UNCERTAINTY OF CALIBRATED MODEL PARAMETER DUE TO TEMPORAL RESOLUTION OF HYDROLOGICAL DATA AND ITS REMOVAL

摘要

The objective of this study is to evaluate the effects of temporal resolution of hydrological data on a rainfall runoff analysis. When the time interval of hydrological data, the temporal resolution, is longer than the time scale of the rainfall-runoff system, for example runoff concentration time, the calibrated model parameters may be different from their "true values" and include uncertainty caused by the poor temporal resolution. In order to investigate this uncertainty, rainfall data with temporal resolution about one minute are generated by means of a random cascade model, transformed into discharge data by using a storage-function model with known parameters. Then these data are re-sampled with different temporal resolutions and used to calibrate the parameter of the storage-function model. It is shown that the temporal resolution has significant effects on the calibrated parameter, and the calibrated parameter can be expressed by its true value and the temporal resolution. By using this relationship, the effects due to temporal resolution can be eliminated, and the true value parameter invariant with temporal resolution can be derived. Furthermore, the effects of the rainfall intensity on this relationship are also discussed.