noaa-ocean-16380 Tropical Atlantic Isotope, Chemistry and SST Data for the Last 27,000 Years Arbuszewski, J.A.; deMenocal, P.B.; Cleroux, C.; Bradtmiller, L.I.; Mix, A.C. Tropical Atlantic Isotope, Chemistry and SST Data for the Last 27,000 Years 2014-04-28 NCDC-Paleoclimatology ONLINE Files Pending https://www.ncdc.noaa.gov/paleo/study/16380 Investigator J.A. Arbuszewski Investigator P.B. deMenocal Investigator C. Cleroux Investigator L.I. Bradtmiller Investigator A.C. Mix earth science paleoclimate climate reconstructions|paleoceanography delta 18O,delta 18O|magnesium/calcium|sea water,null,per mil SMOW,null,climate reconstructions|paleoceanography,null,null,N,from Bemis et al.(1998) earth science paleoclimate climate reconstructions|paleoceanography sea surface temperature,magnesium/calcium,null,degree Celsius,null,climate reconstructions|paleoceanography,null,null,N,using Dekens et al.(2002); G. ruber white earth science paleoclimate paleoceanography magnesium/calcium,Globigerinoides ruber white,null,millimole per mole,null,paleoceanography,null,null,N,null earth science paleoclimate climate reconstructions|paleoceanography delta 18O,delta 18O|magnesium/calcium|sea water,null,per mil SMOW,null,climate reconstructions|paleoceanography,corrected,null,N,from Bemis et al.(1998); corrected for ice volume earth science paleoclimate paleoceanography age,null,null,calendar year before present,null,paleoceanography,null,null,N,null earth science paleoclimate paleoceanography delta 18O,Globigerinoides ruber white,null,per mil VPDB,null,paleoceanography,null,null,N,null earth science paleoclimate climate reconstructions|paleoceanography sea surface temperature,magnesium/calcium,null,degree Celsius,null,climate reconstructions|paleoceanography,null,null,N,using salinity and DeltaCO32- from Arbuszewski et al.(2010); G. ruber white earth science paleoclimate paleoceanography delta 18O,Globigerinoides ruber white,null,per mil VPDB,null,paleoceanography,corrected,null,N,ice volume corrected earth science paleoclimate climate reconstructions|paleoceanography salinity,delta 18O|magnesium/calcium|sea surface,null,parts per thousand,null,climate reconstructions|paleoceanography,null,null,N,calculated using Arbuszewski et al.(2010) earth science paleoclimate paleoceanography depth,null,null,centimeter,null,paleoceanography,null,null,N,null earth science paleoclimate paleocean geochemistry earth science paleoclimate paleocean oxygen isotopes earth science paleoclimate paleocean reconstruction geoscientificInformation Intertropical Convergence Zone (ITCZ) Sea Surface Temperature Reconstruction 27667 cal yr BP 1890 cal yr BP Complete -2.18 1.367 -33.483 -11.25 -3882 -3445 Ocean Atlantic Ocean VM25-59>LATITUDE 1.367>LONGITUDE -33.483 Ocean Atlantic Ocean RC24-08>LATITUDE -1.3366>LONGITUDE -11.9 Ocean Atlantic Ocean RC24-11>LATITUDE -2.18>LONGITUDE -11.25 Ocean Atlantic Ocean VM30-40>LATITUDE -.2>LONGITUDE -23.15 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 Arbuszewski, J.A., P.B. deMenocal, C. Cleroux, L. Bradtmiller, and A. Mix 2013 Nature Geoscience 6 959-962 10.1038/ngeo1961

The intertropical convergence zone is a near-equatorial band of intense rainfall and convection. Over the modern Atlantic Ocean, its annual average position is approximately 5°N, and it is associated with low sea surface salinity and high surface temperatures. This average position has varied since the Last Glacial Maximum, in response to changing climate boundary conditions. The nature of this variation is less clear, with suggestions that the intertropical convergence zone migrated north-south away from the colder hemisphere or that it contracted and expanded symmetrically around its present position. Here we use paired Mg/Ca and d18O measurements of planktonic foraminifera for a transect of ocean sediment cores to reconstruct past changes in tropical surface ocean temperature and salinity in the Atlantic Ocean over the past 25,000 years. We show that the low-salinity, high-temperature surface waters associated with the intertropical convergence zone migrated southward of ! their present position during the Last Glacial Maximum, when the Northern Hemisphere cooled, and northward during the warmer early Holocene, by about ±7° degrees of latitude. Our evidence suggests that the intertropical convergence zone moved latitudinally over the ocean, rather than expanding or contracting. We conclude that the marine intertropical convergence zone has migrated significantly away from its present position owing to external climate forcing during the past 25,000 years. STUDY NOTES: Ice volume corrections to shell δ18O values are made using sea level curve of Waelbroeck et al. 2002. Note Mg/Ca ratios represent an average where replicate analyses were performed.

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