5.8 Glaciers
Last updated
Last updated
An overview of the settings in the Glaciers tab is shown in Figure 40. A distinction has been made between glacier fraction settings and the setting of glacier degree-day-factors.
5.8.1 Glacier fraction settings
In the glacier fraction settings the user has to select the following three spatial maps:
Initial glacier fraction [-]
Clean ice glacier fraction [-]
Debris covered glacier fraction [-]
These maps can be selected and added to the canvas by clicking the Select map button. The initial glacier fraction map defines for each cell the fraction that is covered by glaciers. Values for this map can range between zero and one. An example of a glacier fraction map is shown in Figure 41.
The clean ice and debris covered glacier fraction maps define for each cell the fraction covered by clean ice and debris covered glaciers, respectively. Values of these maps range between zero and one, and the sum of the fractions covered by clean ice and debris covered glaciers should always equal one.
The glacier melt runoff factor (GlacF) differentiates between the amount of glacier melt that results in direct runoff and the amount of glacier melt that percolates to the groundwater. The default value is 0.90, and values range between zero and one. The user can opt to choose a spatially distributed value for GlacF, or to choose a single value that is applied homogeneously over the entire catchment.
5.8.2 Glacier degree-day-factors
The degree-day-factors for debris covered glaciers (DDFDG) and clean ice-covered glaciers (DDFG) define the amount of glacier melt per day as a result of the average daily air temperature. Since different melting rates may apply to these two different types of glaciers, two parameters must be set here.
The user can opt to choose a single value that results in a homogeneous degree-day-factor for the entire basin, or to choose a map with a spatially distributed degree-day-factor. The maps can be selected and added to the canvas by clicking the Select map button.
After completion of all the settings in the Glacier tab you may continue with the next tab: Snow.
