Enceladus is believed to have a saltwater global ocean, heated at the ocean–core interface and losing heat to the floating ice shell above. This configuration suggests an important role for vertical convection. The ice shell has dramatic meridional thickness variations that, in steady state, must be sustained by the ocean circulation against processes acting to remove these anomalies. This could be achieved through spatially separated regions of freezing and melting at the ocean–ice interface. Here, we use an idealized, dynamical ocean model forced by an observationally guided density flux at the ocean–ice interface to argue that Enceladus’s interior ocean should support a meridional overturning circulation. This circulation establishes an interior density structure that is more complex than in studies that have focused only on vertical convection, including a shallow freshwater lens in the polar regions. Spatially separated sites of ice formation and melt enable Enceladus to sustain significant vertical and horizontal stratification, which influences interior heat transport and is critical for understanding the relationship between a global ocean and the planetary energy budget. On the basis of our model, the presence of low salinity layers near the polar ocean–ice interface implies the ocean’s bulk salinity could substantially exceed values inferred from Cassini plume samples.

土卫二被认为有一个咸水全球海洋，在海洋-核心界面处加热，并将热量散失给上面的浮冰壳。这种配置表明垂直对流的重要作用。冰壳具有显着的经向厚度变化，在稳定状态下，必须由海洋环流维持，以对抗消除这些异常的过程。这可以通过在海冰界面处空间分离的冻结和融化区域来实现。在这里，我们使用由观测引导的海冰界面密度通量强制的理想化动态海洋模型来论证土卫二的内部海洋应该支持经向翻转环流。这种循环建立了一个内部密度结构，比只关注垂直对流的研究更复杂，包括极地地区的浅淡水透镜体。冰形成和融化的空间分离地点使土卫二能够维持显着的垂直和水平分层，这会影响内部热量传输，对于理解全球海洋与行星能量收支之间的关系至关重要。根据我们的模型，极地海冰界面附近存在低盐度层意味着海洋的整体盐度可能大大超过从卡西尼羽流样本推断的值。它影响内部热量传输，对于理解全球海洋与行星能量收支之间的关系至关重要。根据我们的模型，极地海冰界面附近存在低盐度层意味着海洋的整体盐度可能大大超过从卡西尼羽流样本推断的值。它影响内部热量传输，对于理解全球海洋与行星能量收支之间的关系至关重要。根据我们的模型，极地海冰界面附近存在低盐度层意味着海洋的整体盐度可能大大超过从卡西尼羽流样本推断的值。