The formation of western Mediterranean Deep Water

Author(s):  
Kevin D. Leaman
2012 ◽  
Vol 55 (5) ◽  
Author(s):  
Sergi Joher ◽  
Enric Ballesteros ◽  
Emma Cebrian ◽  
Noemí Sánchez ◽  
Conxi Rodríguez-Prieto

Hydrobiologia ◽  
2011 ◽  
Vol 670 (1) ◽  
pp. 67-85 ◽  
Author(s):  
Beatriz Guijarro ◽  
George Tserpes ◽  
Joan Moranta ◽  
Enric Massutí

2010 ◽  
Vol 7 (4) ◽  
pp. 1533-1557
Author(s):  
W. Roether ◽  
J. E. Lupton

Abstract. Observations of tritium and 3He in the Tyrrhenian Sea, 1987–2009, confirm the enhanced convective mixing of intermediate waters into the deep waters that has been noted and associated with the Eastern Mediterranean Transient in previous studies. Our evidence for the mixing rests on increasing tracer concentrations in the Tyrrhenian deep waters, accompanied by decreases in the upper waters, which are supplied from the Eastern Mediterranean. The downward transfer is particularly evident between 1987 and 1997. Later on, information partly rests on increasing tritium-3He ages; here we correct the observed 3He for contributions released from the ocean floor. The Tyrrhenian tracer distributions are fully compatible with data upstream of the Sicily Strait and in the Western Mediterranean. The tracer data show that mixing reached to the bottom and confirm a cyclonic nature of the deep water circulation in the Tyrrhenian. They furthermore indicate that horizontal homogenization of the deep waters occurs on a time scale of several years. Various features point to a reduced impact of Western Mediterranean Deep Water (WMDW) in the Tyrrhenian during the enhanced-convection period. This is an important finding because it implies less upward mixing of WMDW, which has been named a major process to enable the WMDW to leave the Mediterranean via the Gibraltar Strait. On the other hand, the TDW outflow for several years represented a major influx of enhanced salinity and density waters into the deep-water range of the Western Mediterranean.


Ocean Science ◽  
2008 ◽  
Vol 4 (2) ◽  
pp. 133-149 ◽  
Author(s):  
R. O. Smith ◽  
H. L. Bryden ◽  
K. Stansfield

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.


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