机构地区: 中国农业大学资源与环境学院
出 处: 《生态学报》 2010年第4期923-932,共10页
摘 要: 参考作物蒸散量是估算作物需水量的关键因子,对指导农田灌溉是有十分重要的现实意义。在气候变化的背景下,利用Penman-Monteith方法,计算华北平原典型站点1961 2007年逐日参考作物蒸散量,并从能量平衡和动力学角度对其分解,分析年际变化和季节变化特征;结合数理统计方法,研究影响参考作物蒸散量及其构成项变化的主次气候因子,为该区农田水分管理提供更有效的科学指导。研究结果表明:在华北平原全区温度显著上升、日照时数,相对湿度,平均风速呈显著下降的背景下,绝大部分站点参考作物蒸散量及构成项呈显著下降趋势。夏季的参考作物蒸散量和辐射项值相对最高,冬季值最低;春季的空气动力学项值相对比例最高。辐射项与空气动力学项年际间呈负相关关系,春夏两季之间呈不显著正相关趋势,秋冬两季呈不显著负相关趋势。辐射项的变化主要受日照时数、风速及温度的影响,其中风速的贡献是负效应;空气动力学项的变化主要受风速、相对湿度及平均温度的影响,相对湿度的贡献是负效应。参考作物蒸散量的变化主要受日照时数、相对湿度、温度日较差和风速的综合影响。此外,降水与其呈显著负相关关系,下降幅度略高于参考作物蒸散量的变化幅度。 Reference crop evapotranspiration(ET0) is the key factor to estimate crop water requirement and guide farming irrigation scheduling.Under the climate change background,daily reference crop evapotranspiration at typical stations across the North China Plain(NCP) during the period from 196 1 to 2007 were calculated by the Penman-Monteith approach.The seasonal and annual characteristics of ET0 were analyzed from the view of energy balance and dynamics.Using the mathematical statistics,primary and secondary climatic impact factors were studied for reference crop evapotranspiration and its constituents(ETrad and ETaero) respectively,for guiding farming water management more effective in the NCP.The results showed that the annual reference crop evapotranspiration and its constituents(ETrad and ETaero) were significantly declined,while annual mean temperature was significantly increased,annual mean sunshine hour,related humidity and wind speed were significantly decreased.The highest reference crop evapotranspiration and ETrad were in summer,and lowest in winter,while the spring ETaero value was highest across the NCP.The relationship between annual ETrad and ETaero was slightly negative,while was positive in spring and summer as well as negative in autumn and winter.The main climatic factors for the change of ETrad were sunshine hour,wind speed and mean temperature,and the impact of wind speed was negative to ETrad.However,the main climatic factors for the change of ETaero were wind speed,related humidity and mean temperature,and the impact of related humidity was negative.Therefore,the change of reference crop evapotranspiration was synthetically impacted by sunshine hour,relative humidity,difference of maximum and minimum temperature and wind speed.In addition,the correlation between rainfall and reference crop evapotranspiration was significantly negative,while the decline rate of rainfall was a little more than that of reference crop evapotranspiration.