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.
Helmholtz Research Programs > MARCOPOLI (2004-2008) > POL6-Earth climate variability since the Pliocene