Origin of surface and columnar Indian Ocean Experiment (INDOEX) aerosols using source‐ and region‐tagged emissions transport in a general circulation model

Verma, Shubha; Venkataraman, Chandra; Boucher, Oliviér

doi:10.1029/2007jd009538

Cited by 34 publications

(26 citation statements)

References 41 publications

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“…21. These strong gradients, including the sharp gradient across the ITCZ, were first noted in measurements made on the pre-INDOEX and INDOEX ship cruises (e.g., Rhoads et al, 1997;Moorthy et al, 1997;Jayaraman et al, 1998Jayaraman et al, , 1999Jayaraman et al, , 2001Satheesh et al, 1998;Naja et al, 1999;Stehr et al, 2002;Quinn et al, 2002;Chand et al, 2001Chand et al, , 2003Kamra et al, 2003;Norman et al, 2003;Nair et al, 2004;Naja et al, 2004), as well as in aircraft observations during INDOEX (e.g., Ramanathan et al, 2001;Reiner et al, 2001;Gabriel et al, 2002a;Pelon et al, 2002;de Reus et al, 2002), and shortly thereafter were corroborated to be a general feature of the broader region based on numerous pieces of evidence, including further in situ observations, satellite retrievals and model simulations (e.g., Rajeev et al, 2000Rajeev et al, , 2004Rajeev and Ramanathan, 2001;Collins et al, 2001Collins et al, , 2002de Laat et al, 2001a, b;Lelieveld et al, 2001;Lawrence et al, 2003a;Minvielle et al, 2004a, b;Moorthy et al, 2005a;Satheesh et al, 2006a, b;Vinoj et al, 2007;Verma et al, 2008). In addition to this generally strong gradient of pollutants in the SAW-ABC, these observations and modeling studies have also shown a very abrupt transition between the polluted NH air masses and more pristine SH air in the MBL at the ITCZ, which can be considered a "chemical ITCZ" …”

Section: Transit Times Lofting In the Itcz And Interhemispheric Exchmentioning

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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Section: Transit Times Lofting In the Itcz And Interhemispheric Exchmentioning

confidence: 99%

Atmospheric pollutant outflow from southern Asia: a review

2010

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“…Elevated aerosols loading was observed in a remote marine environment over the Arabian Sea during INDOEX 1999. The chemical transport models have been used widely for atmospheric simulations over southern Asia during the INDOEX period (Rajeev et al, 2000;Rasch et al, 2001;Podgorny and Ramanathan, 2001;Reddy et al, 2004;Verma et al, 2008Verma et al, , 2012, and have shown a predominance of sulphate in the south Asian region. Most of the INDOEX studies emphasize the underestimated impact of aerosols on climate Ramanathan et al, 2002;UNEP, 2002).…”

Section: Introductionmentioning

confidence: 99%

“…Aerosol transport and its impact on radiative forcing were estimated over the tropical Indian Ocean during INDOEX (Krishnamurty et al, 1998;Podgorny et al, 2000;Rajeev et al, 2001). General circulation model (GCM) simulations over south Asia during the INDOEX period with the high resolution regional emissions information (Reddy et al, 2004;Verma et al, 2008Verma et al, , 2012 indicate the likely contribution of emissions from regions outside India to aerosol loading over the Indian subcontinent and adjoining oceans.…”

Section: Introductionmentioning

confidence: 99%

Variations in sulphate aerosols concentration during winter monsoon season for two consecutive years using a general circulation model

Verma¹,

Boucher²,

Upadhyaya³

et al. 2013

Atmósfera

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RESUMENDurante las investigaciones de campo del Experimento del Océano Índico (INDOEX, por sus siglas en inglés), se llevaron a cabo mediciones exhaustivas de la composición química y el contenido de aerosoles de la atmósfera para estudiar el transporte de largo alcance de la contaminación atmosférica desde el sur y el sureste de Asia hacia el Océano Índico, durante la estación seca del monzón en 1998 y 1999. Este trabajo analiza las variaciones temporales y espaciales de los aerosoles y su forzamiento durante la estación invernal (de enero a marzo) en la primera fase de campo (FFP, por sus siglas en inglés) y la fase intensiva de campo (IFP, por sus siglas en inglés) del INDOEX, las cuales se llevaron a cabo en 1998 y 1999, respectivamente. Se utilizó un modelo interactivo de química y aerosoles (LMDZ.3.3) para investigar las variaciones espaciales en la distribución de aerosoles troposféricos de sulfato durante 1998 y 1999. Los resultados de este modelo muestran un incremento considerable en las concentraciones de aerosoles de sulfato, el forzamiento radiativo y la profundidad óptica en el subcontinente indio y zonas oceánicas circundantes entre la FFP y la IFP del INDOEX. También se simuló un incremento importante en el transporte de aerosoles de sulfato desde la zona continental hacia el Océano Índico durante el monzón de invierno de 1999. El forzamiento radiativo medio en el INDOEX-FFP de 1998 fue de -1.2 Wm -2 y aumentó a -1.85 Wm -2 durante el INDOEX-IFP de 1999. Los resultados del modelo arrojan una profundidad óptica media de aerosoles de sulfato de 0.08 y 0.14 sobre el subcontinente indio en 1998 y 1999, respectivamente. Estos resultados sugieren que las actividades antropogénicas en dicha región pueden afectar de manera significativa al entorno oceánico circundante. ABSTRACTDuring the field cruises of the Indian Ocean Experiment (INDOEX) extensive measurements on the atmospheric chemical and aerosol composition are undertaken to study the long-range transport of air pollution from south and southeast Asia towards the Indian Ocean during the dry monsoon season in 1998 and 1999. The present paper discusses the temporal and spatial variations in aerosols and aerosol forcing during the winter monsoon season (January-March) for INDOEX first field phase (FFP) in 1998 and INDOEX intensive field phase (IFP) in 1999. An interactive chemistry/aerosol model (LMDZ.3.3) is used to investigate the variation in the spatial distribution of tropospheric sulphate aerosols during 1998 and 1999. The model results depict major enhancement in the sulphate aerosol concentrations, radiative forcing (RF) and optical depth over the Indian subcontinent and adjoining marine areas between INDOEX-FFP and IFP. A significant increase in transport of sulphate aerosols from the continents to the Indian Ocean region has also been simulated during Atmósfera 26(3), 359-367 (2013)

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“…In addition to pollution, the aerosol load of northern India and Nepal is affected by important natural contributions. Mineral dust from the surrounding West Asian deserts (or even from the Sahara and Arabian ones) can constitute a large fraction of the aerosol optical depth (AOD), particularly during the premonsoon season (March-May), when dust is observed to mix with anthropogenic pollution (e.g., Shresta et al, 2000;Chinnam et al, 2006;Prasad and Singh, 2007;Liu et al, 2008;Verma et al, 2008). In this context, the assessment of the radiative effects of anthropogenic vs. natural aerosols in this region represents an intricate task (e.g., Dey and Tripathi, 2008).…”

Section: Introductionmentioning

confidence: 99%

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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Origin of surface and columnar Indian Ocean Experiment (INDOEX) aerosols using source‐ and region‐tagged emissions transport in a general circulation model

Cited by 34 publications

References 41 publications

Atmospheric pollutant outflow from southern Asia: a review

Atmospheric pollutant outflow from southern Asia: a review

Variations in sulphate aerosols concentration during winter monsoon season for two consecutive years using a general circulation model

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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