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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| Format: | Article |
| Language: | en_US |
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American Association for the Advancement of Science (AAAS)
2017
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| Online Access: | http://hdl.handle.net/1721.1/108486 https://orcid.org/0000-0002-3819-4926 https://orcid.org/0000-0002-3185-520X https://orcid.org/0000-0003-3890-0197 |
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| author | Hu, S. Fedorov, A. Murray, R. W. deMenocal, P. B. Williams, Ross Hamilton McGee, William David Kinsley, Christopher William Ridley, David Andrew Tal, Irit |
| author2 | Joint Program in Oceanography/Applied Ocean Science and Engineering |
| author_facet | Joint Program in Oceanography/Applied Ocean Science and Engineering Hu, S. Fedorov, A. Murray, R. W. deMenocal, P. B. Williams, Ross Hamilton McGee, William David Kinsley, Christopher William Ridley, David Andrew Tal, Irit |
| author_sort | Hu, S. |
| collection | MIT |
| 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. |
| first_indexed | 2024-09-23T12:36:12Z |
| format | Article |
| id | mit-1721.1/108486 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T12:36:12Z |
| publishDate | 2017 |
| publisher | American Association for the Advancement of Science (AAAS) |
| record_format | dspace |
| spelling | mit-1721.1/1084862022-09-28T08:57:30Z Glacial to Holocene changes in trans-Atlantic Saharan dust transport and dust-climate feedbacks Hu, S. Fedorov, A. Murray, R. W. deMenocal, P. B. Williams, Ross Hamilton McGee, William David Kinsley, Christopher William Ridley, David Andrew Tal, Irit Joint Program in Oceanography/Applied Ocean Science and Engineering Massachusetts Institute of Technology. Department of Civil and Environmental Engineering Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences Woods Hole Oceanographic Institution Williams, Ross Hamilton McGee, William David Kinsley, Christopher William Ridley, David Andrew Tal, Irit 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. National Science Foundation (U.S.) (Award OCE-1030784) United States. National Aeronautics and Space Administration (Grant NN14AP38G) Columbia University. Center for Climate and Life 2017-04-28T14:08:47Z 2017-04-28T14:08:47Z 2016-11 2016-02 Article http://purl.org/eprint/type/JournalArticle 2375-2548 http://hdl.handle.net/1721.1/108486 Williams, R. H. et al. “Glacial to Holocene Changes in Trans-Atlantic Saharan Dust Transport and Dust-Climate Feedbacks.” Science Advances 2.11 (2016): e1600445–e1600445. https://orcid.org/0000-0002-3819-4926 https://orcid.org/0000-0002-3185-520X https://orcid.org/0000-0003-3890-0197 en_US http://dx.doi.org/10.1126/sciadv.1600445 Science Advances Creative Commons Attribution-NonCommercial 4.0 International http://creativecommons.org/licenses/by-nc/4.0/ application/pdf American Association for the Advancement of Science (AAAS) AAAS |
| spellingShingle | Hu, S. Fedorov, A. Murray, R. W. deMenocal, P. B. Williams, Ross Hamilton McGee, William David Kinsley, Christopher William Ridley, David Andrew Tal, Irit Glacial to Holocene changes in trans-Atlantic Saharan dust transport and dust-climate feedbacks |
| title | 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_short | 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 |
| url | http://hdl.handle.net/1721.1/108486 https://orcid.org/0000-0002-3819-4926 https://orcid.org/0000-0002-3185-520X https://orcid.org/0000-0003-3890-0197 |
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