Using Earth’s Moon as a Testbed for Quantifying the Effect of the Terrestrial Atmosphere ()
ABSTRACT
In the past, t
he planetary radiation balance
served to quantify the atmospheric greenhouse effect by the difference between the globally averaged near-surface
temperature of 
and the respective effective radiation temperature of the Earth without
atmosphere of 
resulting in 
. Since such a “thought experiment” prohibits any rigorous assessment of
its results, this study considered the Moon as a testbed for the Earth in the
absence of its atmosphere. Since the angular velocity of Moon’s rotation is
27.4 times slower than that of the Earth, the forcing method, the force-restore
method, and a multilayer-force-restore method, used in climate modeling during
the past four decades, were alternatively applied to address the influence of
the angular velocity in determining the Moon’s globally averaged skin (or slab)
temperature, 
. The multilayer-force-restore method always provides the highest values for 
, followed by the force-restore method and the forcing method, but the
differences are marginal. Assuming a solar albedo of 
, a relative emissivity 
, and a solar constant of 
and applying the
multilayer-force-restore method yielded 
and 
for the Moon. Using the same values for α, ε, and S, but assuming the Earth’s
angular velocity for the Moon yielded 
and 
quantifying the effect of the terrestrial atmosphere by 
. A sensitivity study for a
solar albedo of 
commonly assumed for the Earth in the absence of its atmosphere
yielded 
, 
, and 
. This means that the atmospheric effect would be more than twice as
large as the aforementioned difference of 33 K. To generalize the findings,
twelve synodic months (i.e., 354 Earth days) and 365 Earth days,
where 
, a Sun-zenith-distance dependent solar albedo, and the variation of the
solar radiation in dependence of the actual orbit position and the tilt angle
of the corresponding rotation axis to the ecliptic were considered. The case of
Moon’s true angular velocity yielded 
and 
. Whereas Earth’s 27.4 times higher angular velocity yielded 
, 
and 
. In both cases, the
effective radiation temperature is 
, because the computed global albedo is 
. Thus, the effective radiation temperature yields flawed results when
used for quantifying the atmospheric greenhouse effect.
Share and Cite:
Kramm, G. , Dlugi, R. and Mölders, N. (2017) Using Earth’s Moon as a Testbed for Quantifying the Effect of the Terrestrial Atmosphere.
Natural Science,
9, 251-288. doi:
10.4236/ns.2017.98026.