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The physical model of SimClimat is based on physical equations. It
differs from typical educational animations in which results are pre-recorded.
All calculations are done once the simulation is launched, depending
on the parameters chosen by the user. An infinity of simulations are
possible.
However, SimClimat's physical model differs from true
climate models (detailed in section 4) to the
extent that many parameters in the equations have been adjusted so
that the simulations yield realistic results. This parameter adjustment
is necessary because the equations are very simplified. The equations
are very simplified to limit the calculation time, in order to get
simulation results in a few seconds.
The parameters have been adjusted to satisfy the following observational
constraints:
- temperatures, concentration, ice sheet latitude, sea level,
and albedo for pre-industrial, present-day and last glacial maximum
periods (Table 1);
- Extreme variations of orbital parameters induce temperature variations
of the same order of magnitude as glacial-interglacial variations
(10°C);
- Currently, water vapor and respectively contribute to 60%
and 40% of the natural greenhouse effect;
- The warming due to a doubling of is 2.2°C when
considering the effect of the water vapor but only of 1.2°C
when neglecting this feedback ([Dufresne and Bony, 2008]).
Table 1:
Table summarizing constraints for pre-industrial, present-day and
last glacial maximum time periods.
Time period |
Pre-industrial
|
Present-day
|
Last Glacial Maximum (-21 ka)
|
Temperature |
14.5°C
|
15.5°C
|
10°C
|
|
280 ppm
|
ppm
|
180 ppm
|
Sea level |
-0.2 m
|
0 m
|
-130 m
|
Ice sheet latitude |
-
|
60°
|
45°
|
Planetary albedo |
-
|
0.33
|
-
|
|
Next: 2.2 Temporal integration
Up: 2 The physical model
Previous: 2 The physical model
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Camille RISI
2023-07-24