Collaborative
Group Activity - Comparative Analysis of Planetary Greenhouse
Effects
Venus, Earth and Mars,
courtesy of NASA Lunar and Planetary Institute.
The calculator
below uses a simple zero-dimensional global energy balance model to compute the
mean global surface temperature. By changing values of parameters which are
input to the model, the mean global surface temperature is changed.
Greenhouse effect
parameter - is the fractional
part of the longwave radiation from the surface that is re-radiated back to the
surface. A greenhouse effect of .40 means that 40% of the longwave radiation
emitted by the earth is re-radiated back to the earth (or 60% leaves the
earth/atmosphere system). This parameter can be entered with 0, 1,
2, or 3 decimal places and has an allowable range of 0 to .999.
Incoming solar
radiation - incident at the top
of the atmosphere is entered with no decimal places and has an allowable range
of 1 to 3000 W/m2.
Albedo -
can be entered with 1, 2, or 3 decimal places and has an allowable range of .01
to .90.
The "Recalculate" button will recalculate the surface
temperature for new values in the other fields.
The "Return to initial values"
button will return all 4
fields to their initial (i.e. current) values for the earth-atmosphere-sun
system.
The original version of this
calculator can be found at Frank T. Keimig's "Climatology" course web page,
(http://www.geo.umass.edu/courses/climat/radbal.html ).