Error of Saturation Vapor Pressure Calculated by Different Formulas and Its Effect on Calculation of Reference Evapotranspiration in High Latitude Cold Region

Teten, Buck and Magnus formulas for saturation vapor pressure es calculation were evaluated under different temperature conditions, compared with Goff-Gratch formula. Then errors of vapor pressure deficit VPD and reference crop evapotranspiration ET0 derived from es by Teten were examined in high latitude cold regions. Error of es by Teten increased linearly with reduction of temperature. When it was applied for ET0 calculation by Penman-Monteith equation in high latitude cold region, errors of VPD and ET0 were acceptable with relative error lower than 10% only when average daily temperature is above -10 °C, but error increased with the decrease of temperature. Buck and Magnus may be feasible substitute for Teten because of well performance.