A general circulation model is used to study the time evolution of a rotating, weakly baroclinic fluid in a basin with sloping sidewalls. Contours of f/h, where f is the Coriolis parameter and h is the depth of the fluid, are closed in this model. The fluid is forced by a localized source of positive vorticity. The initial response is a narrow, recirculating cell that resembles a β-plume modified by bathymetry. Such cells have been found in previous studies and have been linked to the recirculation cells observed in the subpolar North Atlantic. However, this is not a steady solution in a basin with closed f/h contours, and the circulation evolves into a gyre that encircles the basin. The timing of this evolution depends on the Rossby number, with higher Rossby numbers evolving faster. Based on the budget of potential vorticity, an argument is made that the western boundary is not long enough to drain significant vorticity from the flow and therefore a bathymetric βplume is not a steady solution. A similar argument suggests that the Labrador Sea cannot sustain steady, linear, barotropic recirculations either. We speculate that the observed recirculations depend on inertial separation at sharp bathymetric gradients to break the assumption of linearity, which leads to significant viscous dissipation.

中文翻译：

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具有封闭 f/h 轮廓的盆地中的再循环流

通用环流模型用于研究具有倾斜侧壁的盆地中旋转的弱斜压流体的时间演化。f/h 的等高线，其中 f 是科里奥利参数，h 是流体的深度，在该模型中是封闭的。流体受到局部正涡流源的推动。最初的反应是一个狭窄的循环细胞，类似于由测深法修改的 β 羽流。在之前的研究中已经发现了这种细胞，并与在北大西洋次极地观察到的再循环细胞有关。然而，在具有封闭 f/h 轮廓的盆地中，这不是一个稳定的解决方案，环流演变成一个环绕盆地的环流。这种演变的时间取决于罗斯比数，罗斯比数越高，进化得越快。根据位涡的预算，有一种观点认为，西部边界的长度不足以从流动中排出显着的涡度，因此测深 β 羽流不是稳定的解决方案。一个类似的论点表明，拉布拉多海也不能维持稳定的、线性的、正压再循环。我们推测观察到的再循环取决于在陡峭的测深梯度下的惯性分离，以打破线性假设，从而导致显着的粘性耗散。