Abstract
To reproduce real continuous records of river discharge from discrete discharge measurements, how long should we choose time interval for discrete discharge measurement?This time interval represents the time for describing a hydrological response and it can be considered as a time scale of a hydrological response. In this study, to find out a time scale of a hydrological response and a relationship between the time scale and the catchment scale (catchment area), we analyze river discharge time series data in the Yodo River basin using the Fourier transform method and the sampling theorem. As a result, between a time scale Δt (hour) and a catchment scale A (km2), a relationship, Δt=pexp (q√A) is obtained, where p=0.6 and q=0.026.This relationship shows that Δt for a basin with 300 km2 area is about 1 hour.
