Urban and Industrial Effects on Precipitation and Thunder Days in Hokkaido, Japan

Abstract

   The rainfall data, for the period 1927-1976, at nine towns in Hokkaido, Japan, have been analyzed. At Muroran, a non-urban steel-producing town, an increase of thunder days and rainfall in the warm season was found during the period 1957-1976 when an increase of steel production is reported. It seems to suggest the effects of industrial activities on weather. An increase of thunder days was also found at the non-industrial commercial city Sapporo with a population of some 1.2 million, about eight times that in 1927. However the increase is not statistically significant at the 5% level.