Regional Variability of Mean Annual Water Balance for Non-humid Catchments in Northern China Based on the Budyko Hypothesis

摘要

Based on long-term mean of climate and discharge in 108 non-humid catchments in Northern China, this study analyzed the regional variability of mean annual water balance based on the Budyko hypothesis. Besides the annual climate conditions, the regional pattern of water-energy balance is also correlated to the relative infiltration capacity (K_s/i_r), relative soil water storage (S_(max)/E_0), and the average slope (tanβ). This study proposed an empirical formula to enable one to estimate the parameter ω in Fu's equation (1981) from catchment characteristics without calibration from the long-term water balance. It has been shown that Fu's equation together with the parameter at estimated by this empirical formula can predict accurately the mean annual evapotranspiration.