Abstract
When we discuss about the rainfall related to occurrence of sediment-related disaster, it is important to understand the amount of rainfall as accurate as possible. However, it has not yet defined clearly about the effective area of rain gauge in case there is no rain gauge near the point sediment-related disaster occurred, and about the distance from the certain ground-based rain gauge by which estimation of risk of disaster is possible in case its rainfall exceeds the standard level. Some reports say about the spatial density distribution of rain gauges required for understanding the accurate rainfall near the area disaster occurred. But rain gauges are not placed spatially uniformly, so the correlations of each rain gauge depend on the spatial density distribution of them. Furthermore, it is very difficult to know the deviation between estimated value and true value by using current rain gauge network. In this paper, we examine the effective area of ground-based rain gauge around Hakone area in Kanagawa prefecture by using radar-AMeDAS data which are spatially uniform.
