Aerosol characteristics in north-east India using ARFINET spectral optical depth measurements

Pathak, Binita; Subba, Tamanna; Dahutia, Papori; Bhuyan, Pradip Kumar; Moorthy, K. Krishna; Gogoi, Mukunda M.; Babu, S. Suresh; Chutia, Lakhima; Ajay, P.; Biswas, Jhuma; Bharali, Chandrakala; Borgohain, Arup; Dhar, Pranab Kumar; Guha, Anirban; De, B. K.; Banik, Trisanu; Chakraborty, Monti; Kundu, Shyam Sundar; Sudhakar, S.; Singh, Shiva Kumar

doi:10.1016/j.atmosenv.2015.07.038

Cited by 50 publications

(46 citation statements)

References 49 publications

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“…Significant contribution of absorbing aerosols to lower atmospheric warming over different parts of NE region of India has also been reported by Gogoi et al [62]. Pathak et al [63] have reported that atmospheric forcing due to composite aerosols over Imphal (a valley location south of DMD in NE region of India) was 25. . The global mean clear-sky ARF at the TOA and the surface are however found to be negative [64].…”

Section: Aerosol Radiative Forcingmentioning

confidence: 83%

Spatial Variability and Radiative Impact of Aerosol along the Brahmaputra River Valley in India: Results from a Campaign

Kundu¹,

Borgohain²,

Barman³

et al. 2018

JEP

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The first ever land campaign to study the spatial variability of the aerosol characteristics along the Brahmaputra river valley (BRV) in Assam, North-Eastern India, was conducted during 2011. Measurements were made over 13 locations for Aerosol Optical Depth (AOD), scattering coefficient, particulate matter, black carbon (BC) concentration and meteorological parameters. The BRV is divided into three sectors longitudinally viz western sector (WS), central sector (CS), and eastern sector (ES). Significant Spatial heterogeneity in AOD and BC concentration was observed (p < 0.05) with the highest values over WS and a continual decrease from WS to ES with aerosol dominance in PM2.5 category along the entire valley. The Angstrom coefficient measured using different wavelength pairs showed spatial variability indicating dominance of fine particles over WS and coarse particles in ES with a probable bimodal distribution. The scattering and absorption coefficient shows dominance of both types of aerosol over WS than other areas. The shortwave radiative forcing was higher over the WS than CS and ES of the valley. The campaign revealed that under favorable wind conditions, the BRV is loaded with significant amount of natural and anthropogenic aerosol during local winter and is influenced by the long-range transport of aerosols from the Indo-Gangetic plain.

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Section: Aerosol Radiative Forcingmentioning

confidence: 83%

Spatial Variability and Radiative Impact of Aerosol along the Brahmaputra River Valley in India: Results from a Campaign

Kundu¹,

Borgohain²,

Barman³

et al. 2018

JEP

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“…[] and Pathak et al . [] have also reported the peaking of columnar AOD in the premonsoon month March from the study of long‐term columnar aerosol optical depth properties over Dibrugarh. This provides a clear indication of possible elevated layers of absorbing aerosols, most probably above the atmospheric boundary layer, during the premonsoon season when the near‐surface BC concentrations are reduced from their peak values in winter.…”

Section: Resultsmentioning

confidence: 99%

“…Locally, the region is rich in its large extent of green tea gardens and forest covers in most of its part and devoid of major anthropogenic and industrial sources. However, the emission of carbonaceous aerosols from the scattered brick kilns and oil wells provide local contribution to the absorbing aerosol concentrations over this region [ Gogoi et al ., ; Pathak et al ., ]. The major emissions from oil and gas exploration are due to the flaring, venting, and purging of gases (including black smoke emissions); combustion of diesel engines; operation of fire protection systems; road traffic; and fugitive gas losses.…”

Section: Introductionmentioning

confidence: 99%

Radiative effects of absorbing aerosols over northeastern India: Observations and model simulations

et al. 2017

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Multiyear measurements of spectral properties of aerosol absorption are examined over four geographically distinct locations of northeastern India. Results indicated significant spatiotemporal variation in aerosol absorption coefficients (σabs) with highest values in winter and lowest in monsoon. The western parts of the region, close to the outflow of Indo‐Gangetic Plains, showed higher values of σabs and black carbon (BC) concentration—mostly associated with fossil fuel combustion. But, the eastern parts showed higher contributions from biomass‐burning aerosols, as much as 20–25% to the total aerosol absorption, conspicuously during premonsoon season. This is attributed to a large number of burning activities over the Southeast Asian region, as depicted from Moderate Resolution Imaging Spectroradiometer fire count maps, whose spatial extent and magnitude peaks during March/April. The nearly consistent high values of aerosol index (AI) and layer height from Ozone Monitoring Instrument indicate the presence of absorbing aerosols in the upper atmosphere. The observed seasonality has been captured fairly well by Goddard Chemistry Aerosol Radiation and Transport (GOCART) as well as Weather Research and Forecasting–Chemistry (WRF‐Chem) model simulations. The ratio of column‐integrated optical depths due to particulate organic matter and BC from GOCART showed good coincidence with satellite‐based observations, indicating the increased vertical dispersion of absorbing aerosols, probably by the additional local convection due to higher fire radiative power caused by the intense biomass‐burning activities. In the WRF‐Chem though underperformed by different magnitude in winter, the values are closer or overestimated near the burnt areas. Atmospheric forcing due to BC was highest (~30 Wm−2) over the western part associated with the fossil fuel combustion.

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“…They have shown the spatial distinctiveness and the seasonality of aerosol types (anthropogenic, dust and sea-salt) over the different parts of Indian mainland and delineated the importance of long-range transport (especially of mineral dust from the Middle East, eastern Africa and West Asian deserts, and of sea-salt from the Arabian Sea and Indian Ocean). Syntheses at sub-regional scales have established and quantified, to a certain extent, the significant impacts of convective mixing and associated meso-scale dynamics of the local boundary layer and local human activities; all modulated by synoptic meteorology, biomass burning and urban activities in producing the observed spatiality and seasonality 45,48,51,79,85,107,108,[122][123][124][125] .…”

Section: Spatial Synthesis Observations and Modelsmentioning

confidence: 99%

Evolution of Aerosol Research in India and the RAWEX–GVAX:An Overview

2016

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Climate change has great significance in Asia in general, and India in particular; and atmospheric aerosols have a decisive role in this. The climate forcing potential of aerosols is closely linked to their optical, microphysical and chemical properties. Systematic efforts to characterize these properties over the Indian region started about 5 decades ago, and evolved over the years through concerted efforts in the form of long-term scientific programmes as well as concerted fields experiments. All these have resulted in this activity becoming one of the most vibrant fields of climate research in India and have brought several important issues in the national and international foci. The field experiment, RAWEX-GVAX (Regional Aerosol Warming Experiment-Ganges Valley Aerosol Experiment), conducted during 2011-12 jointly by the US Department of Energy, Indian Space ResearchOrganization and Department of Science and Technology, has emerged as a direct outcome of the above efforts. This overview provides a comprehensive account of the development of aerosol-climate research in India and south Asia, and the accomplishment and newer issues that warranted the above field campaign. Details of RAWEX-GVAX, the major outcomes and the subsequent and more recent efforts are presented, followed by the way forward in this field for the next several years to come.

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Aerosol characteristics in north-east India using ARFINET spectral optical depth measurements

Cited by 50 publications

References 49 publications

Spatial Variability and Radiative Impact of Aerosol along the Brahmaputra River Valley in India: Results from a Campaign

Spatial Variability and Radiative Impact of Aerosol along the Brahmaputra River Valley in India: Results from a Campaign

Radiative effects of absorbing aerosols over northeastern India: Observations and model simulations

Evolution of Aerosol Research in India and the RAWEX–GVAX:An Overview

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