EFFECT OF TEMPORAL RESOLUTION OF HYDROLOGICAL DATA ON CANOPY EVAPORATION DERIVED FROM AN INTERCEPTION MODEL CONSIDERING FRACTIONAL VEGETATION COVER

Abstract

The objective of this study is to investigate the effect of temporal resolution of hydrological data on canopy evaporation derived from an interception model taking into account of fractional vegetation cover. This newly developed model makes it possible to avoid a problem in our previous model which is based on the Rutter model. Hydrological data with different temporal resolution generated from a 28-year hourly hydrological data set is applied to this interception model. The effect is very significant and is quantified by a formula which relates the annual canopy evaporation with annual effective potential evaporation, canopy capacity and temporal resolution. Using this formula, true annual canopy evaporation invariant to temporal resolution can be derived from annual effective potential evaporation, canopy capacity and fractional vegetation cover. The concept of operational parameter value and its calculation algorithm are proposed. The operational parameter values corresponding to their true values and the temporal resolutions are computed to reproduce the true annual canopy evaporation. This implies the necessity to use operational parameter(s) according to temporal resolution of the data in the operation of hydrological models.