Climatology of Extreme Precipitation in Japan for Different Time Scales

Climatological features of the distribution of extreme precipitation in Japan were documented using record values of ten-minute, hourly and daily precipitation for 1994 to 2009. It was found that the distribution of top ten-minute precipitation has a moderate north-south gradient (increasing southward at about 3% per degree in latitude), while ten-minute precipitation of lower ranks (up to 50th to 100th cases at each station) shows a stronger latitude dependence (about 6% per degree) that is comparable to those of hourly and daily precipitations. In addition, extreme precipitation shows local maxima on southern sides of land in western Japan corresponding to orographic enhancement, which is found for all the time scales but is most conspicuous for daily precipitation.