New 3D model of Store Glacier explains complex behaviour of Greenland’s marine-terminating outlets

Our project has created what is perhaps the most sophisticated 3D model of a glacier today. Our model is presented in full-Stokes 3D and features evolving hydrological systems, plume-induced melting at the submerged glacier front and iceberg calving. When the model is applied to Store Glacier (Sermeq Kujalleq) we found significant differences in behaviour during warm and cold years. In warm summers, we found a system of large subglacial channels to develop fully and extend 41 km inland from the calving margin. In cold summers, however, the channelised system formed only partially, with channels extending only 29 km inland. Farther inland, we found a hydrodynamic feedback to suppress the channels growth, resulting in storage of water in a widespread and distributed system of cavities instead. At the terminus, we found hydrodynamic feedbacks exert a major control on calving through their impact on the glacier’s flow and velocity. This contrast in modelled behaviour shows that tidewater glaciers such as Store can experience a strong hydrological, as well as oceanic control. The research sheds light on seemingly contradictory glacier behaviour, e.g. we now know why neighbouring glaciers can experience very different behaviour and why glaciers such as Store have can switch from one dominant control to another.

Cook, S., Christoffersen, P., & Todd, J. (2021). A fully-coupled 3D model of a large Greenlandic outlet glacier with evolving subglacial hydrology, frontal plume melting and calving. Journal of Glaciology, 1-17. doi:10.1017/jog.2021.109