scholarly journals The exchange of Intermediate Water in the southeast Atlantic: Water mass transformations diagnosed from the Lagrangian analysis of a regional ocean model

2012 ◽  
Vol 117 (C8) ◽  
pp. n/a-n/a ◽  
Author(s):  
Julie Rimaud ◽  
Sabrina Speich ◽  
Bruno Blanke ◽  
Nicolas Grima
Keyword(s):  
Water Mass ◽  
Atlantic Water ◽  
Ocean Model ◽  
Intermediate Water ◽  
Lagrangian Analysis ◽  
Regional Ocean Model ◽  
Water Mass Transformations

scholarly journals Eddy-Resolving Model Estimate of the Cabbeling Effect on the Water Mass Transformation in the Southern Ocean

2012 ◽  
Vol 42 (8) ◽  
pp. 1288-1302 ◽  
Author(s):  
L. Shogo Urakawa ◽  
Hiroyasu Hasumi
Keyword(s):  
Southern Ocean ◽  
Deep Water ◽  
Water Mass ◽  
Formation Rate ◽  
Ocean Model ◽  
Intermediate Water ◽  
Mode Water ◽  
Model Estimate ◽  
Circumpolar Deep Water ◽  
Water Mass Transformation

Abstract Cabbeling effect on the water mass transformation in the Southern Ocean is investigated with the use of an eddy-resolving Southern Ocean model. A significant amount of water is densified by cabbeling: water mass transformation rates are about 4 Sv (1 Sv ≡ 106 m3 s−1) for transformation from surface/thermocline water to Subantarctic Mode Water (SAMW), about 7 Sv for transformation from SAMW to Antarctic Intermediate Water (AAIW), and about 5 Sv for transformation from AAIW to Upper Circumpolar Deep Water. These diapycnal volume transports occur around the Antarctic Circumpolar Current (ACC), where mesoscale eddies are active. The water mass transformation by cabbeling in this study is also characterized by a large amount of densification of Lower Circumpolar Deep Water (LCDW) into Antarctic Bottom Water (AABW) (about 9 Sv). Large diapycnal velocity is found not only along the ACC but also along the coast of Antarctica at the boundary between LCDW and AABW. It is found that about 3 Sv of LCDW is densified into AABW by cabbeling on the continental slopes of Antarctica in this study. This densification is not small compared with observational and numerical estimates on the AABW formation rate, which ranges from 10 to 20 Sv.

scholarly journals AMOC, Water Mass Transformations, and Their Responses to Changing Resolution in the Finite‐VolumE Sea Ice‐Ocean Model

2020 ◽  
Vol 12 (12) ◽  
Author(s):  
Dmitry Sidorenko ◽  
Sergey Danilov ◽  
Vera Fofonova ◽  
William Cabos ◽  
Nikolay Koldunov ◽  
...  
Keyword(s):  
Sea Ice ◽  
Finite Volume ◽  
Water Mass ◽  
Ocean Model ◽  
Water Mass Transformations

Large-scale connections between Fram Strait recirculation and warm water pathways towards Greenland fjords

2021 ◽  
Author(s):  
Rebecca McPherson ◽  
Torsten Kanzow ◽  
Claudia Wekerle
Keyword(s):  
Large Scale ◽  
Atlantic Water ◽  
Ocean Model ◽  
Intermediate Water ◽  
Fram Strait ◽  
The Past ◽  
Subsurface Waters ◽  
West Spitsbergen ◽  
Annual Time

<p>In the last two decades, rising ocean temperatures have significantly contributed to the increased melting and retreat of marine-terminating glaciers along the coast of Greenland. Warming subsurface waters have also been shown to interact with the glaciers in Northeast Greenland, which until recently were considered stable, and caused their rapid retreat. The main source of these waters is the westward recirculation of subducted Atlantic Water (AW) in Fram Strait, which has shown a warming of up to 1° C over the past few decades.</p><p>In this study, the connection between the subsurface warm Atlantic Intermediate Water (AIW) found on the wide continental shelf of Northeast Greenland and in the fjords, and AW within the West Spitsbergen Current (WSC) is investigated using historical hydrographic observations and high-resolution numerical simulations with the Finite-Element Sea-ice Ocean Model (FESOM). We find that AW from the WSC takes between 10 – 14 months to recirculate across Fram Strait and reach the shelf break where it moves southwards. The pronounced inter-annual variability in the WSC is preserved as the water recirculates. However, the variability of temperature and AIW layer thickness on the shelf at seasonal or inter-annual time scales is at best weakly controlled by the AW temperature in the WSC. There is no significant correlation between AIW and the WSC anywhere on the shelf, suggesting advection from the WSC alone does not control AIW signals. The role of wind-driven, episodic upwelling is then investigated as a driver of transport of AIW from Fram Strait onto the shelf (following an approach by Münchow et al., 2020) where it then may follow the deep trough system towards the glaciers.</p>

scholarly journals Water Mass Transformation in Salinity–Temperature Space

2014 ◽  
Vol 44 (9) ◽  
pp. 2547-2568 ◽  
Author(s):  
Magnus Hieronymus ◽  
Johan Nilsson ◽  
Jonas Nycander
Keyword(s):  
Surface Area ◽  
Water Mass ◽  
Conveyor Belt ◽  
Ocean Model ◽  
Surface Fluxes ◽  
Area Distribution ◽  
Diabatic Processes ◽  
Major Transformation ◽  
Water Mass Transformation ◽  
Water Mass Transformations

Abstract This article presents a new framework for studying water mass transformations in salinity–temperature space that can, with equal ease, be applied to study water mass transformation in spaces defined by any two conservative tracers. It is shown how the flow across isothermal and isohaline surfaces in the ocean can be quantified from knowledge of the nonadvective fluxes of heat and salt. It is also shown how these cross-isothermal and cross-isohaline flows can be used to form a continuity equation in salinity–temperature space. These flows are then quantified in a state-of-the-art ocean model. Two major transformation cells are found: a tropical cell driven primarily by surface fluxes and dianeutral diffusion and a conveyor belt cell where isoneutral diffusion is also important. Both cells are similar to cells found in earlier work on the thermohaline streamfunction. A key benefit with this framework over a streamfunction approach is that transformation due to different diabatic processes can be studied individually. The distributions of volume and surface area in S–T space are found to be useful for determining how transformations due to these different processes affect the water masses in the model. The surface area distribution shows that the water mass transformations due to surface fluxes tend to be directed away from S–T regions that occupy large areas at the sea surface.

scholarly journals Variability of water mass properties in the Strait of Sicily in summer period of 1998–2013

Ocean Science ◽  
2014 ◽  
Vol 10 (5) ◽  
pp. 759-770 ◽  
Author(s):  
A. Bonanno ◽  
F. Placenti ◽  
G. Basilone ◽  
R. Mifsud ◽  
S. Genovese ◽  
...  
Keyword(s):  
Water Mass ◽  
Eastern Mediterranean ◽  
Water Layer ◽  
Atlantic Water ◽  
Northwestern Part ◽  
Intermediate Water ◽  
Strait Of Sicily ◽  
Surface Circulation ◽  
Deep Layers ◽  
First Time

Abstract. The Strait of Sicily plays a crucial role in determining the water-mass exchanges and related properties between the western and eastern Mediterranean. Hydrographic measurements carried out from 1998 to 2013 allowed the identification of the main water masses present in the Strait of Sicily: a surface layer composed of Atlantic water (AW) flowing eastward, intermediate and deep layers mainly composed of Levantine intermediate water (LIW), and transitional eastern Mediterranean deep water (tEMDW) flowing in the opposite direction. Furthermore, for the first time, the signature of intermittent presence of western intermediate water (WIW) is also highlighted in the northwestern part of the study area (12.235° E, 37.705° N). The excellent area coverage allowed to highlight the high horizontal and vertical inter-annual variability affecting the study area and also to recognize the permanent character of the main mesoscale phenomena present in the surface water layer. Moreover, strong temperature-salinity correlations in the intermediate layer, for specific time intervals, seem to be linked to the reversal of surface circulation in the central Ionian Sea. The analysis of CTD data in deeper water layer indicates the presence of a large volume of tEMDW in the Strait of Sicily during the summers of 2006 and 2009.

scholarly journals Variability of water mass properties in the Strait of Sicily in summer period of 1998–2013

2014 ◽  
Vol 11 (2) ◽  
pp. 811-837 ◽  
Author(s):  
A. Bonanno ◽  
F. Placenti ◽  
G. Basilone ◽  
R. Mifsud ◽  
S. Genovese ◽  
...  
Keyword(s):  
Thermohaline Circulation ◽  
Water Mass ◽  
Eastern Mediterranean ◽  
Subsurface Layer ◽  
Atlantic Water ◽  
Point Of View ◽  
Water Masses ◽  
Intermediate Water ◽  
Layer System ◽  
Strait Of Sicily

Abstract. The Strait of Sicily plays a crucial role in determining the water mass exchanges and related properties between western and eastern Mediterranean. The presence of sills to the east and west of the Strait of Sicily and the complex seabed topography modulate the thermohaline circulation of the Mediterranean basin. An anti-estuarine circulation is mainly characterized, from a dynamic point of view, by a two-layer system: a surface layer composed of Atlantic Water (AW) flowing eastward, essentially dominated by mesoscale processes, and a subsurface layer composed of Levantine Intermediate Water (LIW) flowing in the opposite direction; the topography appears to play an important role. Furthermore, there are transition water masses with variable hydrological characteristics. The dataset here studied is a time series 16 years long (1998–2013), which highlights the high horizontal and vertical interannual variability affecting the study area. Strong temperature-salinity correlations, in the intermediate layer, for specific time intervals, could be linked to the reversal of sub-surface circulation in the Central Ionian Sea. Moreover, a long-term monitoring of the hydrographic properties of water masses across this strait allow the modelers to assess the performance of hydrological models of this area.

scholarly journals Latest Miocene restriction of the Mediterranean Outflow Water: a perspective from the Gulf of Cádiz

2021 ◽  
Vol 41 (2) ◽  
Author(s):  
Zhi Lin Ng ◽  
F. Javier Hernández-Molina ◽  
Débora Duarte ◽  
Francisco J. Sierro ◽  
Santiago Ledesma ◽  
...  
Keyword(s):  
Mass Exchange ◽  
Water Mass ◽  
Atlantic Water ◽  
Meridional Overturning Circulation ◽  
Gulf Of Cadiz ◽  
Mediterranean Outflow Water ◽  
Gulf Of Cádiz ◽  
Mediterranean Outflow ◽  
The Mediterranean ◽  
Water Mass Exchange

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.

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