Stability of sheet flow of water beneath temperate glaciers and implications for glacier surging

摘要: A mathematical model is presented for the stability of sheet flow water beneath a temperate glacier. Enhanced viscous heat dissipation in thick parts tends to make unstable, instability increasing as thickness and pressure gradient increase. However, incipient channels may be destroyed glacier slides over protuberances on its bed. Quasi-stable possible sheets up several millimeters thickness, especially glaciers that have relatively gentle surface slopes slide at moderate high speeds. Such somewhat reduce effective roughness beds, but probably not enough allow surge initiation. Furthermore, presence numerous water-filled cavities bed will tend lessen degree “lubrication” by sheet.