A study of aerosol optical depth in the central Indian region (17.3–8.6°N) during ISRO-GBP field campaign

Singh, Sachchidanand; Singh, Bhupender; Gera, B. S.; Srivastava, Manoj; Dutta, H. N.; Garg, Sandeep; Singh, R. P.

doi:10.1016/j.atmosenv.2006.01.033

Cited by 18 publications

(13 citation statements)

References 13 publications

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“…Among the 14,651 point observations,~70% of values lie above 0.6 (at 500 nm) implying the prevalence of highly turbid atmosphere over Delhi, throughout the year. These observations are in line with the earlier reported values of AOD, although for a relatively much shorter durations, from Delhi Pandithurai et al, 2008], and are also comparable with the previous findings from other sites in the IGP [Jethva et al, 2005;Singh et al, 2006;Giles et al, 2011;Eck et al, 2012].…”

Section: Daily Monthly and Seasonal Variation Of Aod And Angstrom Pasupporting

confidence: 83%

Aerosol climatology at Delhi in the western Indo‐Gangetic Plain: Microphysics, long‐term trends, and source strengths

et al. 2013

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[1] We present the climatology of aerosol microphysics, its trends, and impact of potential sources based on the long term measurements (for a period of 11.5 years from December 2001 to May 2012) of aerosol optical depths (AOD) in the spectral range 340-1020 nm from an urban center Delhi (28.6 N, 77.3 E, 238 m mean sea level) in the western Indo-Gangetic Plain (IGP). The study is the first ever long-term characterization of aerosols over the western IGP from the ground-based measurements. AODs are known to affect the air quality, visibility, radiative balance, and cloud microphysics of the region and IGP is one of the highest populated and polluted regions of the world. Our measurements show consistently high AOD during the entire period of observation. The seasonal variations of spectral AODs and Angstrom parameters are generally consistent every year. The AODs show a weak but statistically significant (in 95% confidence level) decreasing trend approximately À0.02/year at 500 nm, possibly, modulated by the pre-monsoon heavy dust loading during the first half of the observation period. The climatological monthly mean AOD at shorter wavelengths peaks twice, during June and November, while at longer wavelengths it shows only one peak in June. The annual variations of Angstrom exponent, a and its derivative, a′ suggest the prevalence of multi-modal aerosol size distributions at Delhi. The coarse-mode aerosols dominate during summer (March-June) and monsoon (July-September) seasons, whereas fine/accumulation mode enhances during post-monsoon (October-November) and winter (December-February) seasons. Potential advection pathways have been identified using concentration weighted trajectory (CWT) analysis of the 5 day isentropic air mass back trajectories at the observation site and their seasonal variations are discussed.

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Section: Daily Monthly and Seasonal Variation Of Aod And Angstrom Pasupporting

confidence: 83%

Aerosol climatology at Delhi in the western Indo‐Gangetic Plain: Microphysics, long‐term trends, and source strengths

et al. 2013

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“…This campaign found notable pollution levels throughout the country (Moorthy et al, 2005b;Niranjan et al, 2005;Jayaraman et al, 2006;Nair et al, 2006;Singh et al, 2006). Coastal regions were found to usually have higher aerosol mass densities (50-150 µg/m 3 ) than in the semiarid interior continent (typically around or below 30 µg/m 3 ); small regions of enhanced aerosol mass densities were found around industrialized and urban centers in both coastal and inland regions.…”

Section: Overview Of Indoex and Other Regional Field Campaignsmentioning

confidence: 99%

“…However, in the context of this section it is worth briefly discussing two recent, major field campaigns which have provided significant information on the continental pollution levels over the last several years: ICARB (2006), and a 2-part campaign, also sponsored by the ISRO-GBP, in February and December 2004. ICARB was already noted above; in addition to the outflow observations, it included an intense, coordinated sampling at several continental sites (e.g., Beegum et al, 2008;Dumka et al, 2008;Singh et al, 2008;Badarinath and Kharol, 2008;Niranjan et al, 2008).…”

Section: Overview Of Indoex and Other Regional Field Campaignsmentioning

confidence: 99%

Atmospheric pollutant outflow from southern Asia: a review

2010

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Abstract. Southern Asia, extending from Pakistan and Afghanistan to Indonesia and Papua New Guinea, is one of the most heavily populated regions of the world. Biofuel and biomass burning play a disproportionately large role in the emissions of most key pollutant gases and aerosols there, in contrast to much of the rest of the Northern Hemisphere, where fossil fuel burning and industrial processes tend to dominate. This results in polluted air masses which are enriched in carbon-containing aerosols, carbon monoxide, and hydrocarbons. The outflow and long-distance transport of these polluted air masses is characterized by three distinct seasonal circulation patterns: the winter monsoon, the summer monsoon, and the monsoon transition periods. During winter, the near-surface flow is mostly northeasterly, and the regional pollution forms a thick haze layer in the lower troposphere which spreads out over millions of square km between southern Asia and the Intertropical Convergence Zone (ITCZ), located several degrees south of the equator over the Indian Ocean during this period. During summer, the heavy monsoon rains effectively remove soluble gases and aerosols. Less soluble species, on the other hand, are lifted to the upper troposphere in deep convective clouds, and are then transported away from the region by strong upper tropospheric winds, particularly towards northern Africa and the Mediterranean in the tropical easterly jet. Part of the pollution can reach the tropical tropopause layer, the gateway to the stratosphere. During the monsoon transition periods, the flow across the Indian Ocean is primarily zonal, and strong pollution plumes originating from both southeastern Asia and from Africa spread across the central Indian Ocean. This paper provides a review of the current state of knowledge based on the many observational and modeling studies over the last decades that have examined the southern AsianCorrespondence to: M. G. Lawrence (mark.lawrence@mpic.de) atmospheric pollutant outflow and its large scale effects. An outlook is provided as a guideline for future research, pointing out particularly critical issues such as: resolving discrepancies between top down and bottom up emissions estimates; assessing the processing and aging of the pollutant outflow; developing a better understanding of the observed elevated pollutant layers and their relationship to local sea breeze and large scale monsoon circulations; and determining the impacts of the pollutant outflow on the Asian monsoon meteorology and the regional hydrological cycle, in particular the mountain cryospheric reservoirs and the fresh water supply, which in turn directly impact the lives of over a billion inhabitants of southern Asia.

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“…Toward summer, as the land gets dry due to increased solar heating, the conditions become more conducive for picking up of dust from arid and semi-arid regions of central western India. The dust storm episodes produce enormous amount of coarse-mode natural aerosols causing substantial reduction in visibility and radiation f lux reaching the surface during summer (Gautam et al, 2010;Pandithurai et al, 2008;Prasad et al, 2007;Singh et al, 2006). The Delhi aerosol is best represented by a combination of urban and desert aerosol ty pes which is the result of the coarse sand and dust particles being gradually added in already polluted (vehicular and industrial origin) atmosphere of Delhi (Singh et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

Estimation of Motor Vehicle Toxic Emissions and Concentrations in Metropolitan City of Delhi

Amrit¹,

Mishra²

2017

IJTTE

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Road transport emission has been on continuous rise due to revolution in the automobile industry and public mobility demand. Emissions from motor vehicles have been one of the primary pollution sources in the metropolitan area of Delhi having a noticeable impact on ambient air quality. Volatile organic compounds, polycyclic aromatic hydrocarbons and carbonyl compounds are the major organic pollutants in urban environment. This objective of this study was to estimate the emission and concentration of Benzene, Total PAHs, and Total VOCs at 36 urban transport corridors of Delhi city. After analyzing the traffic scenario as well as toxic vehicular pollutants at all the transport corridor, the highest emission and concentration of Benzene, Total PAHs, and Total VOCs was found at ITO Bridge (3.71 Kg/ Day; 13.86 µg/m 3 ), ISBT Flyover (86.22 Kg/Day; 322.12 µg/m 3 ) and Nizamuddin Bridge (516.44 Kg/day; 1929.33 µg/m 3 ) respectively, whereas the Auchandi Road transport corridor showed the lowest emission as well as concentration of Benzene (0.21 Kg/Day; 0.78 µg/ m 3 ) and VOCs (26.91 Kg/day; 100.53 µg/m 3 ). Due to comparatively very less traffic and restriction on the entry of heavy vehicles at Sansad Marg transport corridor, very low emission and concentration of PAH (11.31 Kg/day; 42.27 µg/m 3 ) was found.

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A study of aerosol optical depth in the central Indian region (17.3–8.6°N) during ISRO-GBP field campaign

Cited by 18 publications

References 13 publications

Aerosol climatology at Delhi in the western Indo‐Gangetic Plain: Microphysics, long‐term trends, and source strengths

Aerosol climatology at Delhi in the western Indo‐Gangetic Plain: Microphysics, long‐term trends, and source strengths

Atmospheric pollutant outflow from southern Asia: a review

Estimation of Motor Vehicle Toxic Emissions and Concentrations in Metropolitan City of Delhi

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