Advanced Ocean Modelling: Using Open-Source Software

138 5 3D Level Modelling5.5.2 Mediterranean SeasMediterranean seas are semi-enclosed bodies of water that have a limited exchangeof deep water with the ambient ocean and where the water circulation is dominatedby salinity and temperature differences rather than wind forcing. The exchange withthe adjacent ocean is constrained by a narrow strait often in conjunction with shallowerwater depth associated with a sill.Mediterranean seas of the Atlantic Ocean are the Eurafrican Mediterranean Seaincluding various sub-seas such as the Adriatic Sea and the Black Sea, the ArcticOcean, the American Mediterranean Sea that includes the Gulf of Mexico and theCarrabian Sea, and the Baltic Sea. Mediterranean seas of the Indian Ocean are thePersian Gulf and the Red Sea, and the Australasian Mediterranean Sea, includingthe Banda, Sulu, Sulawesi and Java Seas, being connected with the Pacific Ocean.See (Tomczak and Godfrey, 2003) for more details.Mediterranean seas share characteristics of estuaries, but the latter are generallymuch shallower and narrower including gulfs and seaward portions of rivers. Somescientists including the author prefer to classify the Baltic Sea and the Persian Gulfas estuaries.Mediterranean seas receiving more freshwater via continental runoff and directprecipitation than they lose by evaporation are called dilution basins and are found inhumid climatic zones. The surplus of freshwater in these systems creates an outflowof low-salinity water in the surface layer and an inflow of oceanic water in the lowerlayer (Fig. 5.10a). On the other hand, concentration basins experience a net freshwaterloss owing to excessive evaporation and are situated in arid climatic zones.The loss of freshwater from these systems leads to an outflow of saline sub-surfaceFig. 5.10 The circulation of mediterranean seas for (top panel) dilution basins and (bottom panel)concentration basins