2002 Volume 46 Pages 127-132
Although both temporal and spatial scales of heavy rainfall and flood disasters are different from drought's, it is same for these disasters that spatial distribution of precipitation is more useful than point precipitation that is observed at each observation point. This means that clarifying the special correlation structure of precipitation is required regardless of the scales for investigating these disasters. The authors obtained results as follows; 1) correlation coefficient of precipitation during more than one day increases when a period of accumulation increases; 2) starting point from which cumulative precipitation is calculated often affects strongly to the correlation. Moreover, results for the cumulative precipitation whose time scale is less than 24 hours are as follows; 3) the correlation weakens if a criterion of heavy rainfall increases; 4) when the duration is relatively long and the criterion is large, there is a possibility that heavy rainfall or flood disaster occur due not only to the precipitation depth itself, but also to the strong correlation.
