The very first transformation of the Mediterranean outflow in the Strait of Gibraltar

Abstract. All most recent papers about the Mediterranean Outflow (MO) assume that it is homogeneous at least in the western side of the Strait of Gibraltar and that its splitting into veins in the Atlantic Ocean is due to bathymetric effects at the Strait exit while we demonstrate that proofs about the MO heterogeneity within the whole Strait have been available since the mid 1980's at least. We focus herein on data collected at the Strait entrance in 1985 (Part 1), before analyzing 1985–1986 data within the Strait (Part 2) and data collected during the MO-2009 experiment at the Strait exit (Part 3). Having demonstrated that the MO is markedly heterogeneous from the Strait entrance to the Strait exit, our three papers demonstrate that the splitting into veins is essentially a direct consequence of the sea functioning. Indeed, veins have hydrological characteristics mainly dependent on those of the intermediate and deep Mediterranean Waters (MWs) formed in both the eastern and the western basins of the Sea, as well as on those of the Atlantic Waters (AWs) that mixed in the Strait with these MWs, the bathymetry at and downstream from the Strait exit playing a negligible role. Herein, we demonstrate that four-five MWs can be clearly identified at the Strait entrance, as we previously hypothesized, moreover forming relatively thick and homogeneous superimposed layers that are much more individualized than anywhere else in the Sea. For the first time ever, we provide numerous examples of density instabilities in all these layers that clearly illustrate the processes leading to such an increased stratification at the Strait entrance. So as to motivate theoretical analyses and numerical simulations that appear to be of dramatic interest, we hypothesize that the isopycnals slope (of a few %) across the Strait within the MO itself, that is a direct consequence of both the Coriolis effect and the different outflowing or overflowing velocities of the MWs, could be the main mechanism responsible for such a layering of the MO.

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About the seasonal and fortnightly variabilities of the Mediterranean outflow

Ocean Science Discussions ◽

10.5194/osd-7-2043-2010 ◽

2010 ◽

Vol 7 (6) ◽

pp. 2043-2058

Author(s):

C. Millot ◽

J. Garcia-Lafuente

Keyword(s):

Time Series ◽

Spatial Heterogeneity ◽

Seasonal Variability ◽

Internal Tide ◽

Atlantic Water ◽

Strait Of Gibraltar ◽

Mediterranean Outflow ◽

The Mediterranean

Abstract. CTD time series from the HYDRO-CHANGES programme and INGRES projects have been collected simultaneously (2004–2008) on the Moroccan shelf and at the Camarinal and Espartel Sills in the strait of Gibraltar. They provide information that supports results recently obtained from the analysis of the two former time series, as well as from a reanalysis of CTD GIBEX profiles (1985–1986). The outflow of Mediterranean Waters, which does not show a clear seasonal variability before entering the strait, strongly mixes within the strait, due mainly to the internal tide, with the seasonally variable inflow of Atlantic Water. The outflow thus gets marked seasonal and fortnightly variabilities within the strait. Furthermore, since the outflow entering the strait displays marked spatial heterogeneity and long-term temporal variabilities, predicting its characteristics when in the ocean appears almost impossible.

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Contourite processes associated with the Mediterranean Outflow Water after its exit from the Strait of Gibraltar: Global and conceptual implications

Geology ◽

10.1130/g35083.1 ◽

2014 ◽

Vol 42 (3) ◽

pp. 227-230 ◽

Cited By ~ 77

Author(s):

F.J. Hernández-Molina ◽

E. Llave ◽

B. Preu ◽

G. Ercilla ◽

A. Fontan ◽

...

Keyword(s):

Strait Of Gibraltar ◽

Mediterranean Outflow Water ◽

Mediterranean Outflow ◽

The Mediterranean

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Generation of Bedforms by the Mediterranean Outflow Current at the Exit of the Strait of Gibraltar

Atlas of Bedforms in the Western Mediterranean ◽

10.1007/978-3-319-33940-5_42 ◽

2016 ◽

pp. 273-280 ◽

Cited By ~ 1

Author(s):

G. Ercilla ◽

D. Casas ◽

F. J. Hernández-Molina ◽

C. Roque

Keyword(s):

Strait Of Gibraltar ◽

Mediterranean Outflow ◽

The Mediterranean

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About the seasonal and fortnightly variabilities of the Mediterranean outflow

Ocean Science ◽

10.5194/os-7-421-2011 ◽

2011 ◽

Vol 7 (3) ◽

pp. 421-428 ◽

Cited By ~ 6

Author(s):

C. Millot ◽

J. Garcia-Lafuente

Keyword(s):

Time Series ◽

North Atlantic ◽

North Atlantic Ocean ◽

Internal Tide ◽

Atlantic Water ◽

Strait Of Gibraltar ◽

The North ◽

Mediterranean Outflow ◽

The Mediterranean

Abstract. CTD time series from the HYDRO-CHANGES programme and INGRES projects have been collected simultaneously (2004–2008) on the shelf of Morocco and at the sills of Camarinal and Espartel in the strait of Gibraltar. They provide information that supports results recently obtained from the analysis of the two former time series, as well as from a reanalysis of GIBEX CTD profiles (1985–1986). The outflow of Mediterranean Waters, which does not show a clear seasonal variability before entering the strait, strongly mixes within the strait, due mainly to the internal tide, with the seasonally variable inflow of Atlantic Water. The outflow thus gets marked seasonal and fortnightly variabilities within the strait. Furthermore, since the outflowing waters entering the strait display marked spatial heterogeneity and long-term temporal variabilities, accurately predicting the characteristics of the Mediterranean outflow into the North Atlantic Ocean appears almost impossible.

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

Geo-Marine Letters ◽

10.1007/s00367-021-00693-9 ◽

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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