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Eastern tropical Pacific hydrologic changes during the past 27,000 years from D/H ratios in alkenones

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dc.contributor.author Pahnke, Katharina
dc.contributor.author Sachs, Julian P.
dc.contributor.author Keigwin, Lloyd D.
dc.contributor.author Timmermann, Axel
dc.contributor.author Xie, Shang-Ping
dc.date.accessioned 2010-05-13T19:20:22Z
dc.date.available 2010-05-13T19:20:22Z
dc.date.issued 2007-12-18
dc.identifier.citation Paleoceanography 22 (2007): PA4214 en_US
dc.identifier.uri http://hdl.handle.net/1912/3454
dc.description Author Posting. © American Geophysical Union, 2007. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Paleoceanography 22 (2007): PA4214, doi:10.1029/2007PA001468. en_US
dc.description.abstract The tropical Pacific plays a central role in the climate system by providing large diabatic heating that drives the global atmospheric circulation. Quantifying the role of the tropics in late Pleistocene climate change has been hampered by the paucity of paleoclimate records from this region and the lack of realistic transient climate model simulations covering this period. Here we present records of hydrogen isotope ratios (δD) of alkenones from the Panama Basin off the Colombian coast that document hydrologic changes in equatorial South America and the eastern tropical Pacific over the past 27,000 years (a) and the past 3 centuries in detail. Comparison of alkenone δD values with instrumental records of precipitation over the past ∼100 a suggests that δD can be used as a hydrologic proxy. On long timescales our records indicate reduced rainfall during the last glacial period that can be explained by a southward shift of the mean position of the Intertropical Convergence Zone and an associated reduction of Pacific moisture transport into Colombia. Precipitation increases at ∼17 ka in concert with sea surface temperature (SST) cooling in the North Atlantic and the eastern tropical Pacific. A regional coupled model, forced by negative SST anomalies in the Caribbean, simulates an intensification of northeasterly trade winds across Central America, increased evaporative cooling, and a band of increased rainfall in the northeastern tropical Pacific. These results are consistent with the alkenone SST and δD reconstructions that suggest increasing precipitation and SST cooling at the time of Heinrich event 1. en_US
dc.description.sponsorship K. P. and J. P. S. thank the Comer Science and Education Foundation for financial support. J. P. S. acknowledges support by the National Science Foundation (grant NSF-ESH-0639640). NSF grant OCE-0317702 funded cruise KNR176 to the Panama Basin and L. D. K.’s results presented here. A. T. is supported by the Japan Agency for Marine-Earth Science and Technology. S. P. X. is supported by the National Oceanic and Atmospheric Administration CLIVAR Program, the Japan Ministry of Education, Culture, Science and Technology through the Kyosei-7 Project, and the Japan Agency for Marine-Earth Science and Technology. en_US
dc.format.mimetype application/pdf
dc.language.iso en_US en_US
dc.publisher American Geophysical Union en_US
dc.relation.uri http://dx.doi.org/10.1029/2007PA001468
dc.subject Past hydrologic changes en_US
dc.subject Eastern tropical Pacific en_US
dc.subject Compound-specific hydrogen isotope ratios en_US
dc.title Eastern tropical Pacific hydrologic changes during the past 27,000 years from D/H ratios in alkenones en_US
dc.type Article en_US
dc.identifier.doi 10.1029/2007PA001468


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