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Compare the resulting temperatures with and without feedback. Try the effect of changing
the values of the various parameters to see if the results changes as you expect.
Surface Temperatures
- With Feedback is the temperature the surface would reach
with ice-albedo feedback.
- Without Feedback is the temperature the surface would reach
if there were no ice-albedo feedback.
The parameters used in the model are :
- Incoming Radiation is a number between 0 and 1 which
represents the proportion of the incoming energy which reaches the surface.
- Greenhouse Parameter is an addition to the surface temperature,
in degrees centigrade, caused by the presence of the greenhouse effect. It is normally about
33oC.
- Surface Albedo is a number between 0 and 1 which represents
the proportion of the radiation incident on the surface which is reflected back.
Bare ground normally has an albedo of about 0.25.
- Ice Albedo is a number between 0 and 1 which represents
the proportion of the radiation incident on a surface of ice or snow which is reflected back.
Ice normally has an albedo of about 0.75.
- Critical Temperature (Low) is a temperature, in oC,
below which the surface is completely ice covered.
- Critical Temperature (High) is a temperature, in oC,
above which there is no surface ice.
- Set Maximum Iterations allows you to set the number of calculations
the program will make before stopping, assuming it does not reach its accuracy criterion.
- Set Accuracy is the difference between successive calculations
of the feedback temperature below which the program will stop.
Control Readout
- Actual Iterations is the number of calculations the program
actually makes before stopping. If this is equal to the maximum iterations then the program may
not have converged and the result may be inaccurate.
- Actual Accuracy is the difference between successive calculations
of the feedback temperature at which the program has stopped. This should be less than the set accuracy
if the program has calculated successfully.
- Convergence tells you if the program has successfully calculated
the correct values.
- Ice Ground Cover is a number between 0 and 1 which tells you
what proportion of the surface is covered in ice.
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