noaa-ocean-24890 Guaymas Basin 9-12kYrBP Leaf Wax Isotopes and Precipitation Reconstructions Bhattacharya, T.; Tierney, J.E.; Addison, J.A.; Murray, J.W. Guaymas Basin 9-12kYrBP Leaf Wax Isotopes and Precipitation Reconstructions 2018-09-03 NCDC-Paleoclimatology ONLINE Files Pending https://www.ncdc.noaa.gov/paleo/study/24890 Investigator T. Bhattacharya Investigator J.E. Tierney Investigator J.A. Addison Investigator J.W. Murray earth science paleoclimate paleoceanography delta 2H,C30 n-alkanoic acid,null,per mil VSMOW,null,paleoceanography,corrected,gas chromatography|isotope ratio mass spectrometry,N,corrected for ice volume earth science paleoclimate paleoceanography delta 2H,C30 n-alkanoic acid,null,per mil VSMOW,null,paleoceanography,null,gas chromatography|isotope ratio mass spectrometry,N,null earth science paleoclimate paleoceanography delta 13C,C30 n-alkanoic acid,null,per mil VSMOW,null,paleoceanography,null,gas chromatography|isotope ratio mass spectrometry,N,null earth science paleoclimate paleoceanography delta 2H,C30 n-alkanoic acid,null,per mil VSMOW,null,paleoceanography,null,gas chromatography|isotope ratio mass spectrometry,N,corrected for ice volume earth science paleoclimate climate reconstructions|paleoceanography depth,null,null,centimeter,null,climate reconstructions|paleoceanography,null,null,N,null earth science paleoclimate climate reconstructions|paleoceanography precipitation,delta 2H,unspecified margin of error,percent,Jul-Sep,climate reconstructions|paleoceanography,null,Bayesian inference,N,error for Mean percent July-September rainfall earth science paleoclimate climate reconstructions|paleoceanography precipitation,delta 2H,null,percent,Jul-Sep,climate reconstructions|paleoceanography,null,Bayesian inference,N,Mean percent July-September rainfall earth science paleoclimate climate reconstructions|paleoceanography age,null,null,calendar year before present,null,climate reconstructions|paleoceanography,null,null,N,null earth science paleoclimate paleocean biomarkers earth science paleoclimate paleocean carbon isotopes geoscientificInformation Monsoon 24266 cal yr BP 1460 cal yr BP Complete 22.23 27.4835 -112.1 -107.05 -1018 -881 Ocean Pacific Ocean Eastern Pacific Ocean NH-8P>LATITUDE 22.23>LONGITUDE -107.05 Ocean Atlantic Ocean North Atlantic Ocean Gulf Of Mexico MD02-2515>LATITUDE 27.4835>LONGITUDE -112.0743 Ocean Pacific Ocean Eastern Pacific Ocean MD02-2517>LATITUDE 27.48>LONGITUDE -112.07 Ocean Pacific Ocean Eastern Pacific Ocean JPC-56>LATITUDE 27.47>LONGITUDE -112.1 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 Tripti Bhattacharya, Jessica E. Tierney, Jason A. Addison, James W. Murray 2018 Nature Geoscience 10.1038/s41561-018-0220-7 https://www.nature.com/articles/s41561-018-0220-7

The North American monsoon, the dominant source of rainfall for much of the arid US Southwest, remains one of the least understood monsoon systems. The late Pleistocene evolution of this monsoon is poorly constrained, largely because glacial changes in winter rainfall obscure summer monsoon signatures in many regional proxy records. Here, we develop deglacial records of monsoon strength from isotopic analyses of leaf wax biomarkers in marine sediment cores. Reconstructions indicate a regional decrease in monsoon rainfall during the Last Glacial Maximum, and that the deglacial trajectory of the North American monsoon closely tracks changes in North American ice cover. In climate model simulations, North American ice cover shifts the westerlies southwards, favouring the mixing of cold, dry air into the US Southwest. This process, known as ventilation, weakens the monsoon by diluting the energy fluxes required for convection. As the ice sheet retreats northwards, the monsoon strengthens, and local ocean conditions may play a larger role in regulating its intensity. We conclude that on glacial-interglacial timescales, ice-sheet-induced reorganizations of atmospheric circulation have a dominant influence on the North American monsoon. STUDY NOTES: Stable isotope (dD and d13C) data on leaf waxes, plus summer (July-September) monsoon precipitation percent reconstructions from 4 sediment cores collected in the Guaymas Basin, Gulf of California, for the interval 9-12 kYrBP.

GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/bhattacharya2018/bhattacharya2018md022515.txt NOAA Template File; Core MD02-2515 Leaf Wax Stable Isotope Data and Monsoon Precipitation GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/bhattacharya2018/bhattacharya2018jpc56.txt NOAA Template File; Core JPC-56 Leaf Wax Stable Isotope Data and Monsoon Precipitation GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/bhattacharya2018/bhattacharya2018md022517.txt NOAA Template File; Core MD02-2517 Leaf Wax Stable Isotope Data and Monsoon Precipitation GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/bhattacharya2018/bhattacharya2018nh-8p.txt NOAA Template File; Core NH-8P Leaf Wax Stable Isotope Data and Monsoon Precipitation USA/NOAA DIF Version 9.8.4 2018-12-11 2018-12-11