Dow C F, Werder M A, Babonis G, Nowicki S, Walker R T, Csatho B, Morlighem M
Department of Geography and Environmental Management, University of Waterloo, Waterloo, ON, Canada.
Cryospheric Sciences Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD, USA.
J Geophys Res Earth Surf. 2018 Apr;123(4):837-850. doi: 10.1002/2017JF004409. Epub 2018 Mar 22.
Recovery Ice Stream has a substantial number of active subglacial lakes that are observed, with satellite altimetry, to grow and drain over multiple years. These lakes store and release water that could be important for controlling the velocity of the ice stream. We apply a subglacial hydrology model to analyze lake growth and drainage characteristics together with the simultaneous development of the ice stream hydrological network. Our outputs produce a good match between modeled lake location and those identified using satellite altimetry for many of the lakes. The modeled subglacial system demonstrates development of pressure waves that initiate at the ice stream neck and transit to within 100 km of the terminus. These waves alter the hydraulic potential of the ice stream and encourage growth and drainage of the subglacial lakes. Lake drainage can cause large R-channels to develop between basal overdeepenings that persist for multiple years. The pressure waves, along with lake growth and drainage rates, do not identically repeat over multiple years, due to basal network development. This suggests that the subglacial hydrology of Recovery Ice Stream is influenced by regional drainage development on the scale of hundreds of kilometers rather than local conditions over tens of kilometers.
复苏冰流有大量活跃的冰下湖泊，通过卫星测高法观测到这些湖泊在多年间有涨有落。这些湖泊储存和释放的水对于控制冰流速度可能很重要。我们应用一个冰下水文学模型来分析湖泊的生长和排水特征以及冰流水文网络的同步发展。我们的输出结果显示，对于许多湖泊而言，模拟的湖泊位置与利用卫星测高法确定的湖泊位置吻合度很高。模拟的冰下系统显示出压力波的发展，这些压力波始于冰流颈部，传播至距冰流终点100公里范围内。这些波改变了冰流的水力势，促进了冰下湖泊的生长和排水。湖泊排水会导致在基底过度深陷之间形成大型R形通道，这些通道会持续多年。由于基底网络的发展，压力波以及湖泊的生长和排水速率在多年间并非完全重复。这表明复苏冰流的冰下水文受到数百公里尺度上区域排水发展的影响，而非数十公里尺度上的局部条件的影响。
