The plumes from the rivers of the South Brazilian Bight (SBB) and South Brazil (SB) were studied using a realistic model configuration. River plume variability on continental shelves is driven by the input of river runoff into the shelf, by wind variability, and also by ambient currents and its seasonal variability, especially the Brazil Current, which are realistically modelled in this study. It is presented a simulation of 4 years using a nested configuration, which allows resolving the region around Florianópolis with very high resolution (∼150 m). The dispersion of river plumes was assessed not only with the hydrodynamical model results but also by using passive tracers whose dynamics was analyzed seasonally. Several dyes were released together with the river discharges. This approach allowed calculating the depths of the riverine freshwater, and the resulting regions affected by the plumes. Northward intrusions of waters from the southern region, under the potential influence of the distant La Plata river plume, were evaluated with a Lagrangian approach. The local river plumes are confined to the inner shelf, except south of 30°S where discharges from Lagoa dos Patos disperse over the shelf in the spring and summer. The Brazil Current flowing southward over the slope prevents the river plumes from interaction with oceanic mesoscale dynamics. The river plumes are, thus, mainly controlled by the wind forcing. The plumes from SBB are able to disperse until SB following the southward wind regime typical of the summer. And both the SB and La Plata river plumes are also able to reach SBB, forced by the northward wind typical of the winter season, until the latitude of 25.5°S. A low salinity belt (below 35) is present along the coastal region of SB and SBB year-round, supported by contributions from both the large and small rivers. The interaction between the different plumes influences the dispersion patterns, shielding the Florianṕolis coastal region from plumes of distant rivers, and dispersing the plume of SBB rivers away from Santa Catarina Island as it disperses southward during the summer months.

使用实际模型配置研究了来自巴西南部海岸线（SBB）和巴西南部（SB）河流的羽流。大陆架上的河羽变化性是由河流径流输入到架子上，受风的变化性以及环境水流及其季节变化（尤其是巴西洋流）驱动的，在本研究中它们是实际建模的。它使用嵌套配置进行了为期4年的模拟，可以高分辨率解析（〜150 m）的Florianópolis地区。不仅利用流体动力学模型结果评估了河羽的扩散，而且还使用了被动式示踪剂，对它们进行了季节性分析。几种染料与河水一起被释放。这种方法可以计算河流淡水的深度，以及由此产生的区域受到羽流的影响。在拉普拉塔河羽流的潜在影响下，采用拉格朗日方法评估了来自南部地区的水向北入侵。除了在南纬30°以南，春季和夏季，Lagoa dos Patos的排泄物分散在整个架子上，当地的河羽被限制在内部架子上。在斜坡上向南流动的巴西洋流阻止了河中的羽流与海洋中尺度动力相互作用。因此，河羽主要受风力控制。SBB的羽流能够按照夏季典型的向南风势散布到SB。在冬季典型的北风的作用下，SB和La Plata河的烟流也都能够到达SBB，直到纬度为25.5°S。SB和SBB沿海地区全年都有低盐度带（低于35），这得益于大小河流的贡献。不同羽流之间的相互作用会影响散布模式，使Florianṕolis沿海地区免受远处河水的羽流的影响，并在夏季月份向南扩散时，将SBB河流的烟羽散布到圣卡塔琳娜岛之外。