摘要

Iceberg calving is an efficient mechanism for ice mass loss, and rapidly calving glaciers are often considered to be inherently unstable. However, the Physical controls on calving are not well understood. Recent studies hypothesize that the presence of a rigid ice malange (composed of icebergs, bergy bits, and sea ice), can reduce iceberg calving by providing "backstress" to the terminus. To test this hypothesis we use remote sensing techniques to construct a time series model of calving rate and size and composition of the adjacent ice melange. We describe a semi-automated routine for expediting the digitization process and illustrate the method's for Helheim Glacier, East Greenland, using 2008 data. Ice velocities of the glacier terminus and ice melange are derived with feature-tracking software applied to radar imagery, which is successfully tracked year-round. Object-based image analysis (OBIA) is used to inventory icebergs and sea ice within the ice melange. We find that the model succesefully identifies the calving rate and ice melange response trends associated with seasonal increases in terminus retreat and advance and shows seasonal trends of ice melange potentially providing seasonal backstress on the glacier terminus.

  • 出版日期2014-10