Riser Stephen C.
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ArticleThe technological, scientific, and sociological revolution of global subsurface ocean observing(Oceanography Society, 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.
ArticleSupercooled Southern Ocean waters(American Geophysical Union, 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.
ArticleThe Global Ocean Biogeochemistry (GO-BGC) array of profiling floats to observe changing ocean chemistry and biology(Marine Technology Society, 2022-06) Matsumoto, George I. ; Johnson, Kenneth S. ; Riser, Stephen C. ; Talley, Lynne D. ; Wijffels, Susan E. ; Hotinski, RobertaThe 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?
Working PaperBuilding a Community of Biogeochemistry Float Data Users: an OCB and US CLIVAR Report(Woods Hole Oceangraphic Institution, 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, HeidiThe 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.