Hemispheric-wide climate response to regional COVID-19-related aerosol emission reductions: the prominent role of atmospheric circulation adjustments
The national and global restrictions in response to the COVID-19 pandemic led to a sudden, albeit temporary, emission reduction of many greenhouse gases (GHGs) and anthropogenic aerosols, whose near-term climate impact was previously found to be negligible when focusing on global- and/or annual-mean...
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ftcopernicus:oai:publications.copernicus.org:acpd105767 2023-05-15T13:15:06+02:00 Hemispheric-wide climate response to regional COVID-19-related aerosol emission reductions: the prominent role of atmospheric circulation adjustments Fahrenbach, Nora Lea Sophie Bollasina, Massimo Alberto 2022-09-26 application/pdf https://doi.org/10.5194/acp-2022-558 https://acp.copernicus.org/preprints/acp-2022-558/ eng eng doi:10.5194/acp-2022-558 https://acp.copernicus.org/preprints/acp-2022-558/ eISSN: 1680-7324 Text 2022 ftcopernicus https://doi.org/10.5194/acp-2022-558 2022-10-03T16:22:43Z The national and global restrictions in response to the COVID-19 pandemic led to a sudden, albeit temporary, emission reduction of many greenhouse gases (GHGs) and anthropogenic aerosols, whose near-term climate impact was previously found to be negligible when focusing on global- and/or annual-mean scales. Our study aims to investigate the monthly-scale coupled climate and circulation response to regional, COVID-19-related aerosol emission reductions, using the output from ten Earth System Models participating in the Covid Model Intercomparison Project (CovidMIP). We focus on January–February and March–May 2020, which represent the seasons of largest emission changes in sulphate (SO 2 ) and black carbon (BC). During JF, a marked decrease in aerosol emissions over eastern China, the main emission region, results in a lower aerosol burden, leading to an increase in surface downwelling radiation and ensuing surface warming. Regional sea-level pressure and circulation adjustments drive a precipitation increase over the Maritime Continent, embedded in a negative PDO/ENSO-like response over the Pacific, in turn associated with a northwestward displacement and zonal shrinking of the Indo-Pacific Walker cell. Remote climate anomalies across the Northern Hemisphere, including a weakening of the Siberian High and Aleutian Low as well as anomalous temperature patterns in the northern mid-latitudes, arise primarily as a result of stationary Rossby wave trains generated over East Asia. The anomalous climate pattern and driving dynamical mechanism reverse polarity between JF and MAM 2020, which is shown to be consistent with an underlying shift of the dominant region of SO 2 emission reduction from eastern China in JF to India in MAM. Our findings highlight the prominent role of large-scale dynamical adjustments in generating a hemispheric-wide aerosol climate imprint even on short time scales, which are largely consistent with longer-term (decadal) trends. Furthermore, our analysis shows the sensitivity of the climate ... Text aleutian low Copernicus Publications: E-Journals Pacific |
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Copernicus Publications: E-Journals |
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The national and global restrictions in response to the COVID-19 pandemic led to a sudden, albeit temporary, emission reduction of many greenhouse gases (GHGs) and anthropogenic aerosols, whose near-term climate impact was previously found to be negligible when focusing on global- and/or annual-mean scales. Our study aims to investigate the monthly-scale coupled climate and circulation response to regional, COVID-19-related aerosol emission reductions, using the output from ten Earth System Models participating in the Covid Model Intercomparison Project (CovidMIP). We focus on January–February and March–May 2020, which represent the seasons of largest emission changes in sulphate (SO 2 ) and black carbon (BC). During JF, a marked decrease in aerosol emissions over eastern China, the main emission region, results in a lower aerosol burden, leading to an increase in surface downwelling radiation and ensuing surface warming. Regional sea-level pressure and circulation adjustments drive a precipitation increase over the Maritime Continent, embedded in a negative PDO/ENSO-like response over the Pacific, in turn associated with a northwestward displacement and zonal shrinking of the Indo-Pacific Walker cell. Remote climate anomalies across the Northern Hemisphere, including a weakening of the Siberian High and Aleutian Low as well as anomalous temperature patterns in the northern mid-latitudes, arise primarily as a result of stationary Rossby wave trains generated over East Asia. The anomalous climate pattern and driving dynamical mechanism reverse polarity between JF and MAM 2020, which is shown to be consistent with an underlying shift of the dominant region of SO 2 emission reduction from eastern China in JF to India in MAM. Our findings highlight the prominent role of large-scale dynamical adjustments in generating a hemispheric-wide aerosol climate imprint even on short time scales, which are largely consistent with longer-term (decadal) trends. Furthermore, our analysis shows the sensitivity of the climate ... |
format |
Text |
author |
Fahrenbach, Nora Lea Sophie Bollasina, Massimo Alberto |
spellingShingle |
Fahrenbach, Nora Lea Sophie Bollasina, Massimo Alberto Hemispheric-wide climate response to regional COVID-19-related aerosol emission reductions: the prominent role of atmospheric circulation adjustments |
author_facet |
Fahrenbach, Nora Lea Sophie Bollasina, Massimo Alberto |
author_sort |
Fahrenbach, Nora Lea Sophie |
title |
Hemispheric-wide climate response to regional COVID-19-related aerosol emission reductions: the prominent role of atmospheric circulation adjustments |
title_short |
Hemispheric-wide climate response to regional COVID-19-related aerosol emission reductions: the prominent role of atmospheric circulation adjustments |
title_full |
Hemispheric-wide climate response to regional COVID-19-related aerosol emission reductions: the prominent role of atmospheric circulation adjustments |
title_fullStr |
Hemispheric-wide climate response to regional COVID-19-related aerosol emission reductions: the prominent role of atmospheric circulation adjustments |
title_full_unstemmed |
Hemispheric-wide climate response to regional COVID-19-related aerosol emission reductions: the prominent role of atmospheric circulation adjustments |
title_sort |
hemispheric-wide climate response to regional covid-19-related aerosol emission reductions: the prominent role of atmospheric circulation adjustments |
publishDate |
2022 |
url |
https://doi.org/10.5194/acp-2022-558 https://acp.copernicus.org/preprints/acp-2022-558/ |
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Pacific |
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Pacific |
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aleutian low |
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eISSN: 1680-7324 |
op_relation |
doi:10.5194/acp-2022-558 https://acp.copernicus.org/preprints/acp-2022-558/ |
op_doi |
https://doi.org/10.5194/acp-2022-558 |
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