豪雨の時空間分布に関する研究 -メッシュ法による広域・毎時雨量資料の解析-

Abstract

It is desirable for a case study on time and space distribution of heavy rainfall to bedone through manifold analyses based on as wide field of view as possible.As the first step for making such a study, heavy rainfalls of the four mutually noticeablecases, which were relatively wide and long in duration, were selected, and data files for adigital computer of their hourly rainfall records at observation points that are widely distri-buted (but not so densely to analyze details quantitatively) in almost whole land of Japanfor almost whole duration of them, were composed.In order to grope for methodology of this kind of analysis and for methods of quantitativegrasp of features of rainfall distribution, analyses and/or examinations of the following itemsabout great-sphere rainfall distributions of six kinds of time scale were tried by a meshmethod for the data files: (1) Ability of trace of rainy area classified by intensity throughhourly distribution maps expressed by characters of digital computer, (2) Hourly variationsof several kinds of characteristic values about space distribution (concerning intensity, area, volume and dimensionless values composed of them), (3) Relationship between size ofrainy area classified by intensity and the maximum point rainfall, (4) Figures of decreasingintensities with distance from a point of the maximum intensity in summarized rainfalldistribution at the most powerfull period.Some interesting results were obtained through these approach, although they are almostqualitative because of insufficient density of observation points and of data only on land.