Quantifying snow darkening and atmospheric radiative effects of black carbon and dust on the South Asian monsoon and hydrological cycle: experiments using variable-resolution CESM
<p>Black carbon (BC) and dust impart significant effects on the South Asian monsoon (SAM), which is responsible for <span class="inline-formula">∼80</span>  % of the region's annual precipitation. This study implements a variable-resolution (VR)...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2019-09-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://www.atmos-chem-phys.net/19/12025/2019/acp-19-12025-2019.pdf |
| _version_ | 1818777160552284160 |
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| author | S. Rahimi X. Liu C. Wu C. Wu W. K. Lau H. Brown M. Wu Y. Qian |
| author_facet | S. Rahimi X. Liu C. Wu C. Wu W. K. Lau H. Brown M. Wu Y. Qian |
| author_sort | S. Rahimi |
| collection | DOAJ |
| description | <p>Black carbon (BC) and dust impart significant effects on the South Asian
monsoon (SAM), which is responsible for <span class="inline-formula">∼80</span>  % of the
region's annual precipitation. This study implements a variable-resolution
(VR) version of the Community Earth System Model (CESM) to quantify two
radiative effects of absorbing BC and dust on the SAM. Specifically, this
study focuses on the snow darkening effect (SDE), as well as how these
aerosols interact with incoming and outgoing radiation to facilitate an
atmospheric response (i.e., aerosol–radiation interactions, ARIs). By running
sensitivity experiments, the individual effects of SDE and ARI are
quantified, and a theoretical framework is applied to assess these aerosols'
impacts on the SAM. It is found that ARIs of absorbing aerosols warm the
atmospheric column in a belt coincident with the May–June averaged location
of the subtropical jet, bringing forth anomalous upper-tropospheric
(lower-tropospheric) anticyclogenesis (cyclogenesis) and divergence
(convergence). This anomalous arrangement in the mass fields brings forth
enhanced rising vertical motion across South Asia and a stronger westerly
low-level jet, the latter of which furnishes the Indian subcontinent with
enhanced Arabian Gulf moisture. Precipitation increases of 2 mm d<span class="inline-formula"><sup>−1</sup></span> or
more (a 60 % increase in June) result across much of northern India from
May through August, with larger anomalies (<span class="inline-formula">+5</span> to <span class="inline-formula">+10</span> mm d<span class="inline-formula"><sup>−1</sup></span>) in the
western Indian mountains and southern Tibetan Plateau (TP) mountain ranges due to orographic
and anabatic enhancement. Across the Tibetan Plateau foothills, SDE by BC
aerosols drives large precipitation anomalies of > 6 mm d<span class="inline-formula"><sup>−1</sup></span>
(a 21 %–26 % increase in May and June), comparable to ARI of absorbing
aerosols from April through August. Runoff changes accompany BC SDE-induced
snow changes across Tibet, while runoff changes across India result
predominantly from dust ARI. Finally, there are large differences in the
simulated SDE between the VR and traditional 1<span class="inline-formula"><sup>∘</sup></span> simulations, the latter
of which simulates a much stronger SDE and more effectively modifies the
regional circulation.</p> |
| first_indexed | 2024-12-18T11:24:25Z |
| format | Article |
| id | doaj.art-0649ddb57c4141a3bc8d8b1a184ea436 |
| institution | Directory Open Access Journal |
| issn | 1680-7316 1680-7324 |
| language | English |
| last_indexed | 2024-12-18T11:24:25Z |
| publishDate | 2019-09-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Chemistry and Physics |
| spelling | doaj.art-0649ddb57c4141a3bc8d8b1a184ea4362022-12-21T21:09:44ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242019-09-0119120251204910.5194/acp-19-12025-2019Quantifying snow darkening and atmospheric radiative effects of black carbon and dust on the South Asian monsoon and hydrological cycle: experiments using variable-resolution CESMS. Rahimi0X. Liu1C. Wu2C. Wu3W. K. Lau4H. Brown5M. Wu6Y. Qian7Department of Atmospheric Science, University of Wyoming, 1000 E. University, 1000 E. University Ave. Laramie, WY 82071, USADepartment of Atmospheric Science, University of Wyoming, 1000 E. University, 1000 E. University Ave. Laramie, WY 82071, USADepartment of Atmospheric Science, University of Wyoming, 1000 E. University, 1000 E. University Ave. Laramie, WY 82071, USAInternational Center for Climate and Environment Sciences, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, 100029, ChinaEarth System Science Interdisciplinary Center, University of Maryland, College Park, MD 20742, USADepartment of Atmospheric Science, University of Wyoming, 1000 E. University, 1000 E. University Ave. Laramie, WY 82071, USADepartment of Atmospheric Science, University of Wyoming, 1000 E. University, 1000 E. University Ave. Laramie, WY 82071, USAAtmospheric Sciences and Global Change, Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA 99352, USA<p>Black carbon (BC) and dust impart significant effects on the South Asian monsoon (SAM), which is responsible for <span class="inline-formula">∼80</span>  % of the region's annual precipitation. This study implements a variable-resolution (VR) version of the Community Earth System Model (CESM) to quantify two radiative effects of absorbing BC and dust on the SAM. Specifically, this study focuses on the snow darkening effect (SDE), as well as how these aerosols interact with incoming and outgoing radiation to facilitate an atmospheric response (i.e., aerosol–radiation interactions, ARIs). By running sensitivity experiments, the individual effects of SDE and ARI are quantified, and a theoretical framework is applied to assess these aerosols' impacts on the SAM. It is found that ARIs of absorbing aerosols warm the atmospheric column in a belt coincident with the May–June averaged location of the subtropical jet, bringing forth anomalous upper-tropospheric (lower-tropospheric) anticyclogenesis (cyclogenesis) and divergence (convergence). This anomalous arrangement in the mass fields brings forth enhanced rising vertical motion across South Asia and a stronger westerly low-level jet, the latter of which furnishes the Indian subcontinent with enhanced Arabian Gulf moisture. Precipitation increases of 2 mm d<span class="inline-formula"><sup>−1</sup></span> or more (a 60 % increase in June) result across much of northern India from May through August, with larger anomalies (<span class="inline-formula">+5</span> to <span class="inline-formula">+10</span> mm d<span class="inline-formula"><sup>−1</sup></span>) in the western Indian mountains and southern Tibetan Plateau (TP) mountain ranges due to orographic and anabatic enhancement. Across the Tibetan Plateau foothills, SDE by BC aerosols drives large precipitation anomalies of > 6 mm d<span class="inline-formula"><sup>−1</sup></span> (a 21 %–26 % increase in May and June), comparable to ARI of absorbing aerosols from April through August. Runoff changes accompany BC SDE-induced snow changes across Tibet, while runoff changes across India result predominantly from dust ARI. Finally, there are large differences in the simulated SDE between the VR and traditional 1<span class="inline-formula"><sup>∘</sup></span> simulations, the latter of which simulates a much stronger SDE and more effectively modifies the regional circulation.</p>https://www.atmos-chem-phys.net/19/12025/2019/acp-19-12025-2019.pdf |
| spellingShingle | S. Rahimi X. Liu C. Wu C. Wu W. K. Lau H. Brown M. Wu Y. Qian Quantifying snow darkening and atmospheric radiative effects of black carbon and dust on the South Asian monsoon and hydrological cycle: experiments using variable-resolution CESM Atmospheric Chemistry and Physics |
| title | Quantifying snow darkening and atmospheric radiative effects of black carbon and dust on the South Asian monsoon and hydrological cycle: experiments using variable-resolution CESM |
| title_full | Quantifying snow darkening and atmospheric radiative effects of black carbon and dust on the South Asian monsoon and hydrological cycle: experiments using variable-resolution CESM |
| title_fullStr | Quantifying snow darkening and atmospheric radiative effects of black carbon and dust on the South Asian monsoon and hydrological cycle: experiments using variable-resolution CESM |
| title_full_unstemmed | Quantifying snow darkening and atmospheric radiative effects of black carbon and dust on the South Asian monsoon and hydrological cycle: experiments using variable-resolution CESM |
| title_short | Quantifying snow darkening and atmospheric radiative effects of black carbon and dust on the South Asian monsoon and hydrological cycle: experiments using variable-resolution CESM |
| title_sort | quantifying snow darkening and atmospheric radiative effects of black carbon and dust on the south asian monsoon and hydrological cycle experiments using variable resolution cesm |
| url | https://www.atmos-chem-phys.net/19/12025/2019/acp-19-12025-2019.pdf |
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