According to the CIE sky model, sky conditions can be
classified by using a sky ratio method and a sky cover
method. The latter method uses the amount of clouds in
the sky for assessment and ranges from 0.0 (no clouds) to
1.0 (full cloud cover). The Korea Meteorological Administration
(KMA) classifies sky based on cloud cover in accordance
to the sky cover method. Cloud cover is determined
by expert visual observation, and the amount of clouding is
classified from ‘0’ to ‘10.’ This study used cloud cover
ranges (from 0.0 to 1.0) based on the cloud cover range
(from 0 to 10) obtained from the KMA and classified sky
conditions with such values.