潜在蒸散量是确定作物需水量的重要依据和基础，准确估算和科学分析其气象影响因素，对于优化调整农业种植结构及合理配置水土资源具有重要意义。根据河北省及相邻行政区内24个气象站点1960－2016年的逐日气象数据，采用联合国粮食及农业组织（FAO）推荐的Penman Monteith公式计算潜在蒸散量（ET0），利用敏感系数和贡献率对ET0变化的气候影响因素进行分析，结果表明：近57年来河北省ET0多年平均值为1095.70mm，整体呈显著下降趋势，平均下降幅度为-8.91 mm/（10a）； ET0年内变化率夏季最高，冬季最低；ET0空间分布大致自西向东呈半环状递减趋势，四季与年尺度格局基本一致。河北省年平均ET0对相对湿度表现为负敏感，对其他气象因子表现为正敏感。ET0年变化对各气象因子的敏感程度依次为相对湿度>最高气温>平均风速>日照时数>平均气温>最低气温，其变化对气象因子的敏感性存在空间差异。平均风速是河北省ET0全年及春、秋、冬三季变化的主导因子，日照时数为夏季ET0变化的主导因子。空间分布上，西北部地区ET0变化的主导因子为平均气温，东北部地区为日照时数，中南部及沿海地区ET0变化的主导因子为平均风速。该研究成果可为水资源的优化配置及区域干旱评价提供一定的理论支撑。

The potential evapotranspiration is an important basis for determining the crop water demand.Accurate estimation and attribution its meteorological influencing factors are of great significances for optimizing the adjustment of agricultural planting structure and rational allocation of water and soil resources.The spatiotemporal variations of potential evapotranspiration and its climate influencing factors in Hebei Province were investigated based on daily weather data from 1960-2016 at 24 meteorological stations in Hebei Province and adjacent administrative regions,Penman Monteith formula sensitivity coefficient,and contribution rate.Results showed that the average ET0 in Hebei Province was 1095.70 mm in the past 57 years.It showed an overall downward trend with an average magnitude of -8.905 mm/（10a）.The ET0 change rate of was the highest in summer season and the lowest in winter season.The spatial distribution showed a general semi circular decreasing trend from west to east,and its seasonal variations were basically consistent with that of annual scale.The annual average ET0 was negatively sensitive to relative humidity and positively to other meteorological factors.The sensitivity of each meteorological factor was:relative humidity>maximum temperature>average wind speed>sunshine hours>average temperature>minimum temperature.The average wind speed was the dominant factor for the change of ET0 in the whole year and in spring,autumn and winter seasons.Sunshine hours were the dominant factor for the change of summer ET0.In terms of spatial distribution,the dominant factor of ET0 variation in the northwestern region was the average temperature,the northeastern region the sunshine hours,and the central and southern regions the average wind speed.The results can provide theoretical supports for the optimal allocation of water resources and regional drought assessment.

国家自然科学基金（51579126；51779114）；辽宁省“百千万人才工程”资助基金；大连市科技创新基金（2018J13SN116）