The ocean's role in climate

Author Posting. © The Oceanography Society, 2018. This article is posted here by permission of The Oceanography Society for personal use, not for redistribution. The definitive version was published in Schmitt, R.W. The ocean’s role in climate. Oceanography 31(2): (2018): 32–40, doi:10.5670/oceanog.2018.225.Oceanographers have arrived late to the climate problem. Continuous climate records longer than a century or more are available for many cities, but are unheard of for the ocean. In the last 30 years, there has been great progress in expanding ocean observations to the point that we can start to address climate problems, but the shortness of the records is a constant impediment to progress. Of course, we are also now in an era when the climate problem looms larger than ever. Once the unhurried domain of state climatologists, the rapid buildup of atmospheric CO2 in the industrial era has turned climate into one of the most critical of all research topics. While we remain limited by short time series, the basics physics of the climate system assures a significant place for the ocean because it dominates the planetary reservoirs of heat, water, and CO2. This article summarizes the ocean’s essential contributions to the maintenance of Earth’s climate and asserts the need for sustaining a high quality ocean observing system for the long durations necessary to observe and understand climate.Julian Schanze and Sam Levang assisted with figures. Support was provided by National Science Foundation grant OCE-1433132

An old salt retires

Author Posting. © The Oceanography Society, 2015. This article is posted here by permission of The Oceanography Society for personal use, not for redistribution. The definitive version was published in Oceanography 28, no. 1 (2015): 7, doi:10.5670/oceanog.2015.20.In September and October 2012, R/V Knorr operated in the North Atlantic to deploy autonomous platforms that would collect measurements over the following year for the first phase of the Salinity Processes in the Upper-ocean Regional Study (SPURS-1). When the ship was retired in late 2014, after 44 years of oceanographic service, a plaque on the bridge still displayed the vessel’s motto, "Sal sume sub sole," which was provided by Emerson Hiller, the first captain

Double diffusion in oceanography : proceedings of a meeting September 26-29, 1989

A meeting to review research progress on double-diffusive phenomena in the ocean was held September 26-29, 1989, at the Woods Hole Oceanographic Institution. Twenty-five oral presentations were made and a number of discussion sessions were held. This report contains manuscripts provided by meeting participants, summaries of the discussion sessions and an extensive bibliography on oceanic double-diffusion. Since double-diffusive processes appear to play an important role in ocean mixing, further research in this field should have high priority. It is hoped that this update on the status of our current understanding will facilitate planning of additional research.Funding was provided by the National Science Foundation under grant No. OCE 88-13060

Finger puzzles

Author Posting. © Cambridge University Press, 2012. This article is posted here by permission of Cambridge University Press for personal use, not for redistribution. The definitive version was published in Journal of Fluid Mechanics 692 (2012): 1-4, doi:10.1017/jfm.2011.468.Salt fingers are a form of double-diffusive convection that can occur in a wide variety of fluid systems, ranging from stellar interiors and oceans to magma chambers. Their amplitude has long been difficult to quantify, and a variety of mechanisms have been proposed. Radko & Smith (J. Fluid Mech., this issue, vol. 692, 2012, pp. 5–27) have developed a new theory that balances the basic growth rate with that of secondary instabilities that act on the finite amplitude fingers. Their approach promises a way forward for computationally challenging systems with vastly different scales of decay for momentum, heat and dissolved substances.2013-01-2

Thermohaline convection at density ratios below one : a new regime for salt fingers

Author Posting. © Sears Foundation for Marine Research, 2011. This article is posted here by permission of Sears Foundation for Marine Research for personal use, not for redistribution. The definitive version was published in Journal of Marine Research 69 (2011): 779-795, doi:10.1357/002224011799849471.New experimental results on haline convection show a surprising preference for narrow fingers over large-scale convection when even a small stabilizing temperature gradient is present (Hage and Tilgner, 2010). This regime has heat/salt density ratios below one, a parameter range that has not been explored in traditional salt finger theory. Here the properties of the exact (long finger) solutions of Schmitt (1979, 1983) are explored at low density ratios. It is found that narrow finger solutions are indeed obtained and remain the fastest growing in some circumstances, though the selective advantage of the “Stern scale“ can disappear as the density ratio decreases. The variation of solutions with Prandtl number and the relation to the Stern (1975) approximate solution are examined and discussed.The financial support of NASA for this work under grant NNX10AE19G is also gratefully acknowledged

Salinity and the global water cycle

Author Posting. © Oceanography Society, 2008. This article is posted here by permission of Oceanography Society for personal use, not for redistribution. The definitive version was published in Oceanography 21, 1 (2008): 12-19.The support of the National Science Foundation under grant OCE-0647949 to RWS is also acknowledged, as is the Oceans and Climate Change Institute of the Woods Hole Oceanographic Institution

Flux measurements on salt fingers at an interface

A series of two-layer, heat-salt fingering experiments were performed in a one meter deep insulated tank. Repeated profiling of the temperature and conductivity with a small probe allowed the calculation of the vertical fluxes of heat and salt…

A river of salt

Author Posting. © The Oceanography Society, 2015. This article is posted here by permission of The Oceanography Society for personal use, not for redistribution. The definitive version was published in Oceanography 28, no. 1 (2015): 40-45, doi:10.5670/oceanog.2015.04.Terrestrial rivers are a well-known part of the global water cycle, and there has been recent discussion of “atmospheric rivers” that transport vast quantities of moisture from the tropical ocean to mid-latitudes in transient weather systems. Complementary “salt rivers” within the ocean are an equally important part of the global water cycle. They help define the ocean’s methods of returning water to where it is needed to maintain sea level and the global water cycle. One part of the Salinity Processes in the Upper-ocean Regional Study (SPURS) focused on the North Atlantic surface salinity maximum, where high evaporation rates remove freshwater from the ocean surface and leave dissolved salts behind. Much of the effort is devoted to understanding how that salty water disperses through lateral and vertical mixing processes. One important exit path is simple advection within the general circulation, which in the central Atlantic means the wind-driven “Sverdrup” circulation. Evaporation results in high salinity within the flow, marking a subsurface salt river within the ocean. Here, we examine the river’s structure as revealed in the average salinity field of the North Atlantic. Mid-ocean salinity maxima provide a unique opportunity to use an isohaline control volume approach for analyzing the mixing processes that disperse the high-salinity plume.RWS was supported by grants NNX12AF59G from NASA and 1129646 from the National Science Foundation. AB was supported by a Summer Student Fellowship from the Woods Hole Oceanographic Institution

Finestructure and microstructure in the North Atlantic Current

The relationship between intrusive finestructure and optical microstructure was studied by simultaneous CTD Tow-yos and deployments of the shadowgraph profiler SCIMP. Strong thermohaline intrusions, 5 to 50 m thick, were tracked laterally for 5 to 10 km in the front associated with the North Atlantic Current...