Greifswald 2024 – wissenschaftliches Programm
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UP: Fachverband Umweltphysik
UP 5: Cryosphere and Arctic Oceans
UP 5.2: Vortrag
Mittwoch, 28. Februar 2024, 11:30–11:45, ELP 6: HS 4
Analyzing 39Ar depth profiles in the Arctic Ocean with the new ArTTA measuring technique — •Carl Kindermann1, Yannis Arck1, David Wachs1, Julian Robertz2, Markus Oberthaler2, and Werner Aeschbach1 — 1Institute of Environmental Physics, Heidelberg University, Heidelberg, Germany — 2Kirchhoff-Institute for Physics, Heidelberg University, Heidelberg, Germany
Timescales of ventilation of the Arctic Ocean are still only poorly known. The commonly used tracers for ocean ventilation studies like CFCs and SF6 are limited to young water masses that occur either close to the surface or in highly ventilated deep waters. The radioisotope 39Ar with its half-life of 268 years covers time scales of 50 to 1000 years, perfectly suited for the investigation of ventilation timescales of deep and intermediate water masses. The new measurement technique called Argon Trap Trace Analysis (ArTTA) is based on quantum-optical methods to catch and count single 39Ar atoms. In contrast to the previously used low-level counting method, which required about 1000 liters of water, ArTTA only requires sample sizes of a few liters of ocean water. The benefit of ArTTA for ocean studies is evident by enabling a better resolution of the water column at great depths. This contribution presents results of 39Ar depth profiles analyzed in the project Ventilation and Anthropogenic Carbon in the Arctic Ocean (VACAO), which is part of the Synoptic Arctic Survey carried out in summer 2021 (SAS21). Samples, taken in the Nansen, Amundsen and Makarov Basins, were measured with ArTTA.
Keywords: ArTTA; Argon 39; Artic Ocean; VACAO; Radio Isotope Dating