Advanced Ocean Modelling: Using Open-Source Software

148 5 3D Level ModellingFig. 5.17 Schematic of the deep-ocean circulation in the Atlantic Ocean after Stommel (1958)using GEBCO (General Bathymetric Chart of the Oceans) data5.8 Exercise 24: The Abyssal Circulation5.8.1 AimThe aim of this exercise is to explore the dynamics of the deep circulation establishingin a closed ocean basin on the beta plane.5.8.2 Task DescriptionWe consider a model domain of 1,000 × 1,000 km in horizontal extent (Fig. 5.18),resolved by lateral grid spacings of Δx = Δy = 20 km, and a constant total depthof 1,000 m, resolved by a vertical grid spacing of Δz = 200 m. The ocean is initiallyat rest and uniform in density with ρ = 1,028 km/m 3 . The model domain includes aseparate semi-enclosed region of 200 × 200 km in horizontal dimension mimickinga region of dense-water formation such as the Greenland Sea or the Labrador Sea inthe real situation. The model is forced by prescription of a density flux of 1 kg/m 3 per30 days applied to the entire water column north of y = 880 km. This forcing ismaintained during the entire model simulation lasting 120 days with data outputson a daily basis.