3:45 PM - 4:00 PM
[MIS10-02] Dynamics of the Atlantic meridional overturning circulation and Southern Ocean in an ocean model of intermediate complexity
Keywords:Oceanic deep circulation, Layer model, Southern Ocean
A hierarchy of solutions is obtained in which forcings and processes are individually introduced. The complete solution set includes a wide variety of solution types: with sinking in the northern North Atlantic and with sinking near Antarctica; with and without wind forcing; with, without, and for two parameterizations of northern-boundary sinking that represent cooling external to and within the North Atlantic; for a wide range of mesoscale-eddy mixing strength and wind stress in the Antarctic Circumpolar region; and for different closures for mesoscale-eddy mixing. Novel aspects of the model and solutions include the following: use of VLOM, which allows buoyancy forcing to be introduced realistically; the aforementioned closure, which allows eddy-induced transport to be determined when layer 1 represents _both_ the surface mixed layer (h=h_m) and the depth of subsurface isopycnals (h>h_m); latitude where layer 1 outcrops in the Southern Ocean being _internally_ determined rather than externally specified; and a boundary layer, based on Gill's (1968) solution, that smoothly connects the Southern- and Atlantic-Ocean responses across the latitude of the southern tip of South America. Finally, some solutions in the set are comparable to solutions to idealized, ocean general circulation models (OGCMs); in these cases, our solutions provide insight into the underlying dynamics of the OGCM solutions, for example, pointing toward processes that may be involved in eddy saturation and compensation.