Baía de Ilha Grande and Baía de Sepetiba are two connected coastal bays in southeastern Brazil just west of Rio de Janeiro. They are favored for tourism and recreation, provide most of the potable water for the city of Rio de Janeiro, are the site of the only two nuclear reactors in Brazil, a deep-water oil terminal, a Federal container port, and hundreds of industries. The bay system experiences mixed mainly semidiurnal tides and currents. Hundreds of sediment samples and cores plus side scan-sonar surveys were used to map the bottom sediment distribution. Long-term measurements from two moored instruments yielded two sets of time series of water level, currents, temperature, and salinity, which were used to analyze the salient ocean processes in the two bays. The temperature time series and extensive CTD profiling indicated the occurrence of cold-water intrusion events into Baía de Ilha Grande, with temperatures ranging from 16 °C to 20 °C, in spring to late summer (October–April). The intrusions are ascribed to coastal upwelling of South Atlantic Central Water as a result of synoptic northeasterly winds and the westward translation of cold core eddies and meanders from the region of Cabo Frio. The calculated mean sea level varies annually by 50 cm with a peak in June and a trough in November due to atmospheric pressure variations (5%), steric changes (28%), but mostly due to wind and Ekman effects. Spectral analysis was applied to analyze the water level and current time series. The results indicated both tidal asymmetry and the existence of a pronounced quarter-diurnal seiche oscillation in the coastal bay-system parallel to the coast.

巴伊亚格兰德岛和巴伊亚塞佩蒂巴岛是巴西东南部里约热内卢以西两个相连的沿海海湾。它们是旅游和休闲的理想之选，为里约热内卢市提供了大多数饮用水，是巴西仅有的两个核反应堆，深水石油码头，联邦集装箱港口和数百种工业的所在地。海湾系统主要经历半日潮和潮流混合。数以百计的沉积物样本和岩心以及侧面扫描声纳调查用于绘制底部沉积物分布图。从两个系泊仪器进行的长期测量得出了两组水位，水流，温度和盐度的时间序列，用于分析两个海湾的主要海洋过程。温度时间序列和广泛的CTD分析表明，春季至夏末（10月至4月），冷水入侵事件发生在大伊尔哈格兰德湾，温度范围为16°C至20°C。入侵归因于天气向北风和来自卡波弗里奥地区的冷核涡流和河曲向西平移的结果，是南大西洋中央水域的沿海上升。计算得出的平均海平面每年变化50厘米，由于气压变化（5％），空间变化（28％），但主要是由于风和埃克曼效应，每年6月达到高峰，11月进入低谷。应用频谱分析来分析水位和当前时间序列。