Spring-Time Enhancement in Aerosol Burden over a High-Altitude Location in Western Trans-Himalaya:Results from Long-Term Observations

Kompalli, Sobhan Kumar; Lakshmi, N. B.; Moorthy, K. Krishna

doi:10.18520/cs/v111/i1/117-131

Cited by 15 publications

(3 citation statements)

References 45 publications

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“…Recent studies using in-situ and remote sensing methods have shown a spring-time enhancement in the aerosol optical depth and black carbon (BC) concentration in the lower free troposphere (below 5 km) over the plains and also over the Himalayas (Prijith et al, 5 2016;Kompalli et al, 2016;Gogoi et al, 2014), and a northward increasing gradient in the amplitude and altitude of the aerosol induced atmospheric heating Satheesh et al (2008). In a recent study Nair et al (2016) have found large enhancement in aerosol absorption in the lower free troposphere over the IGP during spring.…”

Section: Introductionmentioning

confidence: 99%

Large contrast in the vertical distribution of aerosol optical properties and radiative effects across the Indo-Gangetic Plain during SWAAMI-RAWEX campaign

Vaishya¹,

Kompalli²,

Jayachandran³

et al. 2018

Preprint

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Abstract. Measurements of the vertical profiles of the optical properties (namely the extinction&#8201;/&#8201;scattering and absorption coefficients; respectively &#963;ext&#8201;/&#8201;&#963;scat&#8201;/&#8201;&#963;abs) of aerosols have been made across the Indo-Gangetic Plain (IGP) using an instrumented aircraft operated from three base stations (Jodhpur (JDR) representing the semiarid western IGP; Varanasi (VNS) the central IGP characterized by significant anthropogenic activities; and the industrialised coastal location in the eastern end of the IGP (Bhubaneswar, BBR)), just prior to the onset of the Indian Summer monsoon. The vertical profiles depicted region-specific absorption characteristics, while the scattering characteristics remained fairly uniform across the region, leading to a west-east gradient in the vertical structure of single scattering albedo (SSA). Integrated from near ground to 3&#8201;km, the highest absorption coefficient and hence the lowest SSA occurred in the central IGP (Varanasi). Size distribution, inferred from the spectral variation of the scattering coefficient, showed a gradual shift from coarse particle dominance in the western IGP to strong accumulation dominance in the eastern coast with the central IGP coming in-between, arising from a change in the aerosol type from predominantly natural (dust and sea-salt) type in the western IGP to highly anthropogenic type (industrial emissions, fossil fuel and biomass combustion) in the eastern IGP; the central IGP exhibiting a mixture of both. Aerosol induced short-wave radiative forcing, estimated using altitude resolved SSA information, revealed significant atmospheric warming in the central IGP while a top-of-atmosphere cooling is seen, in general, in the IGP. Atmospheric heating rate profiles, estimated using altitude resolved SSA and column average SSA, revealed considerable underestimation in the latter case, emphasising the importance and necessity of having altitude resolved SSA information as against a single value for the entire column.

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Section: Introductionmentioning

confidence: 99%

Large contrast in the vertical distribution of aerosol optical properties and radiative effects across the Indo-Gangetic Plain during SWAAMI-RAWEX campaign

Vaishya¹,

Kompalli²,

Jayachandran³

et al. 2018

Preprint

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show abstract

“…In addition to assessing human health risks, source apportionment studies will help in formulating effective mitigation strategies for ambient PM. The Himalayas, in the north of India, constitute a pristine environment, and several studies have reported the influence of atmospheric aerosols emitted from the anthropogenic activities from the neighboring polluted regions [16][17][18][19]. However, detailed studies on particulate pollution from the industrialized areas in the proximity of the Himalayas are scarce.…”

Section: Electronic Supplementary Materialsmentioning

confidence: 99%

Sources and health risks of atmospheric particulate matter at Bhagwanpur, an industrial site along the Himalayan foothills

et al. 2020

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Temporal variations in atmospheric particulate matter (PM) were studied in Bhagwanpur-a data-deficient area located along the foothills of the Himalayas. The concentrations of respirable suspended particulate matter (RSPM) and PM 0.4-10 µm (categorized into eight size fractions) were measured during winter and summer of 2014-2015. The RSPM concentration over a 24-h period was found to be 259.6 ± 52.6 µg/m 3 , which is 2.6 times greater than the permissible limit set by the Indian National Ambient Air Quality Standards. A significant difference (p < 0.05, t test) in RSPM with seasons was observed with winter maximum (284.6 ± 48.6 µg/m 3) and summer minimum (234.5 ± 44.8 µg/m 3). Size fractionated PM measurements revealed maximum concentration (36.4 ± 5.2 µg/m 3) in PM 9.0-10.0 µm, while least concentration was observed in PM 2.1-3.3 µm (16.8 ± 2.3 µg/m 3). Further, on quantification of 13 chemical species associated with RSPM, it was observed that mass concentration followed the trend of Ca > K > Mg > Al > Zn > Fe > Mn > Cr > Co > Ni > Cu > Pb > C d. Source apportionment through principal component analysis revealed the sources such as industrial, vehicular, and crustal. The excess cancer risk for Cr was about 2.7 times higher than the tolerance level (10 −4), while only Pb was below the safe limit (10 −6). However, total ECR for Cr, Cd, Pb, and Ni was about 3 times higher than the tolerance level. Three-day air mass back trajectory analysis reveals that emissions from biomass burning over the neighbouring regions adversely affect the air quality at the study site. The results of this study can be utilized toward the effective implementation of environmental regulations at the study site.

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“…Analysing multi-year satellite (CALIPSO) data, Prijith et al (2016) have not only confirmed the existence of high-altitude aerosol layers and their meridional gradient in the vertical extent during pre-monsoon periods over the Indian region, but have also shown that mineral dust aerosol forms the dominant component of this layer. Kompalli et al (2016) have reported springtime enhancement in columnar aerosol optical depth (AOD) and BC over Hanle, a western trans-Himalayan high-altitude observational location (4.5 km amsl). They attributed this enhancement to summertime lifting of aerosols over the region west to southwest of Hanle and their subsequent long-range transport.…”

Section: Introductionmentioning

confidence: 99%

Possible climatic implications of high-altitude black carbon emissions

et al. 2017

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Abstract. On account of its strong absorption of solar and terrestrial radiation, black carbon (BC) aerosol is known to impact large-scale systems, such as the Asian monsoon and the Himalayan glaciers, in addition to affecting the thermal structure of the lower atmosphere. While most studies focus on the near-surface abundance and impacts of BC, our study examines the implications of sharp and confined layers of high BC concentration (called elevated BC layers) at altitudes more than 4 km over the Indian region using the online regional chemistry transport model (WRF-Chem) simulations. These elevated BC layers were revealed in the recent in situ measurements using high-altitude balloons carried out on 17 March 2010, 8 January 2011 and 25 April 2011. Our study demonstrates that high-flying aircraft (with emissions from the regionally fine-tuned MACCity inventory) are the most likely cause of these elevated BC layers. Furthermore, we show that such aircraft-emitted BC can be transported to upper tropospheric or lower stratospheric heights ( ∼ 17 km) aided by the strong monsoonal convection occurring over the region, which is known to overshoot the tropical tropopause, leading to the injection of tropospheric air mass (along with its constituent aerosols) into the stratosphere. We show observational evidence for such an intrusion of tropospheric BC into the stratosphere over the Indian region using extinction coefficient and particle depolarisation ratio data from CALIOP Lidar on-board the CALIPSO satellite. We hypothesise that such intrusions of BC into the lower stratosphere and its consequent longer residence time in the stratosphere have significant implications for stratospheric ozone, especially considering the already reported ozone-depleting potential of BC.

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Spring-Time Enhancement in Aerosol Burden over a High-Altitude Location in Western Trans-Himalaya:Results from Long-Term Observations

Abstract: Long-term measurements (from

Cited by 15 publications

References 45 publications

Large contrast in the vertical distribution of aerosol optical properties and radiative effects across the Indo-Gangetic Plain during SWAAMI-RAWEX campaign

Large contrast in the vertical distribution of aerosol optical properties and radiative effects across the Indo-Gangetic Plain during SWAAMI-RAWEX campaign

Sources and health risks of atmospheric particulate matter at Bhagwanpur, an industrial site along the Himalayan foothills

Possible climatic implications of high-altitude black carbon emissions

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