Seasonality of airmass pathways to coastal Antarctica: Ramif

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TitleSeasonality of airmass pathways to coastal Antarctica: Ramifications for interpreting high-resolution ice core recordsAbstractUnderstanding airmass pathways is critical for ice core interpretation, and the ability to determine the broadscale characteristics and seasonality of synoptic-scale flow using paleoclimate records offers great potential to improve the understanding of past atmospheric circulation. The dominant airmass pathways to a coastal Antarctic ice core site at the Whitehall Glacier in the Ross Sea are modeled using snowfall and highresolution stable isotope data between 1979 and 2006, combined with back trajectories produced from both NCEP-NCAR and ECMWF Interim Re-Analysis (ERA-Interim) data. Back trajectories generated from both datasets produce comparable results. They show that high snowfall is associated with cyclonic airflow in the Ross Sea with a strong meridional component along the western Ross Sea coast. Over a 28-yr time frame, trajectories also reveal a clear distinction between flow paths associated with above- and below-average annual temperatures (high and low ÃŽv ZD) in the ice core record. In cold months (low ÃŽv ZD), when there is a strengthened trough of low pressure around the continent, synoptically driven incursions of marine air across West Antarctica and trajectories originating from coastal East Antarctica are dominant. Conversely, in warmer months (high δD), airmass pathways are centered over the Ross Sea and the adjacent Southern Ocean. These trajectories are slower moving and are expected to draw marine moisture from high-latitude seasonally open oceans. Copyright 2013 American Meteorological Society.AcknowledgementsThis project was funded by the New Zealand Ministry for Science and Innovation via contracts awarded to Victoria University of Wellington, GNS Science (VICX0704, CO5X0202, RDF-VUW1103) and a New Zealand Foundation for Research, Science and Technology Postdoctoral Fellowship (CO5X0902). We are grateful for logistical support for the ice core extraction (K049) by Antarctica New Zealand and the U.S. Polar Program and we thank the Alfred Wegener Institute for providing their shallow ice core drilling system. NCEP--NCAR reanalysis data were obtained from the NOAA Earth System Research Laboratory (http://www.esrl.noaa.gov/psd/data), and ERA-Interim data were downloaded from ECMWF (http://data.ecmwf.int/data). We thank two anonymous reviewers and Harold Sodemann for their constructive feedback on the draft manuscript. We are also grateful to Dougal Townsend and Richard Castillo for assistance with image processing.

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1st AuthorSinclair, K.AuthorSinclair, K.Bertler, N.Trompetter, W.Baisden, W.Year2013JournalJournal of ClimateVolume26Number6Pages2065-2076DOI10.1175/JCLI-D-12-00167.1KeywordsAnnual temperaturesAntarctic ice coreAtmospheric circulationBack trajectoriesEast antarcticaIce core recordsPaleoclimate recordsStable isotope data, ClimatologyDigital storageIsotopesSnowTrajectories, Ice, air massatmospheric circulationice corelow pressure systemmarine atmospherepaleoclimateseasonalitysynoptic meteorology, AntarcticaRoss SeaSouthern OceanWest Antarctica, rank5

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TypeArticleCitationSinclair, K., Bertler, N., Trompetter, W. and Baisden, W. (2013) Seasonality of airmass pathways to coastal Antarctica: Ramifications for interpreting high-resolution ice core records. Journal of Climate, 26(6): 2065-2076 doi:10.1175/JCLI-D-12-00167.1 IdentifierSinclair2013Relevancerank5

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Bertler, N.