New carbonyl sulfide measurements in the Southern Ocean

Monday, 19 March 2018
Iriarte (Hotel Botanico)
Stefanie Kremser, Bodeker Scientific, Alexandra, New Zealand, Sinikka T. Lennartz, GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany, Marc von Hobe, Forschungszentrum Jülich GmbH, Inst. of Energy and Climate Research (IEK-7), Juelich, Germany and Mike Harvey, National Institute of Water and Atmospheric Research, Wellington, New Zealand; NIWA, Wellington, New Zealand
Abstract:
Stratospheric sulfate aerosol affects chemical and climate processes over Antarctica and the Southern Ocean. A significant source of stratospheric sulfate is the long-lived reduced sulfur gas carbonyl sulfide (OCS). According to biogeochemical models, the Southern Ocean represents an important natural OCS source. However, measurements in the Southern Ocean are sparse and therefore large uncertainties in OCS emissions remain.

Here we present new OCS measurements that will be made during a ship cruise into the Southern Ocean in early 2018. The research vessel RV Tangaroa, having a wide range of instrumentation on-board, will sail from New Zealand to the Ross Sea, measuring a range of atmospheric and oceanic parameters. The Tangaroa voyage will provide continuous measurements of OCS, CO, DMS, along with meteorological measurements such as sea surface temperature, UV, and wind speed, and underway parameters such as optical properties related to the amount and nature of the chromophoric dissolved organic matter (CDOM) present. OCS and CO will be measured by Integrated Cavity Output Spectroscopy (ICOS) using the prototype of a commercial instrument, developed by Los Gatos Research (LGR) in collaboration with Forschungszentrum Jülich. To also measure dissolved OCS concentrations in the surface layer of the ocean, a seawater equilibrator will be used through which seawater is pumped from approximately 5 m below the surface.

These newly obtained OCS measurements can be used to accurately determine sea-air fluxes, improve models and better understand how the Southern Ocean impacts OCS on global scale.

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