Sensitivity analysis is important in understanding the impact of climatic variables change on the variation of the reference evapotranspiration. In this research, mean daily reference evapotranspirations ET0 during growing season in 1988-2007 in Ejina oasis are calculated based on FAO56 Penman Monteith model and climatic data, and the sensitivity coefficients of ET0 to major climatic variables, including air temperature, wind speed, relative humidity and shortwave radiation are calculated too. Results show that the sensitivity coefficients of ET0 to the major climatic variables in Ejina oasis fluctuate significantly during growing season, and the sensitivity of ET0 to shortwave radiation is the most obvious, followed by air temperature, wind speed and relative humidity. According to this study, the response of ET0 variation to variation of air temperature, wind speed, relative humidity and shortwave radiation can be predicted with high reliability by sensitivity coefficients.
Introduction
