Bremen 2017 – wissenschaftliches Programm
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UP: Fachverband Umweltphysik
UP 2: Ozeanographie/Hydrosphäre
UP 2.3: Vortrag
Dienstag, 14. März 2017, 09:30–09:45, GW2 B3009
Worldwide First Below-Shelf-Ice Noble Gas Measurements to Investigate Basal Melting Below the Filchner-Ice-Shelf in Antarctica — •Oliver Huhn1,2, Tore Hattermann2, Jürgen Sültenfuß1, Hartmut Hellmer2, Monika Rhein1,3, Michael Schröder2, Torsten Kanzow2, and Erich Dunker2 — 1Institut für Umweltphysik IUP, Abt. Ozeanographie, Universität Bremen, Germany — 2Alfred-Wegener-Institut AWI, Helmholz-Zentrum für Polar- und Meeresforschung, Bremerhaven, Germany — 3Zentrum für Marine Umweltwissenschaften MARUM, Universität Bremen, Germany
Low soluble, stable noble gases as helium and neon are ideal tracers to quantify basal glacial melt water in ocean water. Atmospheric air trapped in meteoric ice is fully dissolved when the ice is melted from below due to the enhanced hydrostatic pressure at the underside of an floating ice shelf, leading to an excess of 1280 % for He and 890% for Ne in pure glacial melt water. We have carried out the worldwide first noble gas measurements from below an ice shelf in Antarctica. We constructed and successfully tested a dedicated in-situ water sampler for oceanic noble gas measurements under extremely cold conditions to avoid freezing and gas fractionation. The sampler was released through hot-water drilled bore holes at two locations below the Filchner-Ice-Shelf in the Weddell Sea. We observed substantial melt water fractions below the Filchner Ice Shelf. These measurements will help us obtain a better understanding of basal melting processes at the source and to quantify basal ice shelf melting, which is crucial to investigate the fate of Antarctic and Arctic ice shelves under changing climate conditions.