Tropospheric warming over the northern Indian Ocean caused by South Asian anthropogenic aerosols: possible impact on the upper troposphere and lower stratosphere

<p>Atmospheric concentrations of South Asian anthropogenic aerosols and their transport play a key role in the regional hydrological cycle. Here, we use the ECHAM6-HAMMOZ chemistry–climate model to show the structure and implications of the transport pathways of these aerosols during spring (M...

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Main Authors: S. Fadnavis, P. Chavan, A. Joshi, S. M. Sonbawne, A. Acharya, P. C. S. Devara, A. Rap, F. Ploeger, R. Müller
Format: Article
Language:English
Published: Copernicus Publications 2022-06-01
Series:Atmospheric Chemistry and Physics
Online Access:https://acp.copernicus.org/articles/22/7179/2022/acp-22-7179-2022.pdf
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author S. Fadnavis
P. Chavan
A. Joshi
S. M. Sonbawne
A. Acharya
P. C. S. Devara
A. Rap
F. Ploeger
R. Müller
author_facet S. Fadnavis
P. Chavan
A. Joshi
S. M. Sonbawne
A. Acharya
P. C. S. Devara
A. Rap
F. Ploeger
R. Müller
author_sort S. Fadnavis
collection DOAJ
description <p>Atmospheric concentrations of South Asian anthropogenic aerosols and their transport play a key role in the regional hydrological cycle. Here, we use the ECHAM6-HAMMOZ chemistry–climate model to show the structure and implications of the transport pathways of these aerosols during spring (March–May). Our simulations indicate that large amounts of anthropogenic aerosols are transported from South Asia to the northern Indian Ocean and western Pacific. These aerosols are then lifted into the upper troposphere and lower stratosphere (UTLS) by the ascending branch of the Hadley circulation, where they enter the westerly jet. They are further transported to the Southern Hemisphere (<span class="inline-formula">∼15</span>–30<span class="inline-formula"><sup>∘</sup></span> S) and downward (320–340 K) via westerly ducts over the tropical Atlantic (5<span class="inline-formula"><sup>∘</sup></span> S–5<span class="inline-formula"><sup>∘</sup></span> N, 10–40<span class="inline-formula"><sup>∘</sup></span> W) and Pacific (5<span class="inline-formula"><sup>∘</sup></span> S–5<span class="inline-formula"><sup>∘</sup></span> N, 95–140<span class="inline-formula"><sup>∘</sup></span> E). The carbonaceous aerosols are also transported to the Arctic, leading to local heating (0.08–0.3 K per month, an increase by 10 %–60 %).</p> <p>The presence of anthropogenic aerosols causes a negative radiative forcing (RF) at the top of the atmosphere (TOA) (<span class="inline-formula">−</span>0.90 <span class="inline-formula">±</span> 0.089 W m<span class="inline-formula"><sup>−2</sup>)</span> and surface (<span class="inline-formula">−</span>5.87 <span class="inline-formula">±</span> 0.31 W m<span class="inline-formula"><sup>−2</sup>)</span> and atmospheric warming (<span class="inline-formula">+</span>4.96 <span class="inline-formula">±</span> 0.24 W m<span class="inline-formula"><sup>−2</sup>)</span> over South Asia (60–90<span class="inline-formula"><sup>∘</sup></span> E, 8–23<span class="inline-formula"><sup>∘</sup></span> N), except over the Indo-Gangetic Plain (75–83<span class="inline-formula"><sup>∘</sup></span> E, 23–30<span class="inline-formula"><sup>∘</sup></span> N), where RF at the TOA is positive (<span class="inline-formula">+</span>1.27 <span class="inline-formula">±</span> 0.16 W m<span class="inline-formula"><sup>−2</sup>)</span> due to large concentrations of absorbing aerosols. The carbonaceous aerosols lead to in-atmospheric heating along the aerosol column extending from the boundary layer to the upper troposphere (0.1 to 0.4 K per month, increase by 4 %–60 %) and in the lower stratosphere at 40–90<span class="inline-formula"><sup>∘</sup></span> N (0.02 to 0.3 K per month, increase by 10 %–60 %). The increase in tropospheric heating due to aerosols results in an increase in water vapor concentrations, which are then transported from the northern Indian Ocean–western Pacific to the UTLS over 45–45<span class="inline-formula"><sup>∘</sup></span> N (increasing water vapor by 1 %–10 %).</p>
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spelling doaj.art-e7c04f7a4cd04b1db36cb200ccb9eea02022-12-22T02:29:57ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242022-06-01227179719110.5194/acp-22-7179-2022Tropospheric warming over the northern Indian Ocean caused by South Asian anthropogenic aerosols: possible impact on the upper troposphere and lower stratosphereS. Fadnavis0P. Chavan1A. Joshi2S. M. Sonbawne3A. Acharya4P. C. S. Devara5A. Rap6F. Ploeger7R. Müller8Indian Institute of Tropical Meteorology, Center for Climate Change Research, MoES, Pune, IndiaIndian Institute of Tropical Meteorology, Center for Climate Change Research, MoES, Pune, IndiaIndian Institute of Technology, Kharagpur, IndiaIndian Institute of Tropical Meteorology, Center for Climate Change Research, MoES, Pune, IndiaIndian Institute of Technology, Bhubneshwar, IndiaCentre of Excellence in ACOAST/ACESH, Amity University Haryana (AUH), Gurugram 122413, IndiaSchool of Earth and Environment, University of Leeds, Leeds, UKForschungszentrum Jülich GmbH, IEK-7, Jülich, GermanyForschungszentrum Jülich GmbH, IEK-7, Jülich, Germany<p>Atmospheric concentrations of South Asian anthropogenic aerosols and their transport play a key role in the regional hydrological cycle. Here, we use the ECHAM6-HAMMOZ chemistry–climate model to show the structure and implications of the transport pathways of these aerosols during spring (March–May). Our simulations indicate that large amounts of anthropogenic aerosols are transported from South Asia to the northern Indian Ocean and western Pacific. These aerosols are then lifted into the upper troposphere and lower stratosphere (UTLS) by the ascending branch of the Hadley circulation, where they enter the westerly jet. They are further transported to the Southern Hemisphere (<span class="inline-formula">∼15</span>–30<span class="inline-formula"><sup>∘</sup></span> S) and downward (320–340 K) via westerly ducts over the tropical Atlantic (5<span class="inline-formula"><sup>∘</sup></span> S–5<span class="inline-formula"><sup>∘</sup></span> N, 10–40<span class="inline-formula"><sup>∘</sup></span> W) and Pacific (5<span class="inline-formula"><sup>∘</sup></span> S–5<span class="inline-formula"><sup>∘</sup></span> N, 95–140<span class="inline-formula"><sup>∘</sup></span> E). The carbonaceous aerosols are also transported to the Arctic, leading to local heating (0.08–0.3 K per month, an increase by 10 %–60 %).</p> <p>The presence of anthropogenic aerosols causes a negative radiative forcing (RF) at the top of the atmosphere (TOA) (<span class="inline-formula">−</span>0.90 <span class="inline-formula">±</span> 0.089 W m<span class="inline-formula"><sup>−2</sup>)</span> and surface (<span class="inline-formula">−</span>5.87 <span class="inline-formula">±</span> 0.31 W m<span class="inline-formula"><sup>−2</sup>)</span> and atmospheric warming (<span class="inline-formula">+</span>4.96 <span class="inline-formula">±</span> 0.24 W m<span class="inline-formula"><sup>−2</sup>)</span> over South Asia (60–90<span class="inline-formula"><sup>∘</sup></span> E, 8–23<span class="inline-formula"><sup>∘</sup></span> N), except over the Indo-Gangetic Plain (75–83<span class="inline-formula"><sup>∘</sup></span> E, 23–30<span class="inline-formula"><sup>∘</sup></span> N), where RF at the TOA is positive (<span class="inline-formula">+</span>1.27 <span class="inline-formula">±</span> 0.16 W m<span class="inline-formula"><sup>−2</sup>)</span> due to large concentrations of absorbing aerosols. The carbonaceous aerosols lead to in-atmospheric heating along the aerosol column extending from the boundary layer to the upper troposphere (0.1 to 0.4 K per month, increase by 4 %–60 %) and in the lower stratosphere at 40–90<span class="inline-formula"><sup>∘</sup></span> N (0.02 to 0.3 K per month, increase by 10 %–60 %). The increase in tropospheric heating due to aerosols results in an increase in water vapor concentrations, which are then transported from the northern Indian Ocean–western Pacific to the UTLS over 45–45<span class="inline-formula"><sup>∘</sup></span> N (increasing water vapor by 1 %–10 %).</p>https://acp.copernicus.org/articles/22/7179/2022/acp-22-7179-2022.pdf
spellingShingle S. Fadnavis
P. Chavan
A. Joshi
S. M. Sonbawne
A. Acharya
P. C. S. Devara
A. Rap
F. Ploeger
R. Müller
Tropospheric warming over the northern Indian Ocean caused by South Asian anthropogenic aerosols: possible impact on the upper troposphere and lower stratosphere
Atmospheric Chemistry and Physics
title Tropospheric warming over the northern Indian Ocean caused by South Asian anthropogenic aerosols: possible impact on the upper troposphere and lower stratosphere
title_full Tropospheric warming over the northern Indian Ocean caused by South Asian anthropogenic aerosols: possible impact on the upper troposphere and lower stratosphere
title_fullStr Tropospheric warming over the northern Indian Ocean caused by South Asian anthropogenic aerosols: possible impact on the upper troposphere and lower stratosphere
title_full_unstemmed Tropospheric warming over the northern Indian Ocean caused by South Asian anthropogenic aerosols: possible impact on the upper troposphere and lower stratosphere
title_short Tropospheric warming over the northern Indian Ocean caused by South Asian anthropogenic aerosols: possible impact on the upper troposphere and lower stratosphere
title_sort tropospheric warming over the northern indian ocean caused by south asian anthropogenic aerosols possible impact on the upper troposphere and lower stratosphere
url https://acp.copernicus.org/articles/22/7179/2022/acp-22-7179-2022.pdf
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