For over 20 years, a fleet of almost four thousand floating scientific instruments called Argo floats have been measuring ocean temperature and salinity across the globe. The program was recently expanded to include floats that measure additional variables to shed light on biogeochemical ocean processes. A new study, supported by a partnership between CPO’s Climate Observations and Monitoring (COM) Program, Climate Variability and Predictability (CVP) Program, and NOAA’s Global Ocean Monitoring and Observing (GOMO) Program, takes a closer look at the new Argo capabilities and evaluates their effectiveness. NOAA-funded researchers Matthew Mazloff and Bruce Cornuelle of Scripps Institution of Oceanography at the University of California, San Diego were supported by two grants for this research. The joint COM-CVP-GOMO grant focuses on increasing the use and value of ocean observations, advancing our understanding of climate variability and change, and enhancing NOAA’s ability to model and predict the Earth System. CVP funding is aimed at building upon and refining the current scientific understanding of the equatorial Pacific climate system, as part of an ongoing series of process studies to improve the Tropical Pacific Observing System (TPOS).
For the first time, the new biogeochemical Argo floats will provide real-time continuous measurements of nitrate, oxygen, chlorophyll, and pH to help scientists understand biogeochemical cycles in the open ocean. The eventual global array of these floats are planned to be evenly spaced across the global oceans. This study investigated whether this uniform distribution is the most effective using current Argo observations and trajectories as well as modeled ocean conditions and found some exceptions. For example, the western tropical Pacific has low variability in the biogeochemical factors and may require sparser coverage. The results, published in an early online release in the Journal of Atmospheric and Oceanic Technology, provide a map of the optimal global distribution of Argo floats for future deployment. This work is a first step towards upgrading Argo float efficiency using an observations-based approach, which can be of great benefit to the TPOS effort.