降雨の時間配分に関する確率論的考察

Abstract

Under the present condition that a fine prediction of hyetograph is impossible, the statisticalcharacters of time distribution of a heavy rainfall will be an available basis of judgment for shortrange water problems such as flood control or flood forecasting.From mainly this point of view, this paper deals with the statistical characters of some factorson the normalized shape of hyetograph of a short term (one day or under), firstly through a mathe-matical analysis of a model of occupancy problem regarding rainfall units as balls and devided partsof rainfall time as cells under the assumption that the process of the distribution of a rainfall israndom, and secondly, with thoes of the same factors in order to verify the mathematical analysisand of the other factors, through a statistical analysis of data of actual hyetographs.The probability distributions of some factors of hyctograph are obtained by the mathematicalanalysis and it is concluded that the process of the distribution of a rainfall is nearly random butnot quite random by the data analysis.The present approach will play an important role in design of water works against floods also.