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A.d.vi. Solar flux and zenith angle
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The solar flux is integrated over all wavelengths at the top of the
atmosphere,  , becomes dependent on season, latitude and
local time. In this section, we show the formulation
of as a function of local time at a specified
season and latitude.
Assume that (W m-2)
is the solar constant at the mean orbital radius of a planet,
 and  are the radius
of its orbit and its mean value,
 is solar zenith angle,
 is latitude,
 is the solar declination angle,
 is the hour angle
( ).
Then
is represented by using the following
variables (cf. Ogura, 1999).
and are given as follows.
where ω is the true anomaly,  is the semi-major axis of orbit,  is eccentricity,  is obliquity,
 is the true anomaly of vernal equinox.
longitude of the vernal equinox relative to
the perihelion.
By introducing the areocentric longitude of the Sun
 and assuming
=
,
is rewritten as follows.
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(A.54) |
In this study,
= 0.093,
= 25.2°,
= 100°,
and
= 591 Wm-2.
The value of
is derived from Figure 1-1 of Carr (1996).
The other parameters are adapted from
Scientific Handbook (National Astronomical Observatory of Japan, 2000).
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