Mechanisms for a remote response to Asian anthropogenic aerosol in boreal winter
Asian emissions of anthropogenic aerosols and their precursors have increased rapidly since 1980, with half of the increase since the pre-industrial era occurring in this period. Transient experiments with the HadGEM3-GC2 coupled model were designed to isolate the impact of Asian anthropogenic aeros...
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ftcopernicus:oai:publications.copernicus.org:acp71535 2023-05-15T17:34:22+02:00 Mechanisms for a remote response to Asian anthropogenic aerosol in boreal winter Wilcox, Laura J. Dunstone, Nick Lewinschal, Anna Bollasina, Massimo Ekman, Annica M. L. Highwood, Eleanor J. 2019-07-17 application/pdf https://doi.org/10.5194/acp-19-9081-2019 https://www.atmos-chem-phys.net/19/9081/2019/ eng eng doi:10.5194/acp-19-9081-2019 https://www.atmos-chem-phys.net/19/9081/2019/ eISSN: 1680-7324 Text 2019 ftcopernicus https://doi.org/10.5194/acp-19-9081-2019 2019-12-24T09:48:49Z Asian emissions of anthropogenic aerosols and their precursors have increased rapidly since 1980, with half of the increase since the pre-industrial era occurring in this period. Transient experiments with the HadGEM3-GC2 coupled model were designed to isolate the impact of Asian anthropogenic aerosols on global climate in boreal winter. It is found that this increase has resulted in local circulation changes, which in turn have driven decreases in precipitation over China, alongside an intensification of the offshore monsoon flow. No large temperature changes are seen over China. Over India, the opposite response is found, with decreasing temperatures and increasing precipitation. The dominant feature of the local circulation changes is an increase in low-level convergence, ascent, and precipitation over the Maritime Continent, which forms part of a tropical Pacific-wide La Niña-like response. HadGEM3-GC2 also simulates pronounced far-field responses. A decreased meridional temperature gradient in the North Pacific leads to a positive Pacific–North American circulation pattern, with associated temperature anomalies over the North Pacific and North America. Anomalous northeasterly flow over northeast Europe drives advection of cold air into central and western Europe, causing cooling in this region. An anomalous anticyclonic circulation over the North Atlantic causes drying over western Europe. Using a steady-state primitive equation model, LUMA, we demonstrate that these far-field midlatitude responses arise primarily as a result of Rossby waves generated over China, rather than in the equatorial Pacific. Text North Atlantic Copernicus Publications: E-Journals Pacific Atmospheric Chemistry and Physics 19 14 9081 9095 |
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English |
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Asian emissions of anthropogenic aerosols and their precursors have increased rapidly since 1980, with half of the increase since the pre-industrial era occurring in this period. Transient experiments with the HadGEM3-GC2 coupled model were designed to isolate the impact of Asian anthropogenic aerosols on global climate in boreal winter. It is found that this increase has resulted in local circulation changes, which in turn have driven decreases in precipitation over China, alongside an intensification of the offshore monsoon flow. No large temperature changes are seen over China. Over India, the opposite response is found, with decreasing temperatures and increasing precipitation. The dominant feature of the local circulation changes is an increase in low-level convergence, ascent, and precipitation over the Maritime Continent, which forms part of a tropical Pacific-wide La Niña-like response. HadGEM3-GC2 also simulates pronounced far-field responses. A decreased meridional temperature gradient in the North Pacific leads to a positive Pacific–North American circulation pattern, with associated temperature anomalies over the North Pacific and North America. Anomalous northeasterly flow over northeast Europe drives advection of cold air into central and western Europe, causing cooling in this region. An anomalous anticyclonic circulation over the North Atlantic causes drying over western Europe. Using a steady-state primitive equation model, LUMA, we demonstrate that these far-field midlatitude responses arise primarily as a result of Rossby waves generated over China, rather than in the equatorial Pacific. |
format |
Text |
author |
Wilcox, Laura J. Dunstone, Nick Lewinschal, Anna Bollasina, Massimo Ekman, Annica M. L. Highwood, Eleanor J. |
spellingShingle |
Wilcox, Laura J. Dunstone, Nick Lewinschal, Anna Bollasina, Massimo Ekman, Annica M. L. Highwood, Eleanor J. Mechanisms for a remote response to Asian anthropogenic aerosol in boreal winter |
author_facet |
Wilcox, Laura J. Dunstone, Nick Lewinschal, Anna Bollasina, Massimo Ekman, Annica M. L. Highwood, Eleanor J. |
author_sort |
Wilcox, Laura J. |
title |
Mechanisms for a remote response to Asian anthropogenic aerosol in boreal winter |
title_short |
Mechanisms for a remote response to Asian anthropogenic aerosol in boreal winter |
title_full |
Mechanisms for a remote response to Asian anthropogenic aerosol in boreal winter |
title_fullStr |
Mechanisms for a remote response to Asian anthropogenic aerosol in boreal winter |
title_full_unstemmed |
Mechanisms for a remote response to Asian anthropogenic aerosol in boreal winter |
title_sort |
mechanisms for a remote response to asian anthropogenic aerosol in boreal winter |
publishDate |
2019 |
url |
https://doi.org/10.5194/acp-19-9081-2019 https://www.atmos-chem-phys.net/19/9081/2019/ |
geographic |
Pacific |
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Pacific |
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North Atlantic |
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North Atlantic |
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eISSN: 1680-7324 |
op_relation |
doi:10.5194/acp-19-9081-2019 https://www.atmos-chem-phys.net/19/9081/2019/ |
op_doi |
https://doi.org/10.5194/acp-19-9081-2019 |
container_title |
Atmospheric Chemistry and Physics |
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19 |
container_issue |
14 |
container_start_page |
9081 |
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9095 |
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1766133170019762176 |