Interactions between open-sea convection and shelf cascading dense waters in the formation of the Western Mediterranean Deep Water

Dynamics of Mediterranean deep waters, 27-30 May 2009, Malta.-- 9 pages, 5 figures
Sea-atmosphere interactions play an important role on the oceanographic processes at various spatial and temporal scales. In the Mediterranean Sea, several regions are key spots of intense airsea interactions which affect considerably the heat and water budgets. An example of this is the wintertime formation of dense water through interaction with the atmosphere, and further sinking by convection or cascading. The Gulf of Lions is one of the regions in the Mediterranean where massive dense water formation occurs because of cooling and evaporation of surface waters during winter-time. Concurrent with the well known open-sea convection process over the MEDOC region, coastal surface waters over the wide shelf of the Gulf of Lions also become denser than the underlying waters and cascade downslope until reaching their equilibrium depth. Through this climate-driven phenomenon, dense shelf waters carrying large quantities of particles in suspension are rapidly advected hundreds of meters deep, mainly through submarine canyons. Recent observations within the frame of several research initiatives conducted in the north-western Mediterranean indicate that major dense shelf water cascades from the Gulf of Lions have a direct effect on the Western Mediterranean Deep Water (WMDW) thermohaline properties and are responsible for the formation of a thick and persistent bottom nepheloid layer (BNL) that spreads throughout the western Mediterranean basin and scales in thickness with the WMDW anomaly created during sever winters like those of 1999 and 2005
This research was supported by the EuroSTRATAFORM Program funded by the ONR (contract N00014-04-1-0379) and by the EC 5th FP (project EVK3-2002-00079). Additional support was obtained from the HERMES Project funded by the EC 6th FP (contract GOCE-CT-2005-511234) and by the project EFLUBIO funded by the Spanish Ministry of Education and Science (Ref: REN2002-04151-C02-01/MAR). The HC-ICM mooring turnaround was also supported by the Spanish Ministry of Education and Science (Ref: CTM2007-28881-E)