scholarly journals Observations of new western Mediterranean deep water formation using Argo floats 2004–2006

Ocean Science ◽  
2008 ◽  
Vol 4 (2) ◽  
pp. 133-149 ◽  
Author(s):  
R. O. Smith ◽  
H. L. Bryden ◽  
K. Stansfield
Keyword(s):  
Mediterranean Sea ◽  
Deep Water ◽  
Temperature Increase ◽  
Deep Convection ◽  
Western Mediterranean ◽  
Deep Water Formation ◽  
Western Basin ◽  
Water Formation ◽  
Salinity Increase ◽  
Mixed Layers

Abstract. The deep convection that occurs in the western basin of the Mediterranean Sea was investigated using Argo float data over two consecutive winters in 2004–2005 and 2005–2006. The results showed deep mixed layers reaching 2000 m in surprising locations, namely the eastern Catalan subbasin (39.785° N, 4.845° E) and the western Ligurian subbasin (43.392° N, 7.765° E). Subsequently, new deep water was formed in March of 2005 and 2006 with θ=12.89–12.92°C, S=38.48–38.49 and σθ=29.113 kg m−3. The deep water produced in the Ligurian subbasin during 2006 was more saline, warmer and denser than any historical observations of western Mediterranean deep water. The results show S, θ and σθ in the western Mediterranean deep water are higher than 1990s values, with a salinity increase of 1.5×10−3 yr−1, a temperature increase of 3.6×10−3 °C yr−1 and a density increase of 4.0×10−4 kg m−3 yr−1 apparent from a dataset of western Mediterranean deep water properties spanning 1955–2006.

scholarly journals Observations of new western Mediterranean deep water formation using ARGO floats 2004–2006

2007 ◽  
Vol 4 (5) ◽  
pp. 733-783 ◽  
Author(s):  
R. O. Smith ◽  
H. L. Bryden
Keyword(s):  
Mediterranean Sea ◽  
Deep Water ◽  
Temperature Increase ◽  
Deep Convection ◽  
Western Mediterranean ◽  
Deep Water Formation ◽  
Western Basin ◽  
Water Formation ◽  
Salinity Increase ◽  
Mixed Layers

Abstract. The deep convection that occurs in the western basin of the Mediterranean Sea was investigated using ARGO float data over two consecutive winters in 2004–2005 and 2005–2006. The results showed deep mixed layers reaching 2000 m in surprising locations, namely the eastern Catalan subbasin (39.785° N, 4.845° E) and the western Ligurian subbasin (43.392° N, 7.765° E). Subsequently, new deep water was formed in March of 2005 and 2006 with θ=12.89–12.92°C, S=38.48–38.49 and σθ=29.113 kg m−3. The deep water produced in the Ligurian subbasin during 2006 was more saline, warmer and denser than any historical observations of Western Mediterranean Deep Water. The results show S, θ and σθ in the Western Mediterranean Deep Water are higher than 1990s values, with a salinity increase of 1.5×10−3 yr−1, a temperature increase of 3.6×10−3°C yr−1 and a density increase of 4.0×10−4 kg m−3 yr−1 apparent from a dataset of WMDW properties spanning 1955–2006.

scholarly journals Will deep water formation collapse in the North Western Mediterranean Sea by the end of the 21st century?

2021 ◽  
Author(s):  
Iván Manuel Parras Berrocal ◽  
Ruben Vazquez ◽  
William David CabosNarvaez ◽  
Dimitry Sein ◽  
Oscar Alvarez Esteban ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
21St Century ◽  
Deep Water ◽  
Western Mediterranean ◽  
Deep Water Formation ◽  
The North ◽  
Western Mediterranean Sea ◽  
Water Formation ◽  
North Western

scholarly journals Changes in ventilation of the Mediterranean Sea during the past 25 year

Ocean Science ◽  
2014 ◽  
Vol 10 (1) ◽  
pp. 1-16 ◽  
Author(s):  
A. Schneider ◽  
T. Tanhua ◽  
W. Roether ◽  
R. Steinfeldt
Keyword(s):  
Mediterranean Sea ◽  
Deep Water ◽  
Adriatic Sea ◽  
Western Mediterranean ◽  
Tyrrhenian Sea ◽  
Deep Water Formation ◽  
Technical Problems ◽  
Water Formation ◽  
The Mediterranean ◽  
Transient Tracer

Abstract. Significant changes in the overturning circulation of the Mediterranean Sea has been observed during the last few decades, the most prominent phenomena being the Eastern Mediterranean Transient (EMT) in the early 1990s and the Western Mediterranean Transition (WMT) during the mid-2000s. During both of these events unusually large amounts of deep water were formed, and in the case of the EMT, the deep water formation area shifted from the Adriatic to the Aegean Sea. Here we synthesize a unique collection of transient tracer (CFC-12, SF6 and tritium) data from nine cruises conducted between 1987 and 2011 and use these data to determine temporal variability of Mediterranean ventilation. We also discuss biases and technical problems with transient tracer-based ages arising from their different input histories over time; particularly in the case of time-dependent ventilation. We observe a period of low ventilation in the deep eastern (Levantine) basin after it was ventilated by the EMT so that the age of the deep water is increasing with time. In the Ionian Sea, on the other hand, we see evidence of increased ventilation after year 2001, indicating the restarted deep water formation in the Adriatic Sea. This is also reflected in the increasing age of the Cretan Sea deep water and decreasing age of Adriatic Sea deep water since the end of the 1980s. In the western Mediterranean deep basin we see the massive input of recently ventilated waters during the WMT. This signal is not yet apparent in the Tyrrhenian Sea, where the ventilation seems to be fairly constant since the EMT. Also the western Alboran Sea does not show any temporal trends in ventilation.

scholarly journals Characterizing, modelling and understanding the climate variability of the deep water formation in the North-Western Mediterranean Sea

2016 ◽  
Vol 51 (3) ◽  
pp. 1179-1210 ◽  
Author(s):  
Samuel Somot ◽  
Loic Houpert ◽  
Florence Sevault ◽  
Pierre Testor ◽  
Anthony Bosse ◽  
...  
Keyword(s):  
Climate Variability ◽  
Mediterranean Sea ◽  
Deep Water ◽  
Western Mediterranean ◽  
Deep Water Formation ◽  
The North ◽  
Western Mediterranean Sea ◽  
Water Formation ◽  
North Western

scholarly journals Changes in ventilation of the Mediterranean Sea during the past 25 yr

2013 ◽  
Vol 10 (4) ◽  
pp. 1405-1445 ◽  
Author(s):  
A. Schneider ◽  
T. Tanhua ◽  
W. Roether ◽  
R. Steinfeldt
Keyword(s):  
Mediterranean Sea ◽  
Deep Water ◽  
Adriatic Sea ◽  
Western Mediterranean ◽  
Tyrrhenian Sea ◽  
Deep Water Formation ◽  
Overturning Circulation ◽  
Water Formation ◽  
The Mediterranean ◽  
Transient Tracer

Abstract. The Mediterranean Sea has a fast overturning circulation and the deep water masses are well ventilated in comparison to the deep waters of the world ocean. Significant changes in the overturning circulation has been observed during the last few decades, the most prominent phenomena being the Eastern Mediterranean Transient (EMT) in the early 1990s and the Western Mediterranean Transit (WMT) near the mid of the decade following. During both of these events unusually large amounts of deep water were formed, and in the case of the EMT, the deep water formation area shifted from the Adriatic to the Aegean Sea. This variability is important to understand and to monitor, because ventilation is the main process to propagate surface perturbations, such as uptake of anthropogenic CO2, into the ocean interior. Here we synthesize a unique collection of transient tracer (CFC-12, SF6 and tritium) data from nine cruises conducted between 1987 and 2011 and use these data to determine temporal variability of Mediterranean ventilation. We also discuss biases and technical problems with transient tracer-based ages arising from their different input histories over time; particularly in the case of time-dependent ventilation. We observe a period of stagnation in the deep eastern (Levantine) basin after it was ventilated by the EMT so that the age of the deep water is increasing with time. In the Ionian Sea, on the other hand, we see evidence of increased ventilation after year 2001, indicating the restarted deep water formation in the Adriatic Sea. This is also reflected in the increasing age of the Cretan Sea deep water and decreasing age of Adriatic Sea deep water since the end of the 1980s. In the western Mediterranean deep basin we see the massive input of recently ventilated waters during the WMT. This signal is not yet apparent in the Tyrrhenian Sea, where the ventilation seems to be fairly constant since the EMT. Also the western Alboran Sea does not show any temporal trends in ventilation.

scholarly journals North Atlantic deep water formation and AMOC in CMIP5 models

Ocean Science ◽  
2017 ◽  
Vol 13 (4) ◽  
pp. 609-622 ◽  
Author(s):  
Céline Heuzé
Keyword(s):  
Sea Ice ◽  
Ocean Circulation ◽  
North Atlantic ◽  
Deep Water ◽  
Deep Convection ◽  
The Arctic ◽  
Subpolar Gyre ◽  
Deep Water Formation ◽  
Nordic Seas ◽  
Water Formation

Abstract. Deep water formation in climate models is indicative of their ability to simulate future ocean circulation, carbon and heat uptake, and sea level rise. Present-day temperature, salinity, sea ice concentration and ocean transport in the North Atlantic subpolar gyre and Nordic Seas from 23 CMIP5 (Climate Model Intercomparison Project, phase 5) models are compared with observations to assess the biases, causes and consequences of North Atlantic deep convection in models. The majority of models convect too deep, over too large an area, too often and too far south. Deep convection occurs at the sea ice edge and is most realistic in models with accurate sea ice extent, mostly those using the CICE model. Half of the models convect in response to local cooling or salinification of the surface waters; only a third have a dynamic relationship between freshwater coming from the Arctic and deep convection. The models with the most intense deep convection have the warmest deep waters, due to a redistribution of heat through the water column. For the majority of models, the variability of the Atlantic Meridional Overturning Circulation (AMOC) is explained by the volumes of deep water produced in the subpolar gyre and Nordic Seas up to 2 years before. In turn, models with the strongest AMOC have the largest heat export to the Arctic. Understanding the dynamical drivers of deep convection and AMOC in models is hence key to realistically forecasting Arctic oceanic warming and its consequences for the global ocean circulation, cryosphere and marine life.

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