Surface velocities of a Greenland outlet glacier from high‐resolution visible satellite imagery¹

Modeling iceberg‐rafted sedimentation in high‐latitude fjord environments

“…There have been a number of studies of the dynamics of Kangerdlugssuaq Glacier and calving rates have been measured directly. Kangerdlugssuaq Glacier has been observed to have had a stable speed of about 5–6 km yr −1 , with calving rates of 13–17 km 3 yr −1 , from 1966 until 1995 [ Csathó et al , 1999; Dwyer , 1995; Reeh , 1984; Thomas et al , 2000] and the calving front has remained in approximately the same position between 1966 and 1998, probably pinned at the edge of a bathymetric slope into deeper water seaward of this location [ Thomas et al , 2000]. However, between 1993 and 1998 it underwent rapid thinning of 50 meters over the front 5 km of the glacier [ Thomas et al , 2000].…”

Satellite archives reveal abrupt changes in behavior of Helheim Glacier, southeast Greenland

“…A simple approach adapted from change-point analysis theory (e.g. Chen and Gupta, 2000) was used to locate the exact location of change-points, which are instances in time where the statistical properties before and after this time point differ. Here we tested different windows to optimally delimit the periods, based on maximizing W, the Levene's test statistic for homogeneity in variance (Levene, 1960) in adjacent periods.…”

“…Here, glacier surface velocity was extracted from imagery in selected periods of interest in the mid-1980s with large-amplitude changes in the front position. Several techniques have been developed to measure ice flow velocity (Bindschadler and Scambos, 1991; Csatho and others, 1999; Howat and others, 2007). Visual (manual) feature tracking from consecutive images has been demonstrated to provide results comparable with automated methods (Whillans and Tseng, 1995).…”