This study investigates the impact of glacial water discharges on the hydrodynamics of a glacial bay in Antarctica, comparing it to well-studied northern hemisphere fjords. The research was carried out in Admiralty Bay (AB) in the South Shetland Islands, a wide bay adjacent to twenty marine-terminating glaciers. From December 2018 until February 2023, AB water properties were measured on 136 days. This dataset showed that a maximally two-layered stratification occurs in AB and that glacial water is always the most buoyant water mass. Using the Delft3D Flow, a three-dimensional hydrodynamical model of AB was developed. During tests, the vertical position and initial velocity of glacial discharges have been shown to be insignificant for the overall bay circulation. Fourteen model scenarios have been calculated with an increasing glacial influx added. The AB general circulation pattern consists of two cyclonic cells. Even in scenarios with significant glacial input, water level shifts and circulation are predominantly controlled by the ocean. Glacial freshwater is carried out of AB along its eastern boundary in a surface layer. Freshwater thickness in this outflow current is maximally 0.27-0.35 m. Within the inner AB inlets, significant glacial influx produces buoyancy-driven vertical circulation. Using an approach combining hydrographic and modeling data, a four-year timeseries of glacial influx volumes into AB has been produced. On average, glacial influx in summer is 10 times greater than in spring and winter and 3 times higher than in autumn. The annual glacial influx into AB was estimated at 0.434-0.632 Gt. Overall, the study demonstrated the unique characteristics of the topography and forcings that influence the hydrodynamics of an Antarctic glacial bay.

中文翻译：

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冰川流入对南极洲金钟湾水动力的影响——基于水文测量和数值模拟相结合的研究

这项研究调查了冰川水排放对南极洲冰川湾流体动力学的影响，并将其与经过充分研究的北半球峡湾进行了比较。这项研究是在南设得兰群岛的金钟湾 (AB) 进行的，这是一个毗邻 20 条海洋终止冰川的宽阔海湾。从2018年12月到2023年2月，对AB水性能进行了136天的测量。该数据集表明，AB 区域发生最大两层分层，并且冰川水始终是最具浮力的水团。使用 Delft3D Flow，开发了 AB 的三维流体动力学模型。在测试过程中，冰川放电的垂直位置和初始速度已被证明对于整个海湾环流来说并不重要。计算了十四种模型情景，并添加了不断增加的冰川流入。 AB 大气环流模式由两个气旋单元组成。即使在有大量冰川输入的情况下，水位变化和环流也主要由海洋控制。冰川淡水沿着 AB 的表层东部边界被带出。该流出流中的淡水厚度最大为0.27-0.35 m。在内 AB 入口内，大量冰川流入产生浮力驱动的垂直环流。使用水文学和建模数据相结合的方法，生成了 AB 冰川流入量的四年时间序列。平均而言，夏季冰川流入量是春季和冬季的10倍，是秋季的3倍。每年流入 AB 的冰川量估计为 0.434-0.632 Gt。总体而言，该研究证明了影响南极冰川湾流体动力学的地形和强迫的独特特征。