Geoscience Reference
In-Depth Information
Table 6. Total bias scores for extreme daily temperature
simulation for 1976-1990 validation period.
Evaluation indices
SDSM
LARS-WG
Tmax-moy
16
32
Tmax-std
31
13
Tmax90p
9
7
Tmin10p
9
7
Tmin-moy
22
25
Tmin-std
24
22
Tmean-moy
14
33
Tmean-std
33
12
DTR
8
7
Fr-Th
8
10
FSLs
0
3
GSL
1
3
Total
175
174
4. Summary and Conclusions
In this study, because of various practical advantages of SD methods over
DD procedures, two popular SD techniques based on the LARS-WG and the
SDSM models have been selected for testing their ability to simulate daily
precipitation and extreme temperature series for four raingage stations in
the Montreal region in Quebec, Canada. Calibration of the SDSM suggested
that local precipitation was mainly related to the large-scale climate vari-
ables such as the zonal velocities, meridional velocities, specific humidities,
geopotential height, and vorticity, while the local maximum and minimum
temperatures were strongly related to the geopotential heights and specific
humidities at all levels.
The comparison between some selected statistics of observed weather
data and those of weather data generated by the two models indicates
that the LARS-WG model can provide the daily precipitation statistics
more comparable to those of the observed data than the SDSM. However,
both models were unable to reproduce accurately these observed statistics.
The SDSM and LARS-WG were found to be able to describe adequately
the observed statistics of daily temperature extremes, and the SDSM was
found to be somewhat more accurate than the LARS-WG. In terms of
practical applications, calibration of the LARS-WG model is much simpler
than that of the SDSM. The calibration of the SDSM is based on a complex
procedure in order to be able to establish successfully the good relationships
