Estimating Potential Evaporation in Lhasa River Basin: Improved Dalton Model

Abstract

Potential evaporation is characterized by significant inhomogeneity over regions with high mountains and deep valleys. It is usually difficult to map sparse potential evaporation data over such regions for hydrological modeling and water resources management. This paper presented an analysis of potential evaporation estimation model for such a region, the Lhasa River basin in Tibet, China. The correlation of potential evaporation with the monitored meteorological factors including the water vapor pressure difference, air water temperature difference, air temperature, and wind speed, was analyzed. The applicability of the Dalton model corrected with air water temperature difference and believed to be universal for use in China was examined. An improved Dalton model that is corrected with both air water temperature difference and air temperature was then proposed. Residual error analysis proved its adequacy and verification against the monitored data showed its applicability. The improved model would be useful for mapping potential evaporation data over the Lhasa River basin.