Eastern Tropical Indian Ocean 45,000 Year d18O and SST Reconstructions Mohtadi, M.; Prange, M.; Oppo, D.W.; De Pol-Holz, R.; Merkel, U.; Zhang, X.; Steinke, S.; Lückge, A. Mohtadi, M. Prange, M. Oppo, D.W. De Pol-Holz, R. Merkel, U. Zhang, X. Steinke, S. Lückge, A. Sea Surface Temperature Reconstruction 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,sea-level corrected after Waelbroeck et al. (2002); HL equation of 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,from Mg/Ca Globigerinoides ruber white sensu stricto; calculated after Anand et al. (2003)) earth science/paleoclimate/paleoceanography (age,null,null,calendar kiloyear before present,null,paleoceanography,null,null,N,null) earth science/paleoclimate/paleoceanography (delta 18O,Globigerinoides ruber sensu stricto,null,per mil PDB,null,paleoceanography,null,null,N,sensu stricto 250-355um; G. ruber white) earth science/paleoclimate/paleocean earth science/paleoclimate/paleocean (SO189-144KL>LATITUDE 1.15>LONGITUDE 98.0667) (SO189-39KL>LATITUDE -.7833>LONGITUDE 99.9) (SO189-119KL>LATITUDE 3.5167>LONGITUDE 96.3167) The response of the tropical climate in the Indian Ocean realm to abrupt climate change events in the North Atlantic Ocean is contentious. Repositioning of the intertropical convergence zone is thought to have been responsible for changes in tropical hydroclimate during North Atlantic cold spells, but the dearth of high-resolution records outside the monsoon realm in the Indian Ocean precludes a full understanding of this remote relationship and its underlying mechanisms. Here we show that slowdowns of the Atlantic meridional overturning circulation during Heinrich stadials and the Younger Dryas stadial affected the tropical Indian Ocean hydroclimate through changes to the Hadley circulation including a southward shift in the rising branch (the intertropical convergence zone) and an overall weakening over the southern Indian Ocean. Our results are based on new, high-resolution sea surface temperature and seawater oxygen isotope records of well-dated sedimentary archives from the tropical eastern Indian Ocean for the past 45,000 years, combined with climate model simulations of Atlantic circulation slowdown under Marine Isotope Stages 2 and 3 boundary conditions. Similar conditions in the east and west of the basin rule out a zonal dipole structure as the dominant forcing of the tropical Indian Ocean hydroclimate of millennial-scale events. Results from our simulations and proxy data suggest dry conditions in the northern Indian Ocean realm and wet and warm conditions in the southern realm during North Atlantic cold spells. STUDY NOTES: High-resolution (~30-80 years) foraminiferal oxygen isotope (d18O) data for the past 45,000 years, plus reconstructed sea-surface temperature and seawater d18O, from 3 eastern tropical Indian Ocean sediment cores. NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Mohtadi, M. Investigator : Prange, M. Investigator : Oppo, D.W. Investigator : De Pol-Holz, R. Investigator : Merkel, U. Investigator : Zhang, X. Investigator : Steinke, S. Investigator : Lückge, A. 2015-08-24 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/19139 https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/mohtadi2014/mohtadi2014-119kl.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/mohtadi2014/mohtadi2014-144kl.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/mohtadi2014/mohtadi2014-39kl.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/mohtadi2014/mohtadi2014-119kl.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/mohtadi2014/mohtadi2014-144kl.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/mohtadi2014/mohtadi2014-39kl.txt English https://www.ncdc.noaa.gov/paleo/study/19139 https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/mohtadi2014/mohtadi2014-119kl.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/mohtadi2014/mohtadi2014-144kl.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/mohtadi2014/mohtadi2014-39kl.txt Mahyar Mohtadi, Matthias Prange, Delia W. Oppo, Ricardo De Pol-Holz, Ute Merkel, Xiao Zhang, Stephan Steinke, Andreas Lückge2014North Atlantic forcing of tropical Indian Ocean climateNature509749876-8010.1038/nature13196http://www.nature.com/nature/journal/v509/n7498/full/nature13196.html START YEAR: 45330 cal yr BP * END YEAR: 60 cal yr BP 96.3167 -.7833 99.9 3.5167