On water mass exchange between the Southern Ocean and the World Ocean; emphasis on the Atlantic sector

1991 ◽  
Vol 35 (1-4) ◽  
pp. 1-7 ◽  
Author(s):  
Worth D. Nowlin
2021 ◽  
Vol 41 (2) ◽  
Author(s):  
Zhi Lin Ng ◽  
F. Javier Hernández-Molina ◽  
Débora Duarte ◽  
Francisco J. Sierro ◽  
Santiago Ledesma ◽  
...  

AbstractThe Mediterranean-Atlantic water mass exchange provides the ideal setting for deciphering the role of gateway evolution in ocean circulation. However, the dynamics of Mediterranean Outflow Water (MOW) during the closure of the Late Miocene Mediterranean-Atlantic gateways are poorly understood. Here, we define the sedimentary evolution of Neogene basins from the Gulf of Cádiz to the West Iberian margin to investigate MOW circulation during the latest Miocene. Seismic interpretation highlights a middle to upper Messinian seismic unit of transparent facies, whose base predates the onset of the Messinian salinity crisis (MSC). Its facies and distribution imply a predominantly hemipelagic environment along the Atlantic margins, suggesting an absence or intermittence of MOW preceding evaporite precipitation in the Mediterranean, simultaneous to progressive gateway restriction. The removal of MOW from the Mediterranean-Atlantic water mass exchange reorganized the Atlantic water masses and is correlated to a severe weakening of the Atlantic Meridional Overturning Circulation (AMOC) and a period of further cooling in the North Atlantic during the latest Miocene.


2016 ◽  
Vol 46 (12) ◽  
pp. 3751-3775 ◽  
Author(s):  
Olivier Arzel ◽  
Alain Colin de Verdière

AbstractThe turbulent diapycnal mixing in the ocean is currently obtained from microstructure and finestructure measurements, dye experiments, and inverse models. This study presents a new method that infers the diapycnal mixing from low-resolution numerical calculations of the World Ocean whose temperatures and salinities are restored to the climatology. At the difference of robust general circulation ocean models, diapycnal diffusion is not prescribed but inferred. At steady state the buoyancy equation shows an equilibrium between the large-scale diapycnal advection and the restoring terms that take the place of the divergence of eddy buoyancy fluxes. The geography of the diapycnal flow reveals a strong regional variability of water mass transformations. Positive values of the diapycnal flow indicate an erosion of a deep-water mass and negative values indicate a creation. When the diapycnal flow is upward, a diffusion law can be fitted in the vertical and the diapycnal eddy diffusivity is obtained throughout the water column. The basin averages of diapycnal diffusivities are small in the first 1500 m [O(10−5) m2 s−1] and increase downward with bottom values of about 2.5 × 10−4 m2 s−1 in all ocean basins, with the exception of the Southern Ocean (50°–30°S), where they reach 12 × 10−4 m2 s−1. This study confirms the small diffusivity in the thermocline and the robustness of the higher canonical Munk’s value in the abyssal ocean. It indicates that the upward dianeutral transport in the Atlantic mostly takes place in the abyss and the upper ocean, supporting the quasi-adiabatic character of the middepth overturning.


2002 ◽  
Vol 49 (16) ◽  
pp. 3127-3154 ◽  
Author(s):  
Olivier Ragueneau ◽  
Nicolas Dittert ◽  
Philippe Pondaven ◽  
Paul Tréguer ◽  
Lydie Corrin
Keyword(s):  

2007 ◽  
Vol 63 (2) ◽  
pp. 281-291 ◽  
Author(s):  
Kazuya Ono ◽  
Kay I. Ohshima ◽  
Tokihiro Kono ◽  
Motoyo Itoh ◽  
Katsuro Katsumata ◽  
...  

2021 ◽  
Author(s):  
Jose Perez-Asensio ◽  
Kazuyo Tachikawa ◽  
Laurence Vidal ◽  
Thibault de Garidel-Thoron ◽  
Corinne Sonzogni ◽  
...  

2021 ◽  
Vol 925 (1) ◽  
pp. 012013
Author(s):  
I P Anwar ◽  
M R Putri ◽  
A Tarya ◽  
I Mandang

Abstract Balikpapan Bay is enclosed water influenced by freshwater from river runoff and saline water from Makassar Strait. The exchange of water mass was examined by 3D numerical model simulation-Hamburg Shelf Ocean Model (HAMSOM) with horizontal resolutions approx. 150 m and 10 vertical layers applied in Balikpapan Bay. The thirteen tidal components, daily river runoff, atmospheric forcing, subsurface temperature, and Salinity in 3D used for model input. The tidal elevation from Geospatial Information Agency (BIG) model fits with this result from 01/03/2020 to 31/03/2020. It has coefficient correlation 0,99 with a significant level of 95% and Root Mean Square Error (RMSE) is 0,1 m. The volume and salt transport in the mouth (Line-A) and middle (Line-B) of bay was examined. The maximum transport in Line-A during spring (neap) high to low tide and low to high tide is −18364.72 m3/s (−1717.57 m3/s) and −17532.27 m3/s (4258.86 m3/s) for volume. Then, 531,947,898.90 kg.psu./s (−45,127,135.38 kg.psu./s) and −536,410,944.50 kg.psu./s (140,700,437.97 kg.psu./s) for salinity. Positive (negative) of water transport is inflow (outflow) to Balikpapan Bay. The net transport in a day during the spring (neap) is −832.45 m3/s (5976.43 m3/s) for volume and −4,463,045.58 kg.psu./s (185,827,573.35 kg.pau./s) for salt. The vertical structure of net volume and salt transport bot in Line-A and Line-B shows the water goes to outer bay in surface and inner bay in subsurface. While in the spring tide the surface deeper than neap tide. It indicated that water mass exchange dominantly influenced by river in surface and tidal in subsurface. It also shows that water mass from inner bay more easy flushing during spring tide than neap tide and vice versa


Author(s):  
Scott D. Bachman

AbstractThe identification of vortices in a fluid flow is a dynamically interesting problem that has practical applications in oceanography due to the outsized role eddies play in water mass, heat, and tracer transport. Here a new Eulerian scheme is developed to detect both vortices and strongly strained fronts, which are both ubiquitous in the world ocean. The new scheme is conceptually linked to the well-known Okubo-Weiss parameter, but is extended to quasigeostrophic flows by recognizing the strong role played by vertical shear in ocean dynamics. Adapted from the λ2-criterion for vortex identification (Jeong and Hussain 1995), the scheme considers the curvature of the pressure field as the differentiator between vortical and strained flow structures, and it is shown that its underlying geometry also exhibits characteristics of quasigeostrophic flow. The uses and skill of the scheme are demonstrated using a high-resolution regional ocean simulation, and prospects for its use with observational products are discussed.


2002 ◽  
Vol 188 (1-2) ◽  
pp. 165-192 ◽  
Author(s):  
T.L Rasmussen ◽  
D Bäckström ◽  
J Heinemeier ◽  
D Klitgaard-Kristensen ◽  
P.C Knutz ◽  
...  

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