| A series of numerical experiments have been performed using a regionalmodel of the sub-polar North Atlantic. A partial cell topographic representationis used to improve circulation pathways in the Labrador Sea (including pathwaysof the Labrador Current) and to modify theformation locations and properties of sub-polar mode water and Labrador Sea Water (LSW).An unexpected result of the partial cell topographic representation is a markeddecrease of the freshwater content of the Labrador Sea during the earlystages of the integrations, leading to the model forming overly salty and dense LSW.The main components of this change is a greaterimport of high salinity water from the North Atlantic current and the enhanced export ofLabrador Sea Water directly to the Irminger Sea. Both of these transports are primarily related to thepresence of a strong Labrador Sea counter-current in the partial cell simulation.One striking feature associated with the generation of the counter-currentis a very large amount of eddy activity. A brief energy analysis, including examining the time-rates ofconversion between the different types of energies,suggests that the increased production of eddies in the partial cell experimentis at least partly due to enhanced baroclinic instability occurring infrontal regions. Additionally, a conversion of eddy kinetic energy into mean kineticenergy that only occurs in the partial cell experiment suggests that the Labrador Seacounter-current may be part driven by these eddies.Ongoing experiments are examining the role of eddy-parameterizations in the modeland implementation of a spatially varying eddy-transfer coefficient. These suggestan improvement in the model representation of the Deep Western Boundary Current in theLabrador Sea.A flux forced version of the model has also been produced andresults suggest the importance of the air-sea interaction in producing thecold intermediate layer along the Labrador shelf. |
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