Aerosols cause intraseasonal short-term suppression of Indian monsoon rainfall

Dave, Prashant; Bhushan, Mani; Venkataraman, Chandra

doi:10.1038/s41598-017-17599-1

Cited by 51 publications

(15 citation statements)

References 64 publications

(86 reference statements)

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“…Recent observational evidence also suggests that natural and anthropogenic aerosols, can affect daily-scale rainfall events over South Asia, including dry spells (Vinoj et al 2014;Dave et al 2017). The relative influence of local and remote aerosols on historical changes in daily-scale rainfall events in the presence of other external climate forcings is yet to be examined.…”

Section: Introductionmentioning

confidence: 99%

Disentangling the influence of local and remote anthropogenic aerosols on South Asian monsoon daily rainfall characteristics

et al. 2018

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Wet and dry periods within the South Asian summer monsoon season can have acute societal impacts. Recent studies have identified changes in daily rainfall characteristics of the monsoon, but the underlying causes are poorly understood. In particular, although the dominant role of anthropogenic aerosols in shaping historical changes in seasonal-mean monsoon rainfall has been documented, their influence on daily-scale rainfall remains unconstrained. Using an ensemble of single-forcing climate simulations, we find that anthropogenic aerosols have a stronger influence on late-20 th century changes in the frequency of wet events, dry events and rainless days, compared with other climate forcings. We also investigate the role of aerosol-cloud interactions ("indirect effects") in the total aerosol response, and the contribution of aerosols emitted from South Asia versus from remote sources. Based on additional simulations with the GFDL-CM3 climate model, we find that the simulated aerosol response over South Asia is largely associated with aerosol-indirect effects. In addition, local aerosols suppress wet-event frequency and enhance dry-event frequency over eastern-central India, where increases in aerosol loading are the largest. Remote aerosols cause a north-south dipole pattern of change in mean rainfall over India and fewer rainless days over western India. However, the overall spatial response of South Asian rainfall characteristics to total aerosol forcing is substantially influenced by the non-linear climate response to local and remote aerosols. Together, our results suggest that understanding the influence of different aerosol emissions trajectories on the regional climate dynamics is critical for effective climate-risk management in this populated, vulnerable region.

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Section: Introductionmentioning

confidence: 99%

Disentangling the influence of local and remote anthropogenic aerosols on South Asian monsoon daily rainfall characteristics

et al. 2018

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“…Many studies worldwide have examined the relative contributions of organic species to atmospheric aerosol, with oxalate typically having the highest contribution among dicarboxylic acids (Kawamura and Kaplan, 1987;Kawamura and Ikushima, 1993;Kawamura and Sakaguchi, 1999;Sorooshian et al, 2007a;Hsieh et al, 2007Hsieh et al, , 2008Aggarwal and Kawamura, 2008;Deshmukh et al, 2012Deshmukh et al, , 2018Li et al, 2015;Hoque et al, 2017;Kunwar et al, 2019). Oxalate was the dominant water-soluble organic species for all 12 MOUDI sets, with oxalate having the highest contribution to the organic aerosol in MO12 (88.7 % of total organic aerosol).…”

Section: Variability Of Water-soluble Organic Speciesmentioning

confidence: 99%

Long-range aerosol transport and impacts on size-resolved aerosol composition in Metro Manila, Philippines

et al. 2020

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This study analyzes long-range transport of aerosol and aerosol chemical characteristics based on instances of high-and low-aerosol-loading events determined via ground-based size-resolved aerosol measurements collected at the Manila Observatory in Metro Manila, Philippines, from July to October 2018. Multiple data sources, including models, remote sensing, and in situ measurements, are used to analyze the impacts of long-range aerosol transport on Metro Manila and the conditions at the local and synoptic scales facilitating this transport. Through the use of case studies, evidence of long-range transport of biomass burning aerosol and continental emissions is identified in Metro Manila. Long-range transport of biomass burning aerosol from the Maritime Continent, bolstered by southwesterly flow and permitted by low rainfall, was identified through model results and the presence of biomass burning tracers (e.g., K, Rb) in the ground-based measurements. The impacts of emissions transported from continental East Asia on the aerosol characteristics in Metro Manila are also identified; for one of the events analyzed, this transport was facilitated by the nearby passage of a typhoon. Changes in the aerosol size distributions, water-soluble chemical composition, and contributions of various organic aerosol species to the total water-soluble organic aerosol were examined for the different cases. The events impacted by biomass burning transport had the overall highest concentration of water-soluble organic acids, while the events impacted by long-range transport from continental East Asia showed high percent contributions from shorter-chain dicarboxylic acids (i.e., oxalate) that are often representative of photochemical and aqueous processing in the atmosphere. The low-aerosolloading event was subject to a larger precipitation accumulation than the high-aerosol events, indicative of wet scavenging as an aerosol sink in the study region. This low-aerosol event was characterized by a larger relative contribution from supermicrometer aerosols and had a higher percent contribution from longer-chain dicarboxylic acids (i.e., maleate) to the water-soluble organic aerosol fraction, indicating the importance of both primary aerosol emissions and local emissions.

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“…Used with permission intensification of monsoon precipitation over central India (Vinoj et al 2014). Additionally, aerosols can cause suppression of rainfall during monsoon breaks via atmospheric stabilization and increased moisture divergence (Dave et al 2017).…”

Section: Box 53: How Aerosols Impact Monsoon Precipitation?mentioning

confidence: 99%