Little Ice Age climate and oceanic conditions of the Ross Se

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TitleLittle Ice Age climate and oceanic conditions of the Ross Sea, Antarctica from a coastal ice core recordAbstractIncreasing paleoclimatic evidence suggests that the Little Ice Age (LIA) was a global climate change event. Understanding the forcings and associated climate system feedbacks of the LIA is made difficult by the scarcity of Southern Hemisphere paleoclimate records. We use a new glaciochemical record of a coastal ice core from Mt. Erebus Saddle, Antarctica, to reconstruct atmospheric and oceanic conditions in the Ross Sea sector of Antarctica over the past five centuries. The LIA is identified in stable isotope (ÃŽv ZD) and lithophile element records, which respectively demonstrate that the region experienced 1.6 Ã‚Â± 1.4 Ã‚^circC cooler average temperatures prior to 1850 AD than during the last 150 yr and strong (>57 m s-1) prevailing katabatic winds between 1500 and 1800 AD. Al and Ti concentration increases of an order of magnitude (>120 ppb Al) are linked to enhanced aeolian transport of complex silicate minerals and represent the strongest katabatic wind events of the LIA. These events are associated with three 12-30 yr intervals of cooler temperatures at ca. 1690 AD, 1770 AD and 1840 AD. Furthermore, ice core concentrations of the biogenic sulphur species MS- suggest that biological productivity in the Ross Sea polynya was Â 80% higher prior to 1875 AD than at any subsequent time. We propose that cooler Antarctic temperatures promoted stronger katabatic winds across the Ross Ice Shelf, resulting in an enlarged Ross Sea polynya during the LIA. Copyright Author(s) 2012.AcknowledgementsWe sincerely thank Antarctica New Zealand, the US Polar Program, and Scott Base and McMurdo Station staff for logistical support. We thank the Alfred Wegener Institute for lending us the AWI ice core drill. Recovery of this ice core was made possible by Alex Pyne, Webster Drilling, Glenn and Tony Kingan, Ken Borek Ltd. and Helicopters New Zealand. Ground penetrating radar surveys were conducted by Matt Watson, ScanTec Ltd. Thanks to the staff of the Stable Isotope Laboratory, GNS Science, for their dedication to this work. Figure 7 was produced using a Matlab function available in the ``MATLAB Library for Robust AnalysisÂ" from the Katholieke Universiteit Leuven and the University of Antwerp (http://wis.kuleuven.be/stat/robust/Libra.html). This project is funded through the Marsden Fund (VUW0509) and the New Zealand Ministry for Science and Innovation via contracts awarded to Victoria University of Wellington and GNS Science (VICX0704 and CO5X0202). MES ice core data can be accessed at the iceREADER database http://icereader.org/icereader/.

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1st AuthorRhodes, R.AuthorRhodes, R.Bertler, N.Baker, J.Steen-Larsen, H.Sneed, S.Morgenstern, U.Johnsen, S.Year2012JournalClimate of the PastVolume8Number4Pages1223-1238DOI10.5194/cp-8-1223-2012Keywordsbiogenic materialbiological productionclimate feedbackclimate variationglaciochemistryglobal climateice coreLittle Ice Agepaleoceanographypaleoclimatereconstructionsulfur, AntarcticaRoss SeaSouthern Ocean, rank5

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TypeArticleCitationRhodes, R., Bertler, N., Baker, J., Steen-Larsen, H., Sneed, S., Morgenstern, U. and Johnsen, S. (2012) Little Ice Age climate and oceanic conditions of the Ross Sea, Antarctica from a coastal ice core record. Climate of the Past, 8(4): 1223-1238 doi:10.5194/cp-8-1223-2012IdentifierRhodes2012Relevancerank5