The present study aims to research the physico-chemical processes in two under-researched coastal systems located on the west and south Portuguese coast—Mira Estuary and Ria de Alvor—through the development and exploitation of dedicated coupled physical and water quality models. Both systems are highly dynamic, supporting a wide range of biological diversity; however, they are characterized by distinct environmental and oceanographic conditions, enhancing the importance of a comparative approach. In this context, the Delft3D modeling suite was implemented and successfully calibrated and validated for both systems, accurately reproducing their hydrodynamic, hydrographic, and chemical features. A broad characterization of Mira Estuary and Ria de Alvor was carried out. Results show that the tidal wave interacts differently with the different geomorphology of each estuary. The tidal wave amplitude decreases as it propagates upstream for both estuaries; however, the magnitude for Ria de Alvor is higher. A flood tidal dominance was found for Mira Estuary, allowing the transport of well-oxygenated water into the estuary, contributing to high residence times in the middle estuary and therefore to poor dissolved oxygen (DO) replenishment. Ria de Alvor shifts from ebb dominance at the central area to flood dominance upstream with low residence times, allowing an effective exchange of water properties. Results also reveal that the water temperature is the dominant driver of seasonal dissolved oxygen variations in both estuaries, with the lowest levels occurring during the late summer months when the water temperature is highest. In addition, pH is influenced by biological activity and freshwater inflow.

中文翻译：

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两种葡萄牙沿海系统的理化特性：Ria de Alvor和Mira Estuary

本研究旨在通过开发和开发专用的物理和水质耦合模型，研究位于葡萄牙西部和南部海岸的两个未研究的沿海系统（米拉河口和Ria de Alvor）的物理化学过程。这两个系统都是高度动态的，支持广泛的生物多样性。然而，它们的特点是独特的环境和海洋条件，增强了比较方法的重要性。在这种情况下，Delft3D建模套件已实现并成功针对两个系统进行了校准和验证，从而准确地再现了它们的水动力，水文和化学特征。对Mira河口和Ria de Alvor进行了广泛的表征。结果表明，潮汐与每个河口的不同地貌有不同的相互作用。潮汐波幅随着向两个河口的上游传播而减小。但是，Ria de Alvor的震级更高。在Mira河口发现了洪水潮汐优势，使含氧量良好的水运入河口，这导致河口在中段停留时间较长，从而导致溶解氧（DO）补充不足。里亚德·阿尔沃（Ria de Alvor）从中心地区的落潮主导向低滞留时间的上游洪水主导转变，实现了水质的有效交换。结果还表明，水温是两个河口季节性溶解氧变化的主要驱动因素，在夏季最高水温最高的月份出现最低水平。此外，pH值还受生物活性和淡水流入的影响。