气候变化对河西地区参考作物蒸发蒸腾量的影响

Impact of climate change on reference crop evapotranspiration in Hexi region

【目的】探讨气候变化对参考作物蒸发蒸腾量(ET0)的影响程度,为节水农业的区域发展及水资源科学利用提供参考。【方法】根据河西地区18个气象站点的长系列气象资料月值数据,利用Penman-Monteith公式计算河西地区历年ET0值;用相关法分析各站ET0与地理位置、气象要素的关系,并应用相关法结合Penman-Monteith公式预测2010-2019年和2020-2029年ET0的年代均值。【结果】河西走廊西段、中段、东段和祁连山地的平均ET0值分别为1 265.1,1 078.6,1 058.5和984.5mm;海拔每升高100m,河西地区中部和东部各站年均ET0值约减少19mm,西部各站则约减少12.4mm;河西地区年ET0值与年平均相对湿度、年平均风速、年日照时数、年降水量、年平均气温的相关系数分别为0.634 1,0.597 3,0.421 3,0.356 6和0.191 9;预测的每10年变化量,西部的安西、玉门镇,中部高台、临泽及祁连山地的肃北站点年ET0值减少20mm以上,西部的马鬃山增加20mm以上,东部的古浪及祁连山地的天祝站点增加10mm以上,其他站点变化小于10mm。【结论】截至2009年,河西地区的年ET0值呈先减小后增大的趋势;其分布地域性比较明显,表现为河西走廊西段高于中段,中段高于东段,祁连山地最小,海拔高度是其决定因素;气象要素对于年ET0值的影响表现为年平均相对湿度>年平均风速>年日照时数>年降水量>年平均气温;未来20年河西地区东段年ET0值呈增加趋势,中段和西段多呈减少趋势,且各站差异明显。

【Objective】 The study was to investigate the influence degree of climate change on reference crop evapotransp iration（ET0）,which provides a reference for developing regional water saving agriculture and scientific utilization of water resources.【Method】 Based on long series of monthly meteorological data collected from eighteen weather stations in Hexi region,annual ET0 values were calculated with the Penman-Monteith equation.The relationships of geographical location,meteorological factors with ET0 were analyzed by correlation method.The average ET0 values of 2010-2019 and 2020-2029 were predicted with correlation method and Penman-Monteith formula.【Result】 Mean ET0 values in the west,in the middle,in the east of Hexi Corridor and in Qilian Mountains were 1 265.1,1 078.6,1 058.5 and 984.5 mm respectively.Annual mean ET0 values of the stations in the middle and in the east of Hexi region decreased by 19 mm while they decreased by 12.4 mm in the west when altitudes increased by 100 m.Correlation coefficients between humidity,wind speed,sunlight hours,precipitation,mean temperature and annual ET0 values in Hexi region were 0.634 1,0.597 3,0.421 3,0.356 6 and 0.191 9 respectively.ET0 values of Anxi,Yumenzhen in the west,Gaotai,Linze in the middle and Subei in Qilian mountains decreased more than 20 mm every ten years while ET0 values of Mazongshan in the west increased more than 20 mm.ET0 values of Gulang in the east and Tianzhu in Qilian mountains increased more than 10 mm.Changes of other stations＇ ET0 values were less than 10 mm.【Conclusion】 Up to 2009,ET0 values first decreased,and then increased in Hexi region,showing that ET0 values are related to geographical location.ET0 values of central Hexi Corridor were smaller than those in the west,but larger than those in the east.ET0 values of Qilian mountains were the least.For this altitude is the key factor.The influence capacity of meteorological factors on ET0 is as follows：humiditywind speedsunlight hoursprecipitationtemperature.In the next 20 years,most stations＇ annual ET0 values will increase in the east of Hexi region,and decrease in the middle and in the west.