Stable water isotopes of precipitation and firn cores from the northern Antarctic Peninsula region as a proxy for climate reconstruction

Abstract

Abstract. In order to investigate the climate variability in the northern Antarctic Peninsula region, this paper focuses on the relationship between stable isotope content of precipitation and firn, and main meteorological variables (air temperature, relative humidity, sea surface temperature, and sea ice extent). Between 2008 and 2010, we collected precipitation samples and retrieved firn cores from several key sites in this region. We conclude that the deuterium excess oscillation represents a robust indicator of the meteorological variability on a seasonal to sub-seasonal scale. Low absolute deuterium excess values and the synchronous variation of both deuterium excess and air temperature imply that the evaporation of moisture occurs in the adjacent Southern Ocean. The δ 18 O-air temperature relationship is complicated and significant only at a (multi)seasonal scale. Backward trajectory calculations show that air-parcels arriving at the region during precipitation events predominantly originate at the South Pacific Ocean and Bellingshausen Sea. These investigations will be used as a calibration for ongoing and future research in the area, suggesting that appropriate locations for future ice core research are located above 600 m a.s.l. We selected the Plateau Laclavere, Antarctic Peninsula as the most promising site for a deeper drilling campaign.

New insights into the climatic signal from firn cores at the northern Antarctic Peninsula

“…Thus, this reassures that postdepositional processes in the LCL region are negligible in the time period analyzed and that ice layers likely developed by 20 wind ablation on wind-scouring processes at the plateau. Although these observations are in agreement with the results obtained in this region by Fernandoy et al (2012) and Aristarain et al (1990), several studies (Fernandoy et al, 2012;Simões et al, 2004;Travassos and Simoes, 2004;Jiahong et al, 1998) have identified a significant amount of melt layers in firn cores, mainly from KGI and from the western side of the API at altitudes below 700 m a.s.l. The limited effect of post−depositional processes due to the high accumulation rates and to the ice layers reducing diffusion (Stichler et al, 2001), along with the high 25 correlation between dexcess meteo and dexcess obtained from firn cores, confirm that the isotopic variations observed in firn core isotope records are mostly related to isotopic fractionation occurring during condensation and to rh and SST conditions in the vapor source regions.…”

“…More than 200 daily precipitation samples were gathered from O´Higgins Station (57.90°W, 63.32°S, 13 m a.s.l.) during 2008-2009(Fernandoy et al, 2012 and 2014 ( Table 2). Some of these samples were discarded from the analysis due to improper storing.…”

“…Some of these samples were discarded from the analysis due to improper storing. Cores OH-4, OH-5, OH-6 and OH-9 were retrieved between 2008 and 2010 and analyzed for their stable water isotope composition and physical properties as described in Fernandoy et al (2012) and Meyer et al (2000). Additionally, a density profile of OH-9 was obtained 10 by using an X-ray microfocus computer tomograph at the ice core processing facilities of the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research in Bremerhaven, Germany (Linow et al, 2012).…”

“…1100 m a.s.l. (Fernandoy et al, 2012), where the ice thickness reaches ca. 350 m at its highest surface point (Cárdenas et al, 2014) .…”

“…The increase of greenhouse gas concentrations and the stratospheric depletion of the ozone layer, both linked to anthropogenic activity, are suggested to be the main forcing factors of the climate shift that affects the ocean-atmosphere-cryosphere system for at least the last half century (Fyfe and Saenko, 2005;Sigmond et al, 2011;Fyfe et al, 2007).…”