Abstract
1) How much the cooling by rain influences on the heat-budget at the ground surface is studied comparing with other terms of heat-budget equation. And then the heat-budget during rainfall is compared with those during other weather conditions.
As the result, it is made clear that during rainfall the latent heat is larger and the sensible heat is smaller. “Cooling” by rain is only a few to ten or so percentages of the net radiation but forty to fifty percentages of the heat-exchange into soil.
2) From the climatological view-point, the regional and seasonal variations are examined by considering the relation of precipitation to air temperature, which is found to be proportional to the temperature difference between surface and wet bulb (rain water). It seems that “cooling effect” is larger at the season or in the region of hot and rainy climate.
The author wishes to express his sincere thanks to Dr. E. Fukui, Honorary Professor of Tôkyô Kyôiku University for his constant guidance and encouragement for the completion of this paper. And the author wishes to dedicate this paper to Dr. Fukui in commemoration of his retirement from Tokyo Kyoiku University.
