Dust events in Kanpur, northern India: Chemical evidence for source and implications to radiative forcing

Chinnam, N.; Dey, Sagnik; Tripathi, Sachchida Nand; Sharma, Manoj Kumar

doi:10.1029/2005gl025278

Cited by 118 publications

(102 citation statements)

References 13 publications

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“…Such a coexistence of mineral dust and high pollution levels in Beijing is confirmed by the yearly particle analysis of Zheng et al (2005). Similar conditions are also reported for Kanpur by Chinnam et al (2006). Alta Floresta, a site characterized by high biomass burning, provides a nice example of cloud contamination: the whole dataset shows a very coherent fine mode of 0.10-0.13 µm with concurrent increase in AOT and coarse mode fraction taking place exactly along the constant R f curves.…”

Section: Application To Aeronet Datasupporting

confidence: 79%

Classification of aerosol properties derived from AERONET direct sun data

Gobbi

Kaufman²,

Koren³

et al. 2007

Atmos. Chem. Phys.

225

218

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Abstract. Aerosol spectral measurements by sunphotometers can be characterized by three independent pieces of information: 1) the optical thickness (AOT), a measure of the column aerosol concentration, 2) the optical thickness average spectral dependence, given by the Angstrom exponent (α), and 3) the spectral curvature of α (δα). We propose a simple graphical method to visually convert (α, δα) to the contribution of fine aerosol to the AOT and the size of the fine aerosols. This information can be used to track mixtures of pollution aerosol with dust, to distinguish aerosol growth from cloud contamination and to observe aerosol humidification. The graphical method is applied to the analysis of yearly records at 8 sites in 3 continents, characterized by different levels of pollution, biomass burning and mineral dust concentrations. Results depict the dominance of fine mode aerosols in driving the AOT at polluted sites. In stable meteorological conditions, we see an increase in the size of the fine aerosol as the pollution stagnates and increases in optical thickness. Coexistence of coarse and fine particles is evidenced at the polluted sites downwind of arid regions.

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Section: Application To Aeronet Datasupporting

confidence: 79%

Classification of aerosol properties derived from AERONET direct sun data

Gobbi

Kaufman²,

Koren³

et al. 2007

Atmos. Chem. Phys.

225

218

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“…Ho et al (2007) have observed significantly lower oxalic acid concentrations for the summer season as compared to winter in a study conducted over 14 Chinese cities. Over the northern part of Indian subcontinent high dust loading rich in mineral aerosols (especially iron content) has been reported during the summer season (Chinnam et al, 2006 and references therein). also reported a similar depletion of oxalic acid relative to other diacids in Arctic aerosols during the polar sunrise (spring season).…”

Section: Concentrations Of Total Diacids Overmentioning

confidence: 99%

Seasonal variations of water-soluble organic carbon, dicarboxylic acids, ketocarboxylic acids, and α-dicarbonyls in Central Himalayan aerosols

Hegde

Kawamura

2012

Atmos. Chem. Phys.

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Abstract. Aerosol samples were collected from a high elevation mountain site (Nainital, India; 1958 m a.s.l.) in the central Himalayas, a location that provides an isolated platform above the planetary boundary layer to better understand the composition of the remote continental troposphere. The samples were analyzed for water-soluble dicarboxylic acids (C 2 -C 12 ) and related compounds (ketocarboxylic acids and α-dicarbonyls), as well as organic carbon, elemental carbon and water soluble organic carbon. The contributions of total dicarboxylic acids to total aerosol carbon during wintertime were 1.7 % and 1.8 %, for day and night, respectively whereas they were significantly smaller during summer. Molecular distributions of diacids revealed that oxalic (C 2 ) acid was the most abundant species followed by succinic (C 4 ) and malonic (C 3 ) acids. The average concentrations of total diacids (433±108 ng m −3 ), ketoacids (48±23 ng m −3 ), and α-dicarbonyls (9±4 ng m −3 ) were similar to those from large Asian cities such as Tokyo, Beijing and Hong Kong. During summer most of the organic species were several times more abundant than in winter. Phthalic acid, which originates from oxidation of polycyclic aromatic hydrocarbons such as naphthalene, was found to be 7 times higher in summer than winter. This feature has not been reported before in atmospheric aerosols. Based on molecular distributions and air mass backward trajectories, we conclude that dicarboxylic acids and related compounds in Himalayan aerosols are derived from anthropogenic activities in the highly populated Indo-Gangetic plain areas.

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“…In the Indian sub-continent, a positive aerosol forcing has been reported by several authors, e.g., at Kanpur in the Indo-Gangetic (IG) basin (Chinnam et al, 2006, Dey andTripathi, 2008), in the wintertime at Manora Peak in the Published by Copernicus Publications on behalf of the European Geosciences Union. 11210 G. P. Gobbi et al: Sunphotometry 2006 at the Himalayan EvK2-CNR station (5079 m a.s.l.)…”

Section: Introductionmentioning

confidence: 98%

Sunphotometry of the 2006–2007 aerosol optical/radiative properties at the Himalayan Nepal Climate Observatory-Pyramid (5079 m a.s.l.)

et al. 2010

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Abstract. In spite of being located at the heart of the highest mountain range in the world, the Himalayan Nepal Climate Observatory (5079 m a.s.l.) at the Ev-K2-CNR Pyramid is shown to be affected by the advection of pollution aerosols from the populated regions of southern Nepal and the Indo-Gangetic plains. Such an impact is observed along most of the period April 2006-March 2007 addressed here, with a minimum in the monsoon season. Backtrajectoryanalysis indicates long-range transport episodes occurring in this year to originate mainly in the west Asian deserts. At this high altitude site, the measured aerosol optical depth is observed to be about one order of magnitude lower than the one measured at Ghandi College (60 m a.s.l.), in the IndoGangetic basin. As for Ghandi College, and in agreement with the in situ ground observations at the Pyramid, the fine mode aerosol optical depth maximizes during winter and minimizes in the monsoon season. Conversely, total optical depth maximizes during the monsoon due to the occurrence of elevated, coarse particle layers. Possible origins of these particles are wind erosion from the surrounding peaks and hydrated/cloud-processed aerosols. Assessment of the aerosol radiative forcing is then expected to be hampered by the presence of these high altitude particle layers, which impede an effective, continuous measurement of anthropogenic aerosol radiative properties from sky radiance inversions and/or ground measurements alone. Even though the retrieved absorption coefficients of pollution aerosols were rather large (single scattering albedo of the order of Correspondence to: G. P. Gobbi (g.gobbi@isac.cnr.it) 0.6-0.9 were observed in the month of April 2006), the corresponding low optical depths (∼0.03 at 500 nm) are expected to limit the relevant radiative forcing. Still, the high specific forcing of this aerosol and its capability of altering snow surface albedo provide good reasons for continuous monitoring.

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Dust events in Kanpur, northern India: Chemical evidence for source and implications to radiative forcing

Cited by 118 publications

References 13 publications

Classification of aerosol properties derived from AERONET direct sun data

Classification of aerosol properties derived from AERONET direct sun data

Seasonal variations of water-soluble organic carbon, dicarboxylic acids, ketocarboxylic acids, and α-dicarbonyls in Central Himalayan aerosols

Sunphotometry of the 2006–2007 aerosol optical/radiative properties at the Himalayan Nepal Climate Observatory-Pyramid (5079 m a.s.l.)

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