This study presents recent observations to quantify oceanic heat fluxes along the continental slope of the Eurasian part of the Arctic Ocean, in order to understand the dominant processes leading to the observed along‐track heat loss of the Arctic Boundary Current (ABC). We investigate the fate of warm Atlantic Water (AW) along the Arctic Ocean continental margin of the Siberian Seas based on 11 cross‐slope conductivity, temperature, depth transects and direct heat flux estimates from microstructure profiles obtained in summer 2018. The ABC loses on average (10⁸) J m⁻² per 100 km during its propagation along the Siberian shelves, corresponding to an average heat flux of 47 W m⁻² out of the AW layer. The measured vertical heat flux on the upper AW interface of on average 10 W m⁻² in the deep basin, and 3.7 W m⁻² above the continental slope is larger than previously reported values. Still, these heat fluxes explain less than 20% of the observed heat loss within the boundary current. Heat fluxes are significantly increased in the turbulent near‐bottom layer, where AW intersects the continental slope, and at the lee side of a topographic irregularity. This indicates that mixing with ambient colder water along the continental margins is an important contribution to AW heat loss. Furthermore, the cold halocline layer receives approximately the same amount of heat due to upward mixing from the AW, compared to heat input from the summer‐warmed surface layer above. This underlines the importance of both surface warming and increased vertical mixing in a future ice‐free Arctic Ocean in summer.

中文翻译：

---

北冰洋东部边界流沿坡的热损失

这项研究提出了最近的观测结果，以量化沿北冰洋欧亚大陆大陆坡的海洋热通量，以便了解导致观测到的北极边界流沿线热损失的主要过程。我们根据11个跨坡电导率，温度，深度断面和直接热通量估算得出的沿西伯利亚海的北冰洋大陆边缘的命运，该估算是根据2018年夏季获得的微观结构剖面得出的。沿西伯利亚大陆架传播的每100 km平均（10 ⁸）J m ^-2，对应于47 W m ^-2的平均热通量在AW层之外。在深水盆中，在上部AW界面上测得的垂直热通量平均为10 W m ^-2，而平均为3.7 W m ^-2大陆坡上方的高度大于先前报告的值。尽管如此，这些热通量解释了在边界电流内不到观察到的热损失的20％。在湍流的近底层（AW与大陆坡相交）以及地形不规则的背风侧，热通量显着增加。这表明与大陆边缘的环境较冷的水混合是造成AW热损失的重要因素。此外，与从上方的夏季加温表层输入的热量相比，冷盐水线层由于来自AW的向上混合而吸收的热量大致相同。这强调了在未来的未来无冰的北冰洋中，地表变暖和增加垂直混合的重要性。