Surface Expression of a Wall Fountain: Application to Subglacial Discharge Plumes
Surface Expression of a Wall Fountain: Application to Subglacial Discharge Plumes
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DOI：
10.1175/jpo-d-19-0213.1
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发表时间：
2019-03
影响因子：
3.5
通讯作者：
C. McConnochie;C. Cenedese;J. McElwaine
中科院分区：
文献类型：
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作者：
C. McConnochie;C. Cenedese;J. McElwaine
我们使用实验室实验和理论模型来研究冰下放电羽流的表面表达，就像格陵兰岛周围许多峡湾所发生的那样。实验考虑了一个喷泉，它垂直释放到与垂直或倾斜的墙壁相邻的均匀流体中，然后在下沉到底部之前在自由表面水平扩散。我们提出了一个模型，将喷泉分为两个独立的区域：一个垂直的喷泉和一个水平的负浮力射流。该模型与在一系列体积通量、密度差和环境流体深度下进行的实验室实验进行了比较。结果表明，表面表达式的无量纲长度、宽度和纵横比取决于在负浮力射流开始时计算的弗劳德数。该模型应用于格陵兰岛冰下排放羽流表面表达的观测。在排放羽流以负浮力到达表面的情况下，该模型可用于估计冰川底部的排放特性。
We use laboratory experiments and theoretical modeling to investigate the surface expression of a subglacial discharge plume, as occurs at many fjords around Greenland. The experiments consider a fountain that is released vertically into a homogeneous fluid, adjacent either to a vertical or a sloping wall, that then spreads horizontally at the free surface before sinking back to the bottom. We present a model that separates the fountain into two separate regions: a vertical fountain and a horizontal, negatively buoyant jet. The model is compared to laboratory experiments that are conducted over a range of volume fluxes, density differences, and ambient fluid depths. It is shown that the nondimensionalized length, width, and aspect ratio of the surface expression are dependent on the Froude number, calculated at the start of the negatively buoyant jet. The model is applied to observations of the surface expression from a Greenland subglacial discharge plume. In the case where the discharge plume reaches the surface with negative buoyancy the model can be used to estimate the discharge properties at the base of the glacier.