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employing the weighting function for the “visible” grid points based on the
corresponding viewing geometry. Thus constructed temperatures allow for
a direct comparison with the SWAS measurements. For simplicity, they are
referred to as “global means” in this paper.
Figure 2 compares the simulated global “visible” surface temperature
between
L
s
= 165 and 235
◦
with the SWAS and MGS-TES measurements.
Since the data from MGS-TES exist for local times 2:00 and 14:00 only, they
cannot be directly compared with the SWAS. Instead we made an assump-
tion that diurnal variations of the Martian surface temperature follow the
time dependence reproduced by the model. Thus, the corresponding plot
in this figure is actually composed of the MGS-TES data at the two local
times interpolated according to the assumed diurnal time dependence, and
followed by averaging over the visible disk in the manner similar to the one
described for the model output. Figure 2 shows an overall consistency in
the time series. The temperature drops with the onset of the dust storm in
both the measurements and simulations, although the drop is more gradual
in the observations than in the model. To emphasize the role of the dust
in the radiative energy transfer, we included the surface temperature sim-
ulated with the dust radiation scheme turned off. As seen in the figure, the
Fig. 2. Global mean surface temperature simulated with the Martian GCM and mea-
sured from SWAS and MGS-TES. The solid line represents the temperature for the run
with dust radiation included (the dust distribution is as in Fig. 1); the dashed line is
for the run without the dust. The crosses and dotted error bars show the observational
results by SWAS.
3
The diamonds present the MGS-TES observation.
