Evidence of anthropogenic climate effects in snow and firn of East Antarctica? Characterization of low accumulation areas using multiparameter-analysis from snow and firn cores

• Main Author: Weinhart, Alexander Helmut
• Format: Thesis
• Language: unknown
• Published: 2021
• Subjects: Antarc*; Antarctic; Antarctica; East Antarctica; Ice Sheet; West Antarctica
• Online Access: https://epic.awi.de/id/eprint/56782/; https://epic.awi.de/id/eprint/56782/2/Evidence_of_anthropogenic_climate_effects_in_snow_and_firn_of_East_Antarctica.pdf; https://hdl.handle.net/10013/epic.cd0572c0-b964-4143-b7fd-090401f508f8

Antarctica is a fundamental element of the global climate system. On the one hand, the ice masses of Antarctica are a unique climate archive that has steadily piled up over millennia. Analyses of stable water isotopes (δ18O and δ2H) and aerosols (including ions from sea salt and biogenic emissions), which serve as indirect indicators of climate in ice cores ("climate proxies"), make reconstructions of climate history possible. Gas inclusions in the ice even allow a direct study of the paleoatmosphere. On the other hand, Antarctica is strongly affected by global climate change. Rising temperatures cause a widespread mass loss in West Antarctica and a regional mass loss in East Antarctica. The whole Antarctic ice sheet may contribute to a global sea level rise of about 60 m if it melts entirely. This work provides important insights into both research aspects of glaciology – the look into the past and into the future. Particularly in areas that are logistically difficult to access, such as the East Antarctic Plateau, field data are scarce. However, these are essential both for studying the signal formation of climate proxies and for validating results from (satellite-based) remote sensing. The East Antarctic Plateau extends from 20°W to 45°E above an elevation of 2000 m asl. During the Antarctic summer of 2016/17, snow cores were sampled in that area on a traverse between Kohnen Station (0° 4’E, 75° 0’S) and the abandoned Plateau Station (40° 33’E, 79° 15’S). X-ray computed tomography was used to determine the density and stratigraphic properties of the snow. The cores were then cut into individual samples at 1 cm or 2 cm resolution under clean room conditions at -18°C, for which a special instrument was developed as part of this study. The distinct samples were analyzed for stable water isotopes as well as major ions. This approach of a multiparameter analysis allows a combined look at different individual parameters and thus better understand the snowpack history. Multiple snow cores per sampling location allow ...