1 Spatial Modelling of the Terrestrial Environment - Georeferencial

24 Spatial Modelling of the Terrestrial Environment
North-east Greenland
Ice stream
150 km
Figure 2.6 A shaded relief plot of an InSAR-derived DEM of part of the Greenland ice sheet
covering the north-east Greenland ice stream. The coverage of the InSAR data is roughly
between the two white lines and the DEM was generated with a 500 m posting
drainage basins. Due to the size of the ice sheets, their non-linear, integrative response to
different forcing fields and their long-response time, different basins may be behaving in
entirely different ways at any one time. In southern Greenland, for example, one basin,
east of the main divide, appears to be losing mass, while to the west, the basin is gaining
mass by almost the same significant amount (Thomas et al., 2000). This was a surprising
and puzzling result, with no clear explanation. It highlights the importance of a regional
interpretation of mass balance signals. The key to this regional approach is the accurate
delineation of ice divides.
This has been undertaken for both Greenland and Antarctica using a GIS-based approach
by combining slope and aspect, derived from the DEMs (Hardy et al., 2000; Vaughan et al.,
1999). The drainage basin masks were used to estimate the area of each basin and the volume