simulation shown in Figure 36, Object-GAWSER predicts 78.66 mm of total runoff while GAWSER
predicts 78.13 mm of total runoff (0.6% difference).
Results from GROFF2
The following figures show the differences and similarities between outputs from the GROFF
sector in Object-GAWSER and equivalent outputs from the Fortran version of GAWSER. To sim-
plify the discussion, the results from GROFF2 rather than all of those from GROFF1GROFF5 will
be described.
Figure 37 shows the differences and similarities between F and GAWSER_F. F begins slightly
later and peaks slightly higher than GAWSER_F. The two peaks are actually closer using the value
of IMCa instead of 0.00001 (the value used within the Fortran GAWSER, see Figure 38) for the
initial condition of TINF. Furthermore, F is slightly smaller and ends slightly later than
GAWSER_F. The difference in the beginning and ending times and magnitudes of F and
GAWSER_F is either due to computational differences between Object-GAWSER and the Fortran
version of GAWSER or a lag in Object-GAWSER that occurs as liquid water travels through STOR
before entering F (see Fig. 18).
Figure 38 shows the behavior of F using 0.00001 as an initial condition for TINF. The peaks of F
and GAWSER F are further apart than the corresponding curves shown in Figure 36.
Figure 39 shows the differences and similarities between SA_I and GAWSER_SAI. SA_I and
GAWSER SA_I are identical until just before 45 hours when GAWSER SA_I drops below SA_I
until the end of the simulation period. The difference between SA_I and GAWSER_SA_I is due to
the difference between F and GAWSER_F shown in Figure 38. SA_I is greater than
GAWSER_SA_I because Object-GAWSER simulates less infiltration into the top soil layer, thereby
rendering more available storage in the top layer.
Figure 40 shows the similarities and differences between SURF2 and GAWSER_SURF2. The
two curves exhibit the same pattern, but SURF2 is slightly larger in magnitude. The difference in
magnitude between SURF2 and GAWSER_SURF2 is due to the difference in magnitude between F
30
20
SA I
10
GAWSER SA I
0
10
20
30
40
50
60
70
80
90
Time (h)
Figure 39. Behavior of available storage in the top layer of soil (TP_LYR).
SA_I and GAWSER SA_I match identically until 43 hours. After 43 hours, SA_I
is slightly larger than GAWSER_SA_I. The difference in magnitude between
SA_I and GAWSER_SA_I is due to the difference between F and GAWSER_F
(see Fig. 37). F decrements SA_I and GAWSER_F decrements GAWSER_SA_I.
F is less than GAWSER_F for the majority of the simulation after after 43
hours; therefore, SA_I should be greater than GAWSER_SA_I after 43 hours.
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