237
Modeling Snowmelt Runoff under Climate Change Scenarios
zones, even when the SNOTEL station lies outside the elevation range of a particular
zone. SRM was able to generate new S(t) curves automatically for the climate change
scenarios based on degree-days of melt as described by Martinec et al. (2005).
10.4.5  Model PaRaMeteRS
SRM has been designed so that these model parameters are based on physically
observable properties or processes so that they can be derived from measurements
or estimated by hydrological judgment based on basin characteristics, physical laws,
theoretical relations, or empirical regression relations. The model parameters are
shown in Equation 10.1 and defined thereafter. The parameters are not calibrated or
optimized from historical data, and when occasional adjustments are made to the
data after they have been determined for the basin, such changes should always fall
within the range of physically and hydrologically acceptable values. Martinec et al.
(2005) provided an extensive discussion with regard to how to determine the parameter values for a particular basin.
1
0.8
0.6
0.4
Snow cover fraction
0.2
0
2 / 1
3 / 3
4 / 2
5 / 2
6 / 1
7 / 1
7 / 3 1
8 / 3 0
1989
SNOTEL 1989
CDC
FIGURE 10.11  Same as Figure 10.8, but for 1989, when MODIS data were not yet available.
1
0.8
0.6
0.4
Snow cover fraction
0.2
0
2 / 1
3 / 3
4 / 2
5 / 2
6 / 1
7 / 1
7 / 3 1
8 / 3 0
1995
SNOTEL 1995
CDC
FIGURE 10.12  Same as Figure 10.8, but for 1995, when MODIS data were not yet available.