Abstract
Records of daily total of solar radiation measured on a horizontal surface for consecutive three to seven years are available for about forty stations in Japan. Using these data, yearly and seasonal mean isopleths of solar radiation are drawn.
In the results the following features are to be pointed out:
1) The distributions are affected by the meteorological fa c tors rather than by latitude.2) The amount of solar radiation is larger in the inland district than near the sea.3) The minima of solar radiation in the Tokyo and Osaka districts are remarkable.4) The seasonal variation of the amount of solar radiation is largest in summer and then in spring, autumn and winter in the order of magnitude.5) The annual variations of solar radiation are mainly brought about by the conditions in summer.
