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Understanding 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 high-resolution 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 δD) in the ice core record. In cold months (low δD), 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. [ABSTRACT FROM AUTHOR]

A 125-yr ice core record of climate from the Whitehall Glacier ice divide provides exceptionally high-resolution stable isotope data from the northwest margin of the Ross Sea, Antarctica. This is the only proxy data available to extend the instrumental record of temperature in this region, where little is known about climate variability over the past two centuries. Using ECMWF Interim Re-Analysis (ERA-Interim) data, this study develops a precipitation-weighted δ18O-temperature transfer function of 0.62‰ °C−1, which is comparable to other proximal ice cores, such as Taylor, Talos, and Law Domes. Reconstructed mean annual temperatures show no significant change between 1882 and 2006. However, a decrease in cold season [April-September (AMJJAS)] temperatures of −1.59° ± 0.84°C decade−1 (at 90% confidence) is observed since 1979. This cooling trend is in contrast to a surface temperature record from Ross Island (Scott Base) where significant spring warming is observed. It is also coincident with a positive trend in the southern annular mode, which is linked to stronger southerly winds and increased sea ice extent and duration in the western Ross Sea. [ABSTRACT FROM AUTHOR]