Abstract
Recently, heavy hourly precipitation has been observed in Japan. It seems that intensification of heavy precipitation is related to urbanization, heat island phenomenon and global warming. But to clarify the change of hyetograph patterns, it is necessary to take a statistical test about time series of temporal and spatial distribution. In this paper, trend analysis of temporal distribution of hourly precipitation is carried out by Mann-Kendall test. The temporal concentration degree of precipitation is quantified by a gradient of ID (Intensity-Duration) curve. By applying to the hourly precipitation dataset form 1890 to 2012 at Tokyo and 1891 to 2012 at Osaka, it was showed that the temporal concentration degree is increased in August at Tokyo. Furthermore, it was proved that the long term data is useful for trend analysis of temporal distribution of precipitation.
