SHORT-TERM VELOCITY VARIATIONS AND BASAL COUPLING NEAR A BERGSCHRUND, STORGLACIAREN, SWEDEN

Distance measurements using an automated electronic distance-measurement system in the north cirque of Storglaciaren, Sweden, during the summer of 1989, revealed a diurnal variation in glacier speed. Amplitude and timing of the diurnal cycle correlate well with the timing and intensity of the diurnal temperature cycle, indicating that speed responds to variations in daily melt with a lag of approximately 4 h. One 2 d period of non-diurnal velocity variations corresponded with a large rainfall event. Finite-clement modeling suggests that these velocity variations must be closely related to water inputs in the cirque rather than to longitudinal coupling with lower parts of the glacier.