Comparison of Tritium/3He and SF6 Apparent Ages as Water Mass Dating Tools in the Switchyard Region of the Arctic Ocean

Dongping Song, Columbia University of New York, Department of Earth and Environmental Engineering, Palisades, NY, United States, Peter Schlosser, Arizona State University, Tempe, AZ, United States, Robert Newton, Lamont -Doherty Earth Observatory, Palisades, NY, United States; Columbia University of New York, Palisades, NY, United States and William M Smethie Jr, Lamont -Doherty Earth Observatory, Palisades, United States
Abstract:
We analyzed tritium (3H), helium isotope (3He and 4He) and sulfur hexafluoride (SF6) data collected in the ‘Switchyard’ region of the Arctic Ocean between 2008 and 2013. We calculated apparent ages using the 3H/3He ratios and the partial pressure of SF6 and compare their values for the depth interval between the surface and the core of the Atlantic Water layer. The apparent tracer ages range from zero to about 30 years. Generally, the correlation between the 3H/3He SF6 apparent ages correlate in a quasi-linear fashion. We explore deviations from this linear trend and discuss them in the context of mixing, air-sea gas exchange, and the impact of sea ice formation on the helium and SF6 gas balances in the surface mixed layer.
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