横断山区参考作物蒸散量时空变化分析

Temporal and Spatial Variation Characteristics of Reference Crop Evapotranspiration in the Hengduan Mountains

参考作物蒸散量是表征气候干旱程度以及水资源供需平衡的重要指标。本研究利用横断山区31个气象站1960—2013年逐月气象资料,采用联合国粮农组织推荐的彭曼公式计算研究区各站点逐月参考作物蒸散量,建立31个站点蒸散量序列,利用气候倾向率、累积距平法、多元逐步回归分析以及基于GIS中的反距离插值技术等方法,分析横断山区蒸散量的空间分布及时间变化趋势。结果表明:横断山区参考作物蒸散量由南向北递减。受气温上升、日照时数减少、风速及相对湿度降低的影响,研究区蒸散量变化呈上升趋势。1960—1968年研究区参考作物蒸散量逐步降低,1968—1984年研究区参考作物蒸散量逐步增加,1984—2004年研究区参考作物蒸散量逐步降低,2004—2013年研究区参考作物蒸散量逐步增加。参考作物蒸散量变化趋势区域差异性明显。就贡献率而言,研究区北部参考作物蒸散量减少与平均风速相关性大;研究区南部参考作物蒸散量增加与平均日照时数相关性大;研究区中部参考作物蒸散量增加与平均气温相关性大。

Reference evapotranspiration（ETo） is an important index for evaluating climate drought,vegetation water-consumption.Based on the meteorological data from 31 meteorological stations during1960-2013 in the Hengduan Mountainous,the reference crop evapotranspiration was calculated with the Penman formula recommended by FAO.And then,the evapotranspiration sequence of 31 stations was set up to analyze the temporal and spacial changing trend of evapotranspiration in the Hengduan Mountainous by using linear regression method,cumulative anomaly method,multiple stepwise regression analysis and inverse distance interpolation technique based on GIS.The results showed that the reference crop evapotranspiration in the Hengduan Mountainous decreased from south to north.Influenced by temperature rising and decrease of sunshine duration,wind speed and relative humidity,the evapotranspiration of this area increased.The reference crop evapotranspiration gradually reduced from 1960 to 1968,gradually increased from 1968 to 1984,gradually reduced from 1984 to 2004,and gradually increased from 2004 to 2013.The spatial variation tendency of reference crop evapotranspiration was obvious.As for the contribution rate analysis,the decrease of reference crop evapotranspiration in the north research area was largely correlated with the average windspeed;the increase of reference crop evapotranspiration in the south of research area was largely correlated with average sunshine time;and the increase of reference crop evapotranspiration had great relevance with average temperature in the middle of research area.