Riser Stephen C.

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Stephen C.
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The technological, scientific, and sociological revolution of global subsurface ocean observing

2022-01-07 , Roemmich, Dean , Talley, Lynne D. , Zilberman, Nathalie , Osborne, Emily , Johnson, Kenneth S. , Barbero, Leticia , Bittig, Henry C. , Briggs, Nathan , Fassbender, Andrea J. , Johnson, Gregory C. , King, Brian A. , McDonagh, Elaine L. , Purkey, Sarah G. , Riser, Stephen C. , Suga, Toshio , Takeshita, Yuichiro , Thierry, Virginie , Wijffels, Susan E.

The complementary partnership of the Global Ocean Ship-based Hydrographic Investigations Program (GO-SHIP; https://www.go-ship.org/) and the Argo Program (https://argo.ucsd.edu) has been instrumental in providing sustained subsurface observations of the global ocean for over two decades. Since the late twentieth century, new clues into the ocean’s role in Earth’s climate system have revealed a need for sustained global ocean observations (e.g., Gould et al., 2013; Schmitt, 2018) and stimulated revolutionary technology advances needed to address the societal mandate. Together, the international GO-SHIP and Argo Program responded to this need, providing insight into the mean state and variability of the physics, biology, and chemistry of the ocean that led to advancements in fundamental science and monitoring of the state of Earth's climate.

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Article

The Global Ocean Biogeochemistry (GO-BGC) array of profiling floats to observe changing ocean chemistry and biology

2022-06 , Matsumoto, George I. , Johnson, Kenneth S. , Riser, Stephen C. , Talley, Lynne D. , Wijffels, Susan E. , Hotinski, Roberta

The Global Ocean Biogeochemistry (GO-BGC) Array is a project funded by the US National Science Foundation to build a global network of chemical and biological sensors on Argo profiling floats. The network will monitor biogeochemical cycles and ocean health. The floats will collect from a depth of 2,000 meters to the surface, augmenting the existing Argo array that monitors ocean temperature and salinity. Data will be made freely available within a day of being collected via the Argo data system. These data will allow scientists to pursue fundamental questions concerning ocean ecosystems, monitor ocean health and productivity, and observe the elemental cycles of carbon, oxygen, and nitrogen through all seasons of the year. Such essential data are needed to improve computer models of ocean fisheries and climate, to monitor and forecast the effects of ocean warming and ocean acidification on sea life, and to address key questions identified in “Sea Change: 2015–2025 Decadal Survey of Ocean Sciences” such as: What is the ocean’s role in regulating the carbon cycle? What are the natural and anthropogenic drivers of open ocean deoxygenation? What are the consequences of ocean acidification? How do physical changes in mixing and circulation affect nutrient availability and ocean productivity?

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Article

On the future of Argo: A global, full-depth, multi-disciplinary array

2019-08-02 , Roemmich, Dean , Alford, Matthew H. , Claustre, Hervé , Johnson, Kenneth S. , King, Brian , Moum, James N. , Oke, Peter , Owens, W. Brechner , Pouliquen, Sylvie , Purkey, Sarah G. , Scanderbeg, Megan , Suga, Koushirou , Wijffels, Susan E. , Zilberman, Nathalie , Bakker, Dorothee , Baringer, Molly O. , Belbeoch, Mathieu , Bittig, Henry C. , Boss, Emmanuel S. , Calil, Paulo H. R. , Carse, Fiona , Carval, Thierry , Chai, Fei , Conchubhair, Diarmuid Ó. , d’Ortenzio, Fabrizio , Dall'Olmo, Giorgio , Desbruyeres, Damien , Fennel, Katja , Fer, Ilker , Ferrari, Raffaele , Forget, Gael , Freeland, Howard , Fujiki, Tetsuichi , Gehlen, Marion , Geenan, Blair , Hallberg, Robert , Hibiya, Toshiyuki , Hosoda, Shigeki , Jayne, Steven R. , Jochum, Markus , Johnson, Gregory C. , Kang, KiRyong , Kolodziejczyk, Nicolas , Körtzinger, Arne , Le Traon, Pierre-Yves , Lenn, Yueng-Djern , Maze, Guillaume , Mork, Kjell Arne , Morris, Tamaryn , Nagai, Takeyoshi , Nash, Jonathan D. , Naveira Garabato, Alberto C. , Olsen, Are , Pattabhi Rama Rao, Eluri , Prakash, Satya , Riser, Stephen C. , Schmechtig, Catherine , Schmid, Claudia , Shroyer, Emily L. , Sterl, Andreas , Sutton, Philip J. H. , Talley, Lynne D. , Tanhua, Toste , Thierry, Virginie , Thomalla, Sandy J. , Toole, John M. , Troisi, Ariel , Trull, Thomas W. , Turton, Jon , Velez-Belchi, Pedro , Walczowski, Waldemar , Wang, Haili , Wanninkhof, Rik , Waterhouse, Amy F. , Waterman, Stephanie N. , Watson, Andrew J. , Wilson, Cara , Wong, Annie P. S. , Xu, Jianping , Yasuda, Ichiro

The Argo Program has been implemented and sustained for almost two decades, as a global array of about 4000 profiling floats. Argo provides continuous observations of ocean temperature and salinity versus pressure, from the sea surface to 2000 dbar. The successful installation of the Argo array and its innovative data management system arose opportunistically from the combination of great scientific need and technological innovation. Through the data system, Argo provides fundamental physical observations with broad societally-valuable applications, built on the cost-efficient and robust technologies of autonomous profiling floats. Following recent advances in platform and sensor technologies, even greater opportunity exists now than 20 years ago to (i) improve Argo’s global coverage and value beyond the original design, (ii) extend Argo to span the full ocean depth, (iii) add biogeochemical sensors for improved understanding of oceanic cycles of carbon, nutrients, and ecosystems, and (iv) consider experimental sensors that might be included in the future, for example to document the spatial and temporal patterns of ocean mixing. For Core Argo and each of these enhancements, the past, present, and future progression along a path from experimental deployments to regional pilot arrays to global implementation is described. The objective is to create a fully global, top-to-bottom, dynamically complete, and multidisciplinary Argo Program that will integrate seamlessly with satellite and with other in situ elements of the Global Ocean Observing System (Legler et al., 2015). The integrated system will deliver operational reanalysis and forecasting capability, and assessment of the state and variability of the climate system with respect to physical, biogeochemical, and ecosystems parameters. It will enable basic research of unprecedented breadth and magnitude, and a wealth of ocean-education and outreach opportunities.

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Working Paper

Building a Community of Biogeochemistry Float Data Users: an OCB and US CLIVAR Report

2023-04-04 , Riser, Stephen C. , Fassbender, Andrea J. , Johnson, Kenneth S. , Sarmiento, Jorge L. , Talley, Lynne D. , Wijffels, Susan E. , Hotinski, Roberta , Gray, Alison R. , Takeshita, Yuichiro , Nicholson, David P. , Purkey, Sarah G. , Martz, Todd R. , Matsumoto, George I. , Cullen, Heidi

The Global Ocean Biogeochemistry (GO-BGC) array is a 5-year effort funded by the US National Science Foundation to produce and deploy 500 profiling floats equipped with biogeochemical sensors in the world ocean. Deployments began in the first quarter of 2021. To inform and engage a broad oceanographic user community, the Ocean Carbon & Biogeochemistry (OCB) and the US Climate Variability and Predictability (CLIVAR) Programs worked with GO-BGC leadership to host a virtual GO-BGC Scientific Workshop from June 28-30, 2021. The objectives of the workshop were to: • Introduce the GO-BGC plan to the global scientific community • Discuss and innovate on scientific applications of GO-BGC data • Provide background information on the flow of data and archiving • Deliver hands-on tutorials and computer code for accessing GO-BGC data Presentations and discussions were scheduled for 3-4 hours on each day using the Zoom platform. Some pre-recorded presentations were available online prior to each day’s events, so that participants could consider discussion items before the meeting. A Slack channel was also created prior to the meeting so that participants could communicate with organizers, presenters, and other attendees during the event.

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Article

Supercooled Southern Ocean waters

2020-10-09 , Haumann, F. Alexander , Moorman, Ruth , Riser, Stephen C. , Smedsrud, Lars H. , Maksym, Ted , Wong, Annie P. S. , Wilson, Earle A. , Drucker, Robert S. , Talley, Lynne D. , Johnson, Kenneth S. , Key, Robert M. , Sarmiento, Jorge L.

In cold polar waters, temperatures sometimes drop below the freezing point, a process referred to as supercooling. However, observational challenges in polar regions limit our understanding of the spatial and temporal extent of this phenomenon. We here provide observational evidence that supercooled waters are much more widespread in the seasonally ice‐covered Southern Ocean than previously reported. In 5.8% of all analyzed hydrographic profiles south of 55°S, we find temperatures below the surface freezing point (“potential” supercooling), and half of these have temperatures below the local freezing point (“in situ” supercooling). Their occurrence doubles when neglecting measurement uncertainties. We attribute deep coastal‐ocean supercooling to melting of Antarctic ice shelves and surface‐induced supercooling in the seasonal sea‐ice region to wintertime sea‐ice formation. The latter supercooling type can extend down to the permanent pycnocline due to convective sinking plumes—an important mechanism for vertical tracer transport and water‐mass structure in the polar ocean.

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Article

The Argo Program : present and future

2017-06 , Jayne, Steven R. , Roemmich, Dean , Zilberman, Nathalie , Riser, Stephen C. , Johnson, Kenneth S. , Johnson, Gregory C. , Piotrowicz, Stephen R.

The Argo Program has revolutionized large-scale physical oceanography through its contributions to basic research, national and international climate assessment, education, and ocean state estimation and forecasting. This article discusses the present status of Argo and enhancements that are underway. Extensions of the array into seasonally ice-covered regions and marginal seas as well as increased numbers of floats along the equator and around western boundary current extensions have been proposed. In addition, conventional Argo floats, with their 2,000 m sampling limit, currently observe only the upper half of the open ocean volume. Recent advances in profiling float technology and in the accuracy and stability of float-mounted conductivity-temperature-depth sensors make it practical to obtain measurements to 6,000 m. The Deep Argo array will help observe and constrain the global budgets of heat content, freshwater, and steric sea level, as well as the full-depth ocean circulation. Finally, another extension to the Argo Program is the addition of a diverse set of chemical sensors to profiling floats in order to build a Biogeochemical-Argo array to understand the carbon cycle, the biological pump, and ocean acidification.

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