| A Hybrid Coordinate Ocean Model (HYCOM) is utilized to investigate the formation andevolution of pycnostads in the Japan/East Sea. The horizontal resolution of the simulation is .04 degrees (about 3.5 km) and there are 15 layers in the vertical. Inflow and outflowthrough the straits is prescribed via relaxation to climatology with an additional barotropiccomponent added. Interannual ECMWF winds and fluxes are used to force the surface. Verticalmixing occurs via a k-profile parameterization (KPP) scheme. Two primary mechanisms forthe formation of pycnostads (also known as Intra-thermocline eddies) are noted, althoughthese mechanisms are not mutually exclusive. The pycnostads are lens-shaped and characterized by relatively warm saline water . One mechanism is the restratification of the mixed layer on seasonal time scales. Here, warm saline water gets overridden by colder,less saline water, but the water that gets overridded maintains positive vorticity andhence forms pycnostads within the thermocline. The other mechanism for the formation of these features is frontal subduction of more saline water along the subpolar front. With this mechanism, localized pockets of warm saline water on the southern side of the subpolarfront are subducted beneath cooler less saline water on the northern side of the front, and the location of the pycnostads is determined by the location of meanders of the subpolarfront. |
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