Long-term changes in the spatial concentration of daily precipitation in Japan

Abstract

Daily precipitation data for 105 years (1901-2005) at 51 stations in Japan were analyzed to evaluate the trends in the spatial concentration of precipitation distribution. The index of spatial concentration was defined by the departure of precipitation amount from the average over the surrounding area. It is found that the degree of spatial concentration has an increasing trend, mainly for weak and moderate precipitation. A similar feature is found for precipitation over 5-31 days as well. © 2007, the Meteorological Society of Japan.