【摘 要】
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Reference evapotranspiration (ETo) and pan evaporation (Epan) are key parameters in hydrological and meteorological studies.Our objectives were to evaluate
【机 构】
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Northwest A&F University
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Reference evapotranspiration (ETo) and pan evaporation (Epan) are key parameters in hydrological and meteorological studies.Our objectives were to evaluate the ratios of ETo to Epan (kp) at daily and monthly scales, and to predict average ETo in the following years using calibrated kp and observed Epan at the 2 time-scales.Using 50 years of data obtained at 6 typical sites in north China, daily and monthly ETo was calculated using the FAO-56 Penman-Monteith equation, and kp values were determined at the 2 time scales.Values of kp varied from 0.457 to 0.589 daily and from 0.392 to 0.528 monthly for the 6 sites.Both daily and monthly kp could be fitted as multi-linear functions of longitude, latitude, elevation and relative humidity (see Eqs.12 and 13).
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