Glacial to Holocene changes in trans-Atlantic Saharan dust transport and dust-climate feedbacks
Saharan mineral dust exported over the tropical North Atlantic is thought to have significant impacts on regional climate and ecosystems, but limited data exist documenting past changes in long-range dust transport. This data gap limits investigations of the role of Saharan dust in past climate chan...
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ftcolumbiauniv:oai:academiccommons.columbia.edu:10.7916/D8863P8K 2023-05-15T17:29:21+02:00 Glacial to Holocene changes in trans-Atlantic Saharan dust transport and dust-climate feedbacks Williams, Ross H. McGee, David Kinsley, Christopher W. Ridley, David A. Hu, Shineng Fedorov, Alexey Tal, Irit Murray, Richard W. deMenocal, Peter B. 2016 https://doi.org/10.7916/D8863P8K English eng https://doi.org/10.7916/D8863P8K Paleoclimatology Mineral dusts Ocean-atmosphere interaction Articles 2016 ftcolumbiauniv https://doi.org/10.7916/D8863P8K 2019-04-04T08:16:39Z Saharan mineral dust exported over the tropical North Atlantic is thought to have significant impacts on regional climate and ecosystems, but limited data exist documenting past changes in long-range dust transport. This data gap limits investigations of the role of Saharan dust in past climate change, in particular during the mid-Holocene, when climate models consistently underestimate the intensification of the West African monsoon documented by paleorecords. We present reconstructions of African dust deposition in sediments from the Bahamas and the tropical North Atlantic spanning the last 23,000 years. Both sites show early and mid-Holocene dust fluxes 40 to 50% lower than recent values and maximum dust fluxes during the deglaciation, demonstrating agreement with records from the northwest African margin. These quantitative estimates of trans-Atlantic dust transport offer important constraints on past changes in dust-related radiative and biogeochemical impacts. Using idealized climate model experiments to investigate the response to reductions in Saharan dust’s radiative forcing over the tropical North Atlantic, we find that small (0.15°C) dust-related increases in regional sea surface temperatures are sufficient to cause significant northward shifts in the Atlantic Intertropical Convergence Zone, increased precipitation in the western Sahel and Sahara, and reductions in easterly and northeasterly winds over dust source regions. Our results suggest that the amplifying feedback of dust on sea surface temperatures and regional climate may be significant and that accurate simulation of dust’s radiative effects is likely essential to improving model representations of past and future precipitation variations in North Africa. Article in Journal/Newspaper North Atlantic Columbia University: Academic Commons |
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Open Polar |
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Columbia University: Academic Commons |
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ftcolumbiauniv |
language |
English |
topic |
Paleoclimatology Mineral dusts Ocean-atmosphere interaction |
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Paleoclimatology Mineral dusts Ocean-atmosphere interaction Williams, Ross H. McGee, David Kinsley, Christopher W. Ridley, David A. Hu, Shineng Fedorov, Alexey Tal, Irit Murray, Richard W. deMenocal, Peter B. Glacial to Holocene changes in trans-Atlantic Saharan dust transport and dust-climate feedbacks |
topic_facet |
Paleoclimatology Mineral dusts Ocean-atmosphere interaction |
description |
Saharan mineral dust exported over the tropical North Atlantic is thought to have significant impacts on regional climate and ecosystems, but limited data exist documenting past changes in long-range dust transport. This data gap limits investigations of the role of Saharan dust in past climate change, in particular during the mid-Holocene, when climate models consistently underestimate the intensification of the West African monsoon documented by paleorecords. We present reconstructions of African dust deposition in sediments from the Bahamas and the tropical North Atlantic spanning the last 23,000 years. Both sites show early and mid-Holocene dust fluxes 40 to 50% lower than recent values and maximum dust fluxes during the deglaciation, demonstrating agreement with records from the northwest African margin. These quantitative estimates of trans-Atlantic dust transport offer important constraints on past changes in dust-related radiative and biogeochemical impacts. Using idealized climate model experiments to investigate the response to reductions in Saharan dust’s radiative forcing over the tropical North Atlantic, we find that small (0.15°C) dust-related increases in regional sea surface temperatures are sufficient to cause significant northward shifts in the Atlantic Intertropical Convergence Zone, increased precipitation in the western Sahel and Sahara, and reductions in easterly and northeasterly winds over dust source regions. Our results suggest that the amplifying feedback of dust on sea surface temperatures and regional climate may be significant and that accurate simulation of dust’s radiative effects is likely essential to improving model representations of past and future precipitation variations in North Africa. |
format |
Article in Journal/Newspaper |
author |
Williams, Ross H. McGee, David Kinsley, Christopher W. Ridley, David A. Hu, Shineng Fedorov, Alexey Tal, Irit Murray, Richard W. deMenocal, Peter B. |
author_facet |
Williams, Ross H. McGee, David Kinsley, Christopher W. Ridley, David A. Hu, Shineng Fedorov, Alexey Tal, Irit Murray, Richard W. deMenocal, Peter B. |
author_sort |
Williams, Ross H. |
title |
Glacial to Holocene changes in trans-Atlantic Saharan dust transport and dust-climate feedbacks |
title_short |
Glacial to Holocene changes in trans-Atlantic Saharan dust transport and dust-climate feedbacks |
title_full |
Glacial to Holocene changes in trans-Atlantic Saharan dust transport and dust-climate feedbacks |
title_fullStr |
Glacial to Holocene changes in trans-Atlantic Saharan dust transport and dust-climate feedbacks |
title_full_unstemmed |
Glacial to Holocene changes in trans-Atlantic Saharan dust transport and dust-climate feedbacks |
title_sort |
glacial to holocene changes in trans-atlantic saharan dust transport and dust-climate feedbacks |
publishDate |
2016 |
url |
https://doi.org/10.7916/D8863P8K |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_relation |
https://doi.org/10.7916/D8863P8K |
op_doi |
https://doi.org/10.7916/D8863P8K |
_version_ |
1766123261452615680 |