scholarly journals On the Mediterranean Water Composition

2016 ◽  
Vol 46 (4) ◽  
pp. 1339-1358 ◽  
Author(s):  
L. I. Carracedo ◽  
P. C. Pardo ◽  
S. Flecha ◽  
F. F. Pérez
Keyword(s):  
North Atlantic ◽  
Sea Water ◽  
Source Region ◽  
Intermediate Water ◽  
Strait Of Gibraltar ◽  
Atlantic Basin ◽  
North Atlantic Basin ◽  
Water Composition ◽  
The Mediterranean ◽  
Mediterranean Water

AbstractThe Mediterranean Outflow Water (MOW) spills from the Mediterranean Sea (east North Atlantic basin) west off the Strait of Gibraltar. As MOW outflows, it entrains eastern North Atlantic Central Waters (ENACW) and Intermediate Waters to form the neutrally buoyant Mediterranean Water (MW) that can be traced over the entire North Atlantic basin. Its high salinity content influences the thermohaline properties of the intermediate–deep water column in the North Atlantic and its dynamics. Here, the composition of MW in its source region (the Gulf of Cádiz, west off Strait of Gibraltar) is investigated on the basis of an optimum multiparameter analysis. The results obtained indicate that mixing of MOW (34.1% ± 0.3%) occurs mainly with overlying ENACW (57.1% ± 0.8%) in a process broadly known as central water entrainment. A diluted form (80% of dilution) of the Antarctic Intermediate Water (AAIW) reaches the region and also takes part in MW formation (8.3% ± 0.5%). Finally, the underlying Labrador Sea Water (LSW) also contributes (0.4% ± 0.1%) to the characteristics of MW. From these results and considering 0.74 Sverdrups (Sv; 1 Sv ≡ 106 m3 s−1) as the mean outflow of MOW, the MW exportation rate was inferred (2.2 Sv), which, decomposing MW, means that the MOW outflow is accompanied by 1.24 Sv of entrained ENACW, 0.18 Sv of AAIW, and <0.01 Sv of LSW.

scholarly journals A Model Analysis of the Behavior of the Mediterranean Water in the North Atlantic

2007 ◽  
Vol 37 (3) ◽  
pp. 764-786 ◽  
Author(s):  
Yanli Jia ◽  
Andrew C. Coward ◽  
Beverly A. de Cuevas ◽  
David J. Webb ◽  
Sybren S. Drijfhout
Keyword(s):  
North Atlantic ◽  
Current System ◽  
Global Ocean ◽  
Western Boundary ◽  
Depth Range ◽  
Strait Of Gibraltar ◽  
The North ◽  
The North Atlantic ◽  
The Mediterranean ◽  
Mediterranean Water

Abstract The behavior of the Mediterranean Water in the North Atlantic Ocean sector of a global ocean general circulation model is explored, starting from its entry point at the Strait of Gibraltar. The analysis focuses primarily on one experiment in which explicit watermass exchange between the Mediterranean Sea and the Atlantic at the Strait of Gibraltar is permitted. The model produces an exchange rate of approximately 1 Sv (Sv ≡ 106 m3 s−1). This is comparable to estimates derived from field measurements. The density of the Mediterranean outflow, however, is lower than observed, mainly because of its high temperature (more than 2°C higher than in reality). The lower density of the outflow and the model’s inadequate representation of the entrainment mixing in the outflow region cause the Mediterranean Water to settle in a depth range ∼800–1000 m in the North Atlantic, about 200 m shallower than observed. Here an interesting current system forms in response to the intrusion of the Mediterranean Water, involving three main pathways. In the first, the Mediterranean Water heads roughly westward across the basin and joins the deep western boundary current. In the second, the water travels northward along the eastern boundary reaching as far as Iceland, where it turns westward to participate in the deep circulation of the subpolar gyre. In the third, the water initially moves westward to the central Atlantic just north of 30°N before turning northwestward to reach an upwelling region at the Grand Banks off Newfoundland. At this location, the saline Mediterranean Water is drawn upward to the ocean upper layer and entrained into the North Atlantic Current system flowing to the northeastern basin; part of the current system enters the Nordic seas.

Seasonal Analysis of Air-Sea CO2 Flux Variability in the North Atlantic and the Southern Ocean 

2021 ◽  
Author(s):  
Paridhi Rustogi ◽  
Peter Landschuetzer ◽  
Sebastian Brune ◽  
Johanna Baehr
Keyword(s):  
Southern Ocean ◽  
Observational Data ◽  
North Atlantic ◽  
Seasonal Variability ◽  
Max Planck ◽  
Regional Patterns ◽  
Atlantic Basin ◽  
North Atlantic Basin ◽  
The North ◽  
The North Atlantic

&lt;p&gt;Understanding the variability and drivers of air-sea CO&lt;span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;/span&gt; fluxes on seasonal timescales is critical for resolving the ocean carbon sink's evolution and variability. Here, we investigate whether discrepancies in the representation of air-sea CO&lt;span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;/span&gt; fluxes on a seasonal timescale accumulate to influence the representation of CO&lt;span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;/span&gt; fluxes on an interannual timescale in two important ocean CO&lt;span&gt;&lt;sub&gt;2 &lt;/sub&gt;&lt;/span&gt;sink regions &amp;#8211; the North Atlantic basin and the Southern Ocean. Using an observation-based product (SOM-FFN) as a reference, we investigate the representation of air-sea CO&lt;span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;/span&gt; fluxes in the Max Planck Institute's Earth System Model Grand Ensemble (MPI-ESM GE). Additionally, we include a simulation based on the same model configuration, where observational data from the atmosphere and ocean components is assimilated (EnKF assimilation) to verify if the inclusion of observational data alters the model state significantly and if the updated modelled CO&lt;span&gt;&lt;sub&gt;2 &lt;/sub&gt;&lt;/span&gt;flux values better represent observations.&lt;/p&gt;&lt;p&gt;We find agreement between all three observation-based and model products on an interannual timescale for the North Atlantic basin. However, the agreement on a seasonal timescale is inconsistent with discrepancies as large as 0.26 PgC/yr in boreal autumn in the North Atlantic. In the Southern Ocean, we find little agreement between the three products on an interannual basis with significant seasonal discrepancies as large as 1.71 PgC/yr in austral winter. However, while we identify regional patterns of dominating seasonal variability in MPI-GE and EnKF, we find that the SOM-FFN cannot demonstrate robust conclusions on the relevance of seasonal variability in the Southern Ocean. In turn, we cannot pin down the problems for this region.&lt;/p&gt;

scholarly journals Dissolved iron in the North Atlantic Ocean and Labrador Sea along the GEOVIDE section (GEOTRACES section GA01)

2018 ◽  
Author(s):  
Manon Tonnard ◽  
Hélène Planquette ◽  
Andrew R. Bowie ◽  
Pier van der Merwe ◽  
Morgane Gallinari ◽  
...  
Keyword(s):  
Atlantic Ocean ◽  
North Atlantic ◽  
Sea Water ◽  
North Atlantic Ocean ◽  
Deep Convection ◽  
Labrador Sea ◽  
Intermediate Water ◽  
The North ◽  
Irminger Sea ◽  
The North Atlantic

Abstract. Dissolved Fe (DFe) samples from the GEOVIDE voyage (GEOTRACES GA01, May–June 2014) in the North Atlantic Ocean were analysed using a SeaFAST-picoTM coupled to an Element XR HR-ICP-MS and provided interesting insights on the Fe sources in this area. Overall, DFe concentrations ranged from 0.09 ± 0.01 nmol L−1 to 7.8 ± 0.5 nmol L−1. Elevated DFe concentrations were observed above the Iberian, Greenland and Newfoundland Margins likely due to riverine inputs from the Tagus River, meteoric water inputs and sedimentary inputs. Air-sea interactions were suspected to be responsible for the increase in DFe concentrations within subsurface waters of the Irminger Sea due to deep convection occurring the previous winter, that provided iron-to-nitrate ratios sufficient to sustain phytoplankton growth. Increasing DFe concentrations along the flow path of the Labrador Sea Water were attributed to sedimentary inputs from the Newfoundland Margin. Bottom waters from the Irminger Sea displayed high DFe concentrations likely due to the dissolution of Fe-rich particles from the Denmark Strait Overflow Water and the Polar Intermediate Water. Finally, the nepheloid layers were found to act as either a source or a sink of DFe depending on the nature of particles.

I.—On the Eastern Margin of the North Atlantic Basin

1899 ◽  
Vol 6 (3) ◽  
pp. 97-105 ◽  
Author(s):  
Wilfrid H. Hudleston
Keyword(s):  
North Atlantic ◽  
Physical Geography ◽  
Point Of View ◽  
Atlantic Basin ◽  
Eastern Margin ◽  
North Atlantic Basin ◽  
The North ◽  
The North Atlantic

In offering a few remarks on a subject which belongs, in the first instance, to the province of physical geography, it will be necessary forme to point out certain hydrographical details, whilst, endeavouring to deduce from these details conclusions having a geological bearing. Oceanography is almost a science in itself, especially if we regard it from a geological point of view, as something more than a mere description of water-spaces and soundings. Ever since the days when the deep oceans were first explored for the purpose of laying the telegraph cables some of the leading facts were made known, and have since become familiar to all students of physical geography.

4. Note on the Absorption of Sea-Water

1882 ◽  
Vol 11 ◽  
pp. 637-637
Author(s):  
John Aitken
Keyword(s):  
Absorption Band ◽  
Sea Water ◽  
Polarized Light ◽  
Selective Absorption ◽  
Regular Reflection ◽  
Surface Reflection ◽  
The Mediterranean ◽  
Mediterranean Water

In a letter to Professor Tait, dated Mentone, 14th April 1882, Mr. Aitken says :—Since coming here this time, I have tested the sea with the polariscope and with the spectroscope. With an instrument by Hoffman, which gives coloured bands with polarized light, I have been able to detect small, but decided indications of polarization in the light internally reflected by the water, the surface reflection being, of course, cut off when the observation was made. At present I think the polarization is due to regular reflection from the polished surfaces of some of the particles, which are seen to glance brightly in concentrated sunlight.I have also detected an absorption band in the green of the spectrum of the light internally reflected by the Mediterranean water. This band is much more distinct in water where there are but few reflecting particles, and the light undergoes a great amount of selective absorption.

scholarly journals Anthropogenic and natural CO<sub>2</sub> exchange through the Strait of Gibraltar

2009 ◽  
Vol 6 (4) ◽  
pp. 647-662 ◽  
Author(s):  
I. E. Huertas ◽  
A. F. Ríos ◽  
J. García-Lafuente ◽  
A. Makaoui ◽  
S. Rodríguez-Gálvez ◽  
...  
Keyword(s):  
Time Series ◽  
Atlantic Ocean ◽  
Mediterranean Sea ◽  
Mediterranean Basin ◽  
Inorganic Carbon ◽  
Strait Of Gibraltar ◽  
Anthropogenic Carbon ◽  
The Mediterranean ◽  
The Mediterranean Basin ◽  
Mediterranean Water

Abstract. The exchange of both anthropogenic and natural inorganic carbon between the Atlantic Ocean and the Mediterranean Sea through Strait of Gibraltar was studied for a period of two years under the frame of the CARBOOCEAN project. A comprehensive sampling program was conducted, which was design to collect samples at eight fixed stations located in the Strait in successive cruises periodically distributed through the year in order to ensure a good spatial and temporal coverage. As a result of this monitoring, a time series namely GIFT (GIbraltar Fixed Time series) has been established, allowing the generation of an extensive data set of the carbon system parameters in the area. Data acquired during the development of nine campaigns were analyzed in this work. Total inorganic carbon concentration (CT) was calculated from alkalinity-pHT pairs and appropriate thermodynamic relationships, with the concentration of anthropogenic carbon (CANT) being also computed using two methods, the ΔC* and the TrOCA approach. Applying a two-layer model of water mass exchange through the Strait and using a value of −0.85 Sv for the average transport of the outflowing Mediterranean water recorded in situ during the considered period, a net export of inorganic carbon from the Mediterranean Sea to the Atlantic was obtained, which amounted to 25±0.6 Tg C yr−1. A net alkalinity output of 16±0.6 Tg C yr−1 was also observed to occur through the Strait. In contrast, the Atlantic water was found to contain a higher concentration of anthropogenic carbon than the Mediterranean water, resulting in a net flux of CANT towards the Mediterranean basin of 4.20±0.04 Tg C yr−1 by using the ΔC* method, which constituted the most adequate approach for this environment. A carbon balance in the Mediterranean was assessed and fluxes through the Strait are discussed in relation to the highly diverse estimates available in the literature for the area and the different approaches considered for CANT estimation. This work unequivocally confirms the relevant role of the Strait of Gibraltar as a controlling point for the biogeochemical exchanges occurring between the Mediterranean Sea and the Atlantic Ocean and emphasizes the influence of the Mediterranean basin in the carbon inventories of the North Atlantic.

The reproductive biology of swordfish (Xiphias gladius) in the Strait of Gibraltar

2018 ◽  
Vol 99 (3) ◽  
pp. 649-659 ◽  
Author(s):  
Noureddine Abid ◽  
Amin Laglaoui ◽  
Abdelhay Arakrak ◽  
Mohammed Bakkali
Keyword(s):  
Mediterranean Sea ◽  
North Atlantic ◽  
Fork Length ◽  
Strait Of Gibraltar ◽  
Mixing Rate ◽  
The North ◽  
Lower Jaw ◽  
The North Atlantic ◽  
The Mediterranean ◽  
First Maturity

During the period from April to September for the years 2014–2016, 998 swordfishes caught by the Moroccan artisanal longline fishery in the Strait of Gibraltar were sampled to study the reproduction of this species in this mixing area between the Mediterranean Sea and the North Atlantic. The results showed that the sex ratio is slightly in favour of males for sizes smaller than 130 cm LJFL (Lower jaw-fork length), whereas females are more numerous in sizes larger than 140 cm LJFL. Fifty per cent of females were estimated to be mature at 170 cm LJFL, while for males, the size at first maturity was estimated to be 95 cm LJFL. The swordfish spawn from June to September, probably in the Mediterranean Sea. The findings of this study suggest that the reproductive characteristics of swordfish caught in the Strait of Gibraltar are similar to those of the Mediterranean swordfish, and a high mixing rate between the Mediterranean and the North Atlantic stocks occurs in the study area.

Northern source for Deglacial and Holocene deepwater composition changes in the Eastern North Atlantic Basin

2015 ◽  
Vol 425 ◽  
pp. 256-267 ◽  
Author(s):  
Janne Repschläger ◽  
Mara Weinelt ◽  
Nils Andersen ◽  
Dieter Garbe-Schönberg ◽  
Ralph Schneider
Keyword(s):  
North Atlantic ◽  
Atlantic Basin ◽  
North Atlantic Basin ◽  
Eastern North Atlantic ◽  
Composition Changes
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