黄河源区陆面蒸散量的时空分布特征研究

Study on the Spatial-temporal Distribution Pattern of Land Surface Evapotranspiration over the Source Region of the Yellow River

基于修正的Penman-Monteith(P-M)模型,利用1980~2020年黄河源区的气象台站观测数据和陆-气间水热交换观测试验数据,计算出该区域的陆面参考蒸散量,分析了黄河源区蒸散量的时空演变特征,探讨了影响黄河源区蒸散量变化的原因。结果表明:(1)修正的P-M模型能较准确地估算黄河源区的参考蒸散量,与实际观测的相关系数在0.85以上。(2)黄河源区的蒸散量总体呈上升趋势,但在20世纪80年代中期和90年代中期均呈显著减少趋势;近年来,中部和西部地区的蒸散量呈减少趋势,而东部地区的蒸散量呈增加趋势。(3)黄河源区年蒸散量呈自东向西减小的分布特征,东、中、西部地区分别为473.5~516.0mm、437.6~473.5mm和386.3~437.6mm;四季蒸散量差异明显,夏季最大,春季和秋季次之,冬季最小。(4)黄河源区蒸散量随温度、风速和日照时数的增加而增大,随相对湿度和降水量的增大而减小。

Based on the modified Penman-Monteith(P-M)model,the land surface reference evapotranspiration in the source area of the Yellow River from 1980 to 2020 was calculated by using the meteorological station observation data and the land-atmosphere water-heat exchange observation data.The temporal and spatial evolution characteristics of evapotranspiration in the source area of the Yellow River were analyzed,and the reasons affecting the change of evapotranspiration in the source area of the Yellow River were discussed.The results show:(1)The modified P-M model can accurately estimate the reference evapotranspiration in the Source Region of the Yellow River,and the correlation coefficient with the actual observation is above 0.85.(2)The evapotranspiration of the Source Region of the Yel-low River shows an increasing trend,but it shows a significantly decreasing trend in the mid-1980s and mid-1990s.In recent years,the evapotranspiration in the central and western regions shows a decreasing trend,while the evapotranspiration in the eastern region shows an increasing trend.(3)The annual evapotranspiration of the Source Region of the Yellow River shows a decreasing trend from east to west,,with 473.5~516.0mm,437.6~473.5mm and 386.3~437.6mm in the east,central and western regions,respectively.Evapotranspiration was significantly different in four seasons,with the largest in summer,followed by spring and autumn,and the smallest in winter.(4)The evapotranspiration increases with the increase of temperature,wind speed and sunshine hours,and decreases with relative humidity and precipitation.