noaa-ocean-20775 Saharan dust fluxes over the last 22 ka in the Bahamas and central tropical Atlantic Williams, R.H.; McGee, D.; Kinsley, C.W.; Ridley, D.A.; Hu, S.; Fedorov, A.V.; Tal, I.; Murray, R.W.; deMenocal, P.B. Saharan dust fluxes over the last 22 ka in the Bahamas and central tropical Atlantic 2016-11-16 NCDC-Paleoclimatology ONLINE Files Pending https://www.ncdc.noaa.gov/paleo/study/20775 Investigator R.H. Williams Investigator D. McGee Investigator C.W. Kinsley Investigator D.A. Ridley Investigator S. Hu Investigator A.V. Fedorov Investigator I. Tal Investigator R.W. Murray Investigator P.B. deMenocal earth science paleoclimate paleoceanography 232Th,sediment,null,disintegration per minute per gram,null,paleoceanography,null,inductively-coupled plasma mass spectrometry,N,detrital sediment earth science paleoclimate paleoceanography 232Th,sediment,one standard deviation,disintegration per minute per gram,null,paleoceanography,null,inductively-coupled plasma mass spectrometry,N,detrital sediment earth science paleoclimate paleoceanography age,null,null,calendar kiloyear before present,null,paleoceanography,null,null,N,null earth science paleoclimate paleoceanography 230Th,sediment,one standard deviation,gram per square centimeter per kiloyear,null,paleoceanography,null,inductively-coupled plasma mass spectrometry,N,230Th normalized sediment flux earth science paleoclimate paleoceanography dust,null,null,gram per square centimeter per kiloyear,null,paleoceanography,null,null,N,dust flux; assumes 232Th concentration of 13.7 ± 1.0 µg/g in dust earth science paleoclimate paleoceanography dust,null,one standard deviation,gram per square centimeter per kiloyear,null,paleoceanography,null,null,N,dust flux earth science paleoclimate paleoceanography notes,null,null,null,null,paleoceanography,null,null,C,Core earth science paleoclimate paleoceanography 230Th,sediment,null,disintegration per minute per gram,null,paleoceanography,null,inductively-coupled plasma mass spectrometry,N,detrital sediment earth science paleoclimate paleoceanography depth,null,null,meter,null,paleoceanography,null,null,N,depth of water column earth science paleoclimate paleoceanography 230Th,sediment,one standard deviation,disintegration per minute per gram,null,paleoceanography,null,inductively-coupled plasma mass spectrometry,N,detrital sediment earth science paleoclimate paleoceanography 238U,sediment,one standard deviation,disintegration per minute per gram,null,paleoceanography,null,inductively-coupled plasma mass spectrometry,N,detrital sediment earth science paleoclimate paleoceanography zircon,sediment,null,microgram per gram,null,paleoceanography,null,inductively-coupled plasma mass spectrometry,N,detrital sediment earth science paleoclimate paleoceanography depth at sample start,null,null,centimeter,null,paleoceanography,null,null,N,null earth science paleoclimate paleoceanography thorium,sediment,null,microgram per gram,null,paleoceanography,null,inductively-coupled plasma mass spectrometry,N,detrital sediment earth science paleoclimate paleoceanography notes,null,null,null,null,paleoceanography,null,null,C,core ID earth science paleoclimate paleoceanography 230Th,sediment,null,gram per square centimeter per kiloyear,null,paleoceanography,null,inductively-coupled plasma mass spectrometry,N,230Th normalized sediment flux; assumes detrital U/Th activity ratio of 0.6 ± 0.1 earth science paleoclimate paleoceanography 232Th,sediment,null,microgram per gram,null,paleoceanography,null,inductively-coupled plasma mass spectrometry,N,detrital sediment earth science paleoclimate paleoceanography depth,null,null,centimeter,null,paleoceanography,null,null,N,null earth science paleoclimate paleoceanography 238U,sediment,null,disintegration per minute per gram,null,paleoceanography,null,inductively-coupled plasma mass spectrometry,N,detrital sediment earth science paleoclimate paleoceanography depth at sample end,null,null,centimeter,null,paleoceanography,null,null,N,null earth science paleoclimate paleoceanography scandium,sediment,null,microgram per gram,null,paleoceanography,null,inductively-coupled plasma mass spectrometry,N,detrital sediment earth science paleoclimate paleocean geochemistry earth science paleoclimate paleocean lithology earth science paleoclimate paleocean radiogenic isotope geoscientificInformation 22248 cal yr BP 288 cal yr BP Complete 5.33 26.0703 -78.05617 -33.03 Ocean Atlantic Ocean North Atlantic Ocean Caribbean Sea Bahamas OCE205-2 100GGC and 103GGC>LATITUDE 26.065>LONGITUDE -78.041 Ocean Atlantic Ocean VM20-234>LATITUDE 5.33>LONGITUDE -33.03 None Please cite original publication, online resource, dataset and publication DOIs (where available), and date accessed when using downloaded data. If there is no publication information, please cite investigator, title, online resource, and date accessed. The appearance of external links associated with a dataset does not constitute endorsement by the Department of Commerce/National Oceanic and Atmospheric Administration of external Web sites or the information, products or services contained therein. For other than authorized activities, the Department of Commerce/NOAA does not exercise any editorial control over the information you may find at these locations. These links are provided consistent with the stated purpose of this Department of Commerce/NOAA Web site. English DOC/NOAA/NESDIS/NCEI National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce https://www.ncdc.noaa.gov/data-access/paleoclimatology-data DATA Center Contact Bruce Bauer bruce.a.bauer@noaa.gov paleo@noaa.gov 303-497-6280 303-497-6513

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Boulder CO 80305-3328 USA online ASCII Williams, R.H., D. McGee, D.A. Ridley, C.W. Kinsley, S. Hu, A. Fedorov, I. Tal, R. Murray, and P.B. deMenocal 2016 Science Advances 2 10.1126/sciadv.1600445

Saharan mineral dust exported over the tropical North Atlantic is thought to have significant impacts on regional climate and ecosystems, but limited data exists 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 early Holocene, when climate models consistently underestimate the intensification of the West African monsoon documented by paleorecords. Here 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 Holocene dust fluxes 40-50% lower than recent values and maximum dust fluxes during the deglaciation, demonstrating strong 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. STUDY NOTES: Provided Keywords: Saharan dust; Bahamas; North Atlantic; Th-normalization; Last Glacial Maximum; African Humid Period; Holocene

GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/williams2016/williams2016-100-103ggc-geochem.txt Formatted Text File; OCE205-2 100GGC and 103GGC Geochemistry Data GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/williams2016/williams2016-vm20-234.txt Formatted Text File; VM20-234 Radiogenic Isotope and Dust Flux Data GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/williams2016/williams2016-100-103ggc-iso.txt Formatted Text File; OCE205-2 100GGC and 103GGC Radiogenic Isotope and Dust Flux Data USA/NOAA DIF Version 9.8.4 2018-12-11 2018-12-11