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UP: Fachverband Umweltphysik
UP 9: Applied Noble Gas Physics Part 2
UP 9.3: Hauptvortrag
Donnerstag, 26. März 2015, 15:30–16:00, C/gHS
Applications of Noble Gases in Oceanography — •Peter Schlosser1,2,3, Robert Newton3, Gisela Winckler3, and Angelica Pasqualini2,3 — 1Dept of Earth and environmental Sciences, Columbia Universiy — 2Dept of Earth and Environmental Engineering, Columbia University — 3Lamont-Doherty Earth Observatory, Columbia University
Over the past decades, methods for detection and routine measurement of noble gases and their isotopes at ultra-low levels have been developed. They enabled application of these trace substances to many problems of ocean circulation, dynamics, and air/sea exchange. In principle, noble gases are used in studies such as (1) radioactive clocks (Tritium/He-3; Ar-39), (2) natural or anthropogenic injections into specific water masses (He isotopes), and (3) global dyes (Kr-85 or the quasi noble gas sulfurhexafluoride). To illustrate these applications three oceanographic noble gas studies are presented and discussed. Determination of the major circulation pathways and man residence times of the waters in the Arctic Ocean (tritium/He-3; Ar-39): knowledge of the Arctic Ocean circulation pattern is needed to understand the implications of rapid Arctic Environmental Change. Large-scale mixing at mid-depth in the Pacific Ocean: the turbulent mixing coefficients derived from these studies are used to quantify redistribution of water and dissolved substances (He-3). Air/sea exchange, especially in the high-wind regimes of the Southern Ocean: air/sea gas exchange rates, together with measurements of the partial pressure of carbon dioxide, are applied to calculate the uptake of carbon by the oceans.