Long-term Observations of Glacier Area, Snowline Elevation, and Ice Surface Elevation at Alexandra Fiord, NU (1959-2019)

Glacier outlines were digitized from historical air photos (1959) and Landsat L1TP or Sentinel-2 L1C satellite imagery. Outlines for 1959-1982 were manually traced, and for 2001-2019 were automatically delineated using the normalized difference snow index (Hall and others, 1995) with manual correction where necessary. Snowlines are drawn as single contours from the 2012 Arctic DEM at the mean annual elevations determined by three independent digitizers. The elevation change raster presents annual rates of surface elevation change (m/yr) at 41m resolution over the period 2001-2018, and derive from a time series analysis of ASTER Level 1A stereo imagery and WorldView DEMs.