Changes in mass balance, velocity, and surface profile along a flow line on Barnes Ice Cap, 1970-1984

On a number of occasions between 1970 and 1984, measurements of mass balance, surface velocity, and surface elevation were made along a 10.2 km flow line extending from the divide to the margin on Barnes Ice Cap, Baffin Insland, Canada. Along the down-glacier half of the flow line the decrease in thickness was accompanied by an increase in slope. Within 4 km of the margin the decrease in thickness resulted in a decrease in horizontal velocity of up to c.15%, despite the increase in slope. Higher on the glacier, however, the horizontal velocity increased c.5%. These changes are broadly consistent with those estimated from the changes in shear stress calculated using the hydrostatic approximation. -from Authors