Short-term velocity and water-pressure variations down-glacier from a riegel, Storglaciären, Sweden

摘要: During the 1991-94 summer field seasons, time-correlated measurements of water pressure and surface speed were made over down-glacier from a major riegel on Storglaciaren, Sweden. Measurements at sub-hourly time-scales in order to discern details diurnal cycle. Large water-input events, typically associated with rain storms, produced coherent, lagged surface-velocity responses that could be understood terms till deformation or decoupling, these have been discussed elsewhere. The consequences smaller water-pressure events more enigmatic, acceleration ice flow generally preceded onset local rise. From consideration data other work done hydrology we infer this area is pushed behind via relaxation extensional strain across riegel. Hence, accelerations occur response increases up-glacier precede rises. In addition, following period large storm speeds became spatially coherent phase ater-pressure This suggests lead homogeneous subglacial drainage system. Sliding laws need take into accoun such temporal changes spatial coherence