Contemporary meteorological observations facilitate interpretation of a multi-century long ice core from the Antarctic Peninsula

The exceptionally high annual accumulation on the Bruce Plateau in the Antarctic Peninsula facilitates the preservation of annually resolved ice-core derived proxy records in this climatically sensitive region that has experienced a strong warming (~2.5 °C) over the last half century (Turner et al., 2005). A 448.12 meter ice core drilled to bedrock in 2010 at LARISSA Site Beta (66°02'S; 64°04'W; 1975 m a.s.l.) will provide multi-century long proxy histories of temperature and precipitation as well atmospheric turbidity and chemistry. Accurate interpretation of these proxy data requires assessing how well they record conditions in the region. Contemporary meteorological observations at nearby stations are used to make this assessment and to calibrate the proxy indicator (ä18O) for regional air temperature. Meteorological observations are available from two permanent bases situated on the western side of the Peninsula. The Faraday / Vernadsky Station, ~90 km north of the drill site, has observations extending back to 1950 CE while Rothera Station, ~250 km to the south, has observations extending back to 1977 CE. The high annual accumulation at the drill site makes seasonal resolution of the upper annual layers possible and facilitates comparison of the ice core proxy records with monthly to seasonal averages of temperature, precipitation, wind speed and wind direction. Further insight to the mechanisms producing the ice-core derived proxy records comes from examination of the contemporaneous characteristics of the larger-scale atmospheric circulation patterns. These are available from two reanalysis products from the European Centre for Medium range Weather Forecasting (ECMWF): ERA-40, 1957 to 2002 (Uppala et al., 2005) and ERA-Interim, 1979 onward (Dee et al., 2011).