertical dispersal of species in the ABL. In addition, large short-period modulations were observed at DEL and HYD, which appeared to be episodic. An examination of this in the light of the MODIS-derived fire count data over India along with the back-trajectory analysis revealed that advection of BC from extensive forest fires and biomass-burning regions upwind were largely responsible for this episodic enhancement in BC at HYD and DEL.

Item Type: Article
Additional Information: Copyright of this article belongs to Elsevier.
Uncontrolled Keywords: Aerosol black carbon (BC); Arabian Sea (AS); Atmospheric boundary layer (ABL); Bay of Bengal; Black carbon; Cleaner environment; Diurnal variations; Diurnal variations (DV); Field experiments; Forest fire; Himalayas; HYSPLIT; ICARB; Mass concentrations; Monsoon season; Spatial distribution of; Temporal characteristics; Temporal features; Trajectory analysis, Aerosols; Atmospheric aerosols; Biomass; Deforestation; Fires; Modulation; Renewable energy resources; Size distribution; Troposphere, Carbon black, advection; aerosol composition; black carbon; boundary layer; concentration (composition); diurnal variation; forest fire; MODIS; radiation budget; spatial distribution; spatiotemporal analysis, Aerosols; Biomass; Carbon Black; Climates; Concentration; Curl; Deforestation; Fires; Gas; Particle Size Distribution; Renewable Resources; Seasonal Variation, Asia; Eurasia; India; South Asia
Subjects: Meteorology and Climatology
Depositing User: IITM Library
Date Deposited: 17 Feb 2015 11:08
Last Modified: 17 Feb 2015 11:08

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