Origin of precipitation of the Northern Antarctic Peninsula and Shetlands Islands: Preliminary results

In order to asses the climate variability of a highly susceptible region to climate change, isotope studies were carried out in the Chilean Antarctic sector. During the year 2008, a daily precipitation collection has been started in two different stations: Fildes Peninsula (King George Island) and OŽHiggins Station (Antarctic Peninsula). The first geochemical analysis for samples collected during January and February of 2008 (n=12), shows mean isotope values of -8.16 δ18O and -64 δD vs. VSMOW (amount weighted). The calculated d-excess (d= δD-8*δ18O) values vary between -0.7 and 4.2 most likely reflecting different physical-chemical conditions during primary evaporation in the moisture source. For every registered event, 3-days backward air trajectories were computed. For this study the NOAA Hysplit v4.8 model was used, which was fed with GDAS (NCEP) meteorological archives. From d-excess values and trajectories, 4 main provenance directions were identified: South-West Pacific, Bellingshausen Sea, South Atlantic and a South Pacific/South America sector.During the past austral summer season (January/February 2008) a short firn core (15 m depth) was retrieved close to the OŽHiggins Station (300 m a.s.l.). High resolution (5 cm) isotope analysis was carried out for this core. These data indicate likely, that the age of the core is between 3 and 4 years. Isotope signals are partially smoothed by melting and percolation processes. For this reason, it is aimed to retrieve cores at higher altitudes on Plateau Laclavére in the following field season