Ocean ventilation and deoxygenation in a warming world: posters

Abstract

The Guest Editors wish to thank the poster presenters from the ‘Ocean ventilation and deoxygenation in a warming world’ discussion meeting. Their contributions are listed here. P. A. Pickers1, A. C. Manning1, W. T. Sturges1, C. Le Quere2, S. Mikaloff-Fletcher3, P. A. Wilson1 and A. J. Etchells1 1Centre for Ocean and Atmospheric Sciences, School of Environmental Sciences, University of East Anglia, Norwich, UK 2Tyndall Centre for Climate Change Research, School of Environmental Sciences, University of East Anglia, Norwich, UK 3National Institute of Water and Atmospheric Research, Wellington 6021, New Zealand Here, the group present the first meridional transects of atmospheric O2, CO2 and atmospheric potential oxygen (APO; a measure of the ocean-influenced component of atmospheric oxygen variations) over the Atlantic Ocean, from an in situ measurement system deployed on board a commercial container ship during 2015. These data provide new insights into short-term and seasonal variability in O2, CO2 and APO over the Atlantic Ocean. Modelling studies predict an Atlantic equatorial APO ‘bulge’, predominantly caused by thermally driven outgassing of O2 from the tropics; however, this APO bulge is not apparent in shipboard observations. It is possible that the ‘missing’ bulge was caused by the development of strong El Nino conditions during 2015; e.g. the El Nino event of 2009/2010 is thought to have suppressed the western Pacific APO bulge. Examination of the Inter Tropical Convergence Zone position, Atlantic Meridional Mode index and modelled O2, CO2 and N2 air–sea fluxes, however, suggest that neither atmospheric transport nor the equatorial Atlantic Ocean fluxes were particularly unusual during 2015 compared to previous years. Thus, the group speculate that the ‘missing’ equatorial APO bulge is likely a …