Toward deeper development of Biogeochemical-Argo floats

Following a series of publications reporting on successful long-term deployments of profiling floats with various biogeochemical sensors (e.g. Boss et al. 2008; Johnson, Riser, and Karl 2010; Körtzinger et al. 2004) and years of international coordination, the BGC-Argo program was officially launched in October 2016, as an extension of the Argo Program (Biogeochemical-Argo Planning Group 2016; Johnson and Claustre 2016). The objectives of the BGC-Argo Program are to establish and sustain an array with 1000 floats within five years. Similar to Argo, this is a coordinated, voluntary, distributed, and multinational network of profiling floats, but with a significant addition of sensors. At the moment, the global network is progressively maturing through a cluster of national projects, e.g. the French SOCLIM project (http://soclim.com), United States’ SOCCOM project (http://soccom.princeton.edu), South Africa’s SOCCO BIO-ARGO project (http://socco.org.za/research/#Bio-optics), and Chinese ReMOCA project in the Southern Ocean; the European REMOCEAN project (http://remocean.eu) and Japanese INBOX project (http://www.jamstec.go.jp/ARGO/inbox) in the subtropical gyres; the United States’ NAAMES project (http://naames.larc.nasa.gov) and UK-BIO-ARGO project in the subpolar gyres; as well as the French NAOS project (http://en.naos-equipex.fr/) in the Mediterranean Sea and Polar Area. As of November 2017, there are 282 such operational floats working in the global ocean, mainly covering the Southern Ocean, Indian Ocean, eastern Pacific, Atlantic, and Mediterranean Sea (Figure 1). Six BGC-Argo core variables have been identified: dissolved oxygen, nitrate (NO3), pH, Chl-a, suspended particles, and downwelling irradiance (Figure 1).