A high‐resolution ocean model is used to characterize the circulation and cross‐shelf exchanges in the Brazilian/Uruguayan portion of the southwestern Atlantic shelf. Cross‐shelf exchanges are strongly modulated by the bottom topography. There is ∼1.2Sv of onshelf transport between 21°S and 25.2°S, and ∼1.6Sv of offshelf transport between 35°S and 25.2°S. North of 25.2°S the cross‐shelf exchanges show a two‐layer structure with an offshelf flow in the upper 50m and onshelf flow deep below. A Lagrangian diagnostic shows that ∼0.15Sv of deep waters from the Brazil Current (z > 200m) are injected into the shelf. Mixing with ambient waters produces a spicier (warmer and saltier) water mass, which is ejected into the open ocean in the southern region. Backward‐in‐time particle's trajectories analysis reveals that 95% of the southward shelf transport at 32°S originates in the open‐ocean at 22°S. Our model diagnostics show that there is a very limited connectivity between the shelf regions north and south of Cabo Frio. Correlation analysis shows no significant influence of ENSO and SAM on the time variability of the cross‐shelf transport. Cross‐shelf transports, however, are significantly correlated with the local wind stress variability.

中文翻译：

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西南大西洋北部陆架地区的环流和跨陆架交换：运动学

使用高分辨率海洋模型来表征西南大西洋大陆架巴西/乌拉圭部分的环流和跨架交换。跨架交换受到底部地形的强烈调制。在21°S和25.2°S之间有约1.2Sv的陆上运输，而在35°S和25.2°S之间有约1.6Sv的陆上运输。在25.2°S以北，跨架交换显示为两层结构，上部50m处有架空流，而下部深处则有架空流。拉格朗日诊断显示，来自巴西洋流（z> 200m）的约0.15Sv的深水被注入了陆架。与周围的水混合会产生较辣的（更温暖和更咸的）水团，然后将其喷入南部地区的公海中。时间倒退粒子” s的轨迹分析显示，在32°S的南向陆架运输中，有95％来自于22°S的远洋。我们的模型诊断结果显示，卡波弗里奥北部和南部的货架区域之间的连通性非常有限。相关分析表明，ENSO和SAM对跨架运输的时间变异性没有显着影响。但是，跨架运输与局部风应力变化具有显着的相关性。