Oxygen White Paper

It describes a plan to deploy regional pilot arrays of Argo-equivalent floats (funded independently of Argo), equipped with oxygen sensors in order to evaluate the capabilities, costs and requirements of oxygen measurements as part of Argo. The Argo Steering Team welcomed the idea and has endorsed the continued planning phase of this pilot program. A white paper to promote the addition of oxygen sensors to the international Argo float program Prepared by Summary This white paper justifies and outlines a new international joint Argo-Oxygen program in order to determine, on a global-scale, seasonal to decadal timescale variations in sub-surface dissolved oxygen concentrations. We propose to achieve this goal by adding dissolved oxygen sensors to the floats of the successful Argo array, thus extending its measurement capabilities. This Argo-Oxygen program is motivated by the fact that oceanic dissolved oxygen concentration is a key quantity for ocean ecology and biogeochemistry. It permits study and quantification of a diverse and crucial set of processes. These processes include the detection of the oceanic impact of global warming on ocean biogeochemistry and circulation, the addition of unprecedented constraints on the export of biologically formed organic matter, and improved estimates of the oceanic uptake of anthropogenic CO 2. The addition of oxygen to the currently measured suite of temperature and salinity on Argo will represent a revolutionary step in our ability to observe the ocean's evolution over time, integrating biogeochemical and physical observations. This prospect is made possible by the success of the Argo program and the recent development of dissolved oxygen sensors that are both precise and stable over extended periods and can be easily integrated with the currently used Argo floats. Achieving the main goal of the Argo-Oxygen program does not require any appreciable changes in the deployment and operating strategies of the current Argo program and can therefore be implemented without significant negative impacts on the Argo core mission. Experience with the more than 70 Argo floats that have already been deployed with dissolved oxygen sensors suggests that the technology is ready for a first large-scale experiment, but that further evaluation and testing is needed before a global implementation is possible. We therefore propose that the Argo-Oxygen program be implemented in two phases. In the pilot phase, one or two test regions will be seeded extensively with floats, many of which will contain two oxygen sensors. The region's oxygen distribution will then be …