Dynamics and Hydrology of a Small Polythermal Valley Glacier

ABSTRACT

Storglaciären is a small valley glacier in northern Sweden. Detailed studies of surface velocity, glacier hydrology and ice dynamics between 1981 and 1995 have revealed unexpected details of dynamic behaviour of the glacier. The glacier accelerates and decelerates, frequently on a diurnal basis, in direct response to subglacial water pressure variations. Furthermore longitudinal coupling effects are evident where the glacier flows across irregularities on the bed. This coupling is caused by a change in the hydraulic system underneath the glacier as the glacier flows across a bedrock ridge. Since the properties of the drainage system can change over small distance, the dynamics of the glacier is also spatially highly variable. Thus, small glaciers, such as Storglaciären, are not as sluggish as may be expected but exhibit behaviour similar to that of larger glaciers. This means that features of large glaciers and ice sheets can be studied on smaller glaciers where logistics and experimental set-ups are easier to establish.