Ice Flow Velocity Mapping for Long-Time Motion Analysis of Typical Glaciers in Northwestern Greenland

Abstract

Current research on the Greenland Ice Sheet (GrIS) ice flow velocity has generally focused on the post-1985 period, with pre-1985 studies mainly concentrated in the typical regions of northern and northeastern Greenland. However, the GrIS lacks historical maps of ice flow velocity and analyses of long-time motion. This paper estimated the historical ice flow velocity of four typical glaciers in northwestern Greenland using Declassified Intelligence Satellite Photography (DISP) and Landsat MSS images: Petermann Glacier, Humboldt Glacier, Tracy Glacier, and Heilprin Glacier. Based on the ice flow velocity, flow direction, and DEM change trend, the central streamline of each glacier was then mapped. In conjunction with previous research, this paper examined changes in ice flow velocity on the central streamline of Petermann Glacier from the 1960s to the 2020s and changes on Humboldt Glacier, Tracy Glacier, and Heilprin Glacier from the 1970s to the 2020s. Then, we traced the ice front of each glacier from the 1960s to the 2020s and examined its changing trend. The findings showed that the ice flow velocity of all four glaciers increased, with Petermann Glacier and Tracy Glacier showing significant increases from 2005 to 2019. Furthermore, the ice fronts of four typical glaciers all shrank after 2000, with Petermann Glacier and Tracy Glacier experiencing severe retreat and perhaps even disintegration. This paper filled a gap in the historical ice flow velocity mapping in northwestern Greenland and provided valuable information for the analysis of long-time motion in this region.