Research of the sensitivity of the reference crop evapotranspiration to main meteorological factors in the Guanzhong region | 参考作物蒸发蒸腾量对关中地区主要气象因素变化量的敏感性分析

Chinese. 分析关中地区参考作物蒸发蒸腾量（ETref）对气象因素变化量（气象变量）的敏感性，以及敏感系数法在单气象因素变化和多气象因素变化下估算ETref的能力（预测能力）。依据关中地区31个气象站41年的气象观测资料，利用敏感系数法计算并分析关中不同地区多年日平均和月平均ETref对气象变量的敏感性；探讨不同时期对关中地区参考作物蒸发蒸腾量最具影响的气象因素；同时利用实际的数据检验多气象因素同时变化时联合公式估算ETref的精确度。关中地区ETref对气象变量的敏感性随时间和地区变化。总的来说,相对湿度为关中地区ETref最敏感的气象因素；其次是太阳短波辐射和平均气温,其敏感性相近，在5~8月份对ETref影响最强，在12到次年2月份最弱；风速总的来说是对ETref影响最弱的因素。敏感系数在单个或多个气象因素变化情况下均有较强的预测能力。

English. The research analyzed the sensitivity of the reference evapotranspiration (ETref) to climatic variables in Guanzhong region, and the power of sensitivity coefficients method reckoning the ETref response to a perturbation of one or more climatics (predictive power). Using the sensitivity coefficient method, based on the meteorological data of more than 31 weather stations about 41 years, the sensitivity of the average monthly and yearly ETref to climatic variables in different areas in Guanzhong region was studied in order to find the sensitivity coefficients which impacted ETref mainly in different periods and to test the accuracy of the co-formula used in the Guanzhong region by the actual data as well. The sensitivity of ETref to climatic variables in the Guanzhong region varied from region and time. All in all, relative humidity was the most sensitive factor in Guanzhong region, followed by net shortwave radiation and air temperature, which had similar sensitivities and most impact to ETref from May to Aug. and least impact from Dec. to Feb.. Generally speaking, windspeed had the least impact. Sensitivity coefficients have a high predictive power under the perturbation of one or more climatic changes.