Quantifying and understanding the processes driving turbulent mixing around Antarctica are key to closing the Southern Ocean's heat budget, an essential component of the global climate system. In 2016, a glider deployed in Ryder Bay, West Antarctic Peninsula, collected hydrographic and microstructure data, obtaining some of the first direct measurements of turbulent kinetic energy dissipation off West Antarctica. Elevated dissipation O(10⁻⁸) W kg⁻¹ is found above a topographic ridge separating the 520‐m‐deep bay, where values are O(10⁻¹⁰) W kg⁻¹, from a deep fjord of the continental shelf, suggesting the ridge is important in driving upward mixing of warm Circumpolar Deep Water. The 12 glider transects reveal significant temporal variability in hydrographic and dissipation conditions. Mooring‐based current and nearby meteorological data are used to attribute thermocline shoaling (deepening) to Ekman upwelling (downwelling) at Ryder Bay's southern boundary, driven by ∼3‐day‐long south‐westward (north‐westward) wind events. Anticyclonic winds generated near‐inertial shear in the bay's upper layers, causing elevated bay‐wide shear and dissipation ∼1.7 days later. High dissipation over the ridge appears to be controlled hydraulically, being co‐located (and moving) with steeply sloping isopycnals. These are observed in ∼60% of the transects, with a corresponding mean upward heat flux of ∼2.4 W m⁻². The ridge, therefore, provides sustained heat to the base of the thermocline, which can be released into overlying waters during the bay‐wide, thermocline‐focused dissipation events (mean heat flux of ∼1.3 W m⁻²). This highlights the role of ridges, which are widespread across the West Antarctic Peninsula, in the regional heat budget.

中文翻译：

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南极西部半岛沿海一带的湍流混合速率和机理

量化和了解驱动南极湍流混合的过程是关闭南大洋热量收支（全球气候系统的重要组成部分）的关键。2016年，部署在南极半岛西部莱德湾的滑翔机收集了水文和微观结构数据，获得了南极西部湍动能消散的首批直接测量值。在分隔520米深海湾的地形脊上方发现了较高的耗散O（10 ^-8）W kg ^-1，其值为O（10 ^-10）W kg ^-1，来自大陆架的深峡湾，表明该脊在推动温暖的环极深水向上混合中很重要。12个滑行样线揭示了水文和消散条件下的明显时间变化。基于系泊的当前和附近的气象数据被用来将莱因湾南部边界的埃克曼上升流（下降流）归因于约3天长的西南风（西北风）引起的热跃层浅入（加深）。反气旋风在海湾的上层产生了接近惯性的剪切力，导致大约1.7天后海湾的剪切力和消散力升高。脊上的高耗散似乎是通过液压控制的，与陡坡的等腰同位放在一起（并移动）。在大约60％的样线中可以观察到这些，⁻²。因此，山脊为热跃层的底部提供了持续的热量，在整个热跃层集中的海湾扩散事件（平均热通量约为1.3 W m ^-2）期间，热量可以释放到上覆的水中。这突显了在整个南极半岛上广泛分布的山脊在区域热量收支中的作用。