[O-07] The United Nations Decade of Ocean Science: Progress and Future Prospects

[O07-04] The Status of Argo and the UN Ocean Decade: Making OneArgo a Reality

★Invited Papers

*Toshio Suga^1,2 (1.Graduate School of Science, Tohoku University, 2.WPI-Advanced Institute for Marine Ecosystem Change, Tohoku University and JAMSTEC)

Keywords:Argo, Global Ocean Observing System, Global Warming, Carbon Cycle, Marine Ecosystem, Interdisciplinary Research

For more than 25 years, the International Argo Program, with the cooperation of more than 30 countries, has provided quasi-real-time temperature and salinity data for the upper 2000 meters of the world's oceans in a nearly homogeneous manner over time and space. Currently maintaining a network of approximately 4000 profiling floats and having acquired and released more than 3 million vertical profiles, Argo has revolutionized ocean observation and contributed to the advancement of ocean science as well as the monitoring of global warming and the accuracy of seasonal forecasts. The success of Argo and advances in float and sensor technology have raised expectations for the expansion of this observation system, and the international conference OceanObs'09 held in 2009 triggered full-scale discussions and deliberations regarding Argo expansion. OneArgo is a large-scale expansion of the Argo observation network, and it was proposed at OceanObs'19 in 2019, leading to a consensus among the ocean observing community. The Core mission is a network design that integrates Argo's original mission of measuring temperature and salinity profiles to a depth of 2000 m using floats that cover the open ocean at a density of approximately one float every three degrees of latitude and longitude at depths greater than 2000 m. The OneArgo design is a combination of the Core mission, the Deep mission, and the Biogeochemical (BGC) mission. The Deep mission is to measure temperature and salinity down to the seafloor, and the BGC mission is to measure dissolved oxygen, pH, nitrate, chlorophyll, optical backscatter, and irradiance down to 2000 m depth. The floats for these missions are called Deep floats and BGC floats, respectively. It is important to note that not only the Core floats, which are conventional floats, but also the Deep floats and BGC floats are responsible for the Core mission. OneArgo is a single observation system consisting of approximately 2500 Core floats, 1200 Deep floats, and 1000 BGC floats. OneArgo is expected to enable the full-depth monitoring of heat and freshwater redistribution and their contribution to sea level fluctuations, as well as the understanding of biogeochemical processes in the upper ocean and their contribution to the carbon cycle. It is also expected to promote the integration of different disciplines and provide various information and outcomes useful to society. On the other hand, the realization of OneArgo, which requires more than three times as much funding as the conventional Argo, requires the broad support of the scientific community and society. This is why the International Argo Steering Team is building OneArgo as a project of the UN Decade of Ocean Science for Sustainable Development. This talk will discuss the challenges to realizing OneArgo and the Argo community’s expectations for the UN Ocean Decade.