中文摘要：

蒸散发是水文循环的重要环节,分析潜在蒸散发对气候因子的敏感性有助于深入理解气候变化对水文循环的影响。本文基于Penman-Monteith公式,分析了海河流域潜在蒸散发对气温、风速、水汽压和太阳辐射的敏感性及其时空变化规律。研究结果表明：①在年尺度上潜在蒸散发对水汽压最为敏感,其次是温度和太阳辐射;在季节尺度上,春夏两季潜在蒸散发对温度最为敏感,对风速最不敏感;秋冬两季潜在蒸散发对水汽压最为敏感,对太阳辐射最不敏感;②从空间分布上看,潜在蒸散发对温度和水汽压的敏感系数以海河流域南部和冀东沿海的低海拔地区为最高,流域北部的燕山和太行山高海拔地区为最小;③潜在蒸散发对太阳辐射变化的敏感性表现出从南到北递减的趋势,对风速变化的敏感性则表现出由南往北递增的趋势;④趋势分析表明,海河流域1957～2008年间,潜在蒸散发对风速、太阳辐射和温度的敏感程度都呈增大趋势,其中对温度的敏感程度增大趋势最为明显,对水汽压的敏感程度有减弱的趋势。

英文摘要：

Evapotranspiration is a key process in hydrologic cycle. Sensitivity analysis of potential evapotranspiration （ET0） is helpful in understanding the impact of climate change on hydrologic cycle. In this paper, a non-dimensional sensitivity coefficient was employed to identify the sensitivity of ET0 to the variation of air temperature （Tmean）, solar radiation （Rs）, vapor pressure （VP） and wind speed （U2） in the Haihe River basin （HRB）. ET0 was estimated with the FAO Penman-Monteith equation. The results showed that the reference evapotranspiration was most sensitive to VP, which is followed by Tmean, Rs and U2 on an annual scale. In terms of season, Tmean was the most sensitive variable and U2 was the least sensitive variable in spring and summer, while VP was the most sensitive variable and Rs was the least sensitive variable in autumn and winter. Spatially speaking, the temperature （STmean） and vapor pressure （SVP） of ET0 sensitivity coefficients showed a decreasing trend from plain to hilly region. The coefficients of solar radiation （SRS） decreased from south to north of the HRB, while that of wind speed （SU2 ） increased from south to north. The long-term trend analysis of sensitivity coefficients for the period from 1957 to 2008 showed that , SRS and STmean increased, while SVP decreased.