What controls the recent changes in African mineral dust aerosol across the Atlantic?
Dust from Africa strongly perturbs the radiative balance over the Atlantic, with emissions that are highly variable from year to year. We show that the aerosol optical depth (AOD) of dust over the mid-Atlantic observed by the AVHRR satellite has decreased by approximately 10% per decade from 1982 to...
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ftnonlinearchiv:oai:noa.gwlb.de:cop_mods_00044988 2023-05-15T17:35:31+02:00 What controls the recent changes in African mineral dust aerosol across the Atlantic? Ridley, D. A. Heald, C. L. Prospero, J. M. 2014-06 electronic https://doi.org/10.5194/acp-14-5735-2014 https://noa.gwlb.de/receive/cop_mods_00044988 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00044608/acp-14-5735-2014.pdf https://acp.copernicus.org/articles/14/5735/2014/acp-14-5735-2014.pdf eng eng Copernicus Publications Atmospheric Chemistry and Physics -- http://www.atmos-chem-phys.net/volumes_and_issues.html -- http://www.bibliothek.uni-regensburg.de/ezeit/?2069847 -- 1680-7324 https://doi.org/10.5194/acp-14-5735-2014 https://noa.gwlb.de/receive/cop_mods_00044988 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00044608/acp-14-5735-2014.pdf https://acp.copernicus.org/articles/14/5735/2014/acp-14-5735-2014.pdf uneingeschränkt info:eu-repo/semantics/openAccess article Verlagsveröffentlichung article Text doc-type:article 2014 ftnonlinearchiv https://doi.org/10.5194/acp-14-5735-2014 2022-02-08T22:39:48Z Dust from Africa strongly perturbs the radiative balance over the Atlantic, with emissions that are highly variable from year to year. We show that the aerosol optical depth (AOD) of dust over the mid-Atlantic observed by the AVHRR satellite has decreased by approximately 10% per decade from 1982 to 2008. This downward trend persists through both winter and summer close to source and is also observed in dust surface concentration measurements downwind in Barbados during summer. The GEOS-Chem model, driven with MERRA re-analysis meteorology and using a new dust source activation scheme, reproduces the observed trend and is used to quantify the factors contributing to this trend and the observed variability from 1982 to 2008. We find that changes in dustiness over the east mid-Atlantic are almost entirely mediated by a reduction in surface winds over dust source regions in Africa and are not directly linked with changes in land use or vegetation cover. The global mean all-sky direct radiative effect (DRE) of African dust is −0.18 Wm−2 at top of atmosphere, accounting for 46% of the global dust total, with a regional DRE of −7.4 ± 1.5 Wm−2 at the surface of the mid-Atlantic, varying by over 6.0 Wm−2 from year to year, with a trend of +1.3 Wm−2 per decade. These large interannual changes and the downward trend highlight the importance of climate feedbacks on natural aerosol abundance. Our analysis of the CMIP5 models suggests that the decreases in the indirect anthropogenic aerosol forcing over the North Atlantic in recent decades may be responsible for the observed climate response in African dust, indicating a potential amplification of anthropogenic aerosol radiative impacts in the Atlantic via natural mineral dust aerosol. Article in Journal/Newspaper North Atlantic Niedersächsisches Online-Archiv NOA Merra ENVELOPE(12.615,12.615,65.816,65.816) Atmospheric Chemistry and Physics 14 11 5735 5747 |
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article Verlagsveröffentlichung |
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article Verlagsveröffentlichung Ridley, D. A. Heald, C. L. Prospero, J. M. What controls the recent changes in African mineral dust aerosol across the Atlantic? |
topic_facet |
article Verlagsveröffentlichung |
description |
Dust from Africa strongly perturbs the radiative balance over the Atlantic, with emissions that are highly variable from year to year. We show that the aerosol optical depth (AOD) of dust over the mid-Atlantic observed by the AVHRR satellite has decreased by approximately 10% per decade from 1982 to 2008. This downward trend persists through both winter and summer close to source and is also observed in dust surface concentration measurements downwind in Barbados during summer. The GEOS-Chem model, driven with MERRA re-analysis meteorology and using a new dust source activation scheme, reproduces the observed trend and is used to quantify the factors contributing to this trend and the observed variability from 1982 to 2008. We find that changes in dustiness over the east mid-Atlantic are almost entirely mediated by a reduction in surface winds over dust source regions in Africa and are not directly linked with changes in land use or vegetation cover. The global mean all-sky direct radiative effect (DRE) of African dust is −0.18 Wm−2 at top of atmosphere, accounting for 46% of the global dust total, with a regional DRE of −7.4 ± 1.5 Wm−2 at the surface of the mid-Atlantic, varying by over 6.0 Wm−2 from year to year, with a trend of +1.3 Wm−2 per decade. These large interannual changes and the downward trend highlight the importance of climate feedbacks on natural aerosol abundance. Our analysis of the CMIP5 models suggests that the decreases in the indirect anthropogenic aerosol forcing over the North Atlantic in recent decades may be responsible for the observed climate response in African dust, indicating a potential amplification of anthropogenic aerosol radiative impacts in the Atlantic via natural mineral dust aerosol. |
format |
Article in Journal/Newspaper |
author |
Ridley, D. A. Heald, C. L. Prospero, J. M. |
author_facet |
Ridley, D. A. Heald, C. L. Prospero, J. M. |
author_sort |
Ridley, D. A. |
title |
What controls the recent changes in African mineral dust aerosol across the Atlantic? |
title_short |
What controls the recent changes in African mineral dust aerosol across the Atlantic? |
title_full |
What controls the recent changes in African mineral dust aerosol across the Atlantic? |
title_fullStr |
What controls the recent changes in African mineral dust aerosol across the Atlantic? |
title_full_unstemmed |
What controls the recent changes in African mineral dust aerosol across the Atlantic? |
title_sort |
what controls the recent changes in african mineral dust aerosol across the atlantic? |
publisher |
Copernicus Publications |
publishDate |
2014 |
url |
https://doi.org/10.5194/acp-14-5735-2014 https://noa.gwlb.de/receive/cop_mods_00044988 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00044608/acp-14-5735-2014.pdf https://acp.copernicus.org/articles/14/5735/2014/acp-14-5735-2014.pdf |
long_lat |
ENVELOPE(12.615,12.615,65.816,65.816) |
geographic |
Merra |
geographic_facet |
Merra |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_relation |
Atmospheric Chemistry and Physics -- http://www.atmos-chem-phys.net/volumes_and_issues.html -- http://www.bibliothek.uni-regensburg.de/ezeit/?2069847 -- 1680-7324 https://doi.org/10.5194/acp-14-5735-2014 https://noa.gwlb.de/receive/cop_mods_00044988 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00044608/acp-14-5735-2014.pdf https://acp.copernicus.org/articles/14/5735/2014/acp-14-5735-2014.pdf |
op_rights |
uneingeschränkt info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.5194/acp-14-5735-2014 |
container_title |
Atmospheric Chemistry and Physics |
container_volume |
14 |
container_issue |
11 |
container_start_page |
5735 |
op_container_end_page |
5747 |
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1766134697307406336 |