利用20个气象站1960-2006年的逐日气象资料,应用FAO Penman-Monteith模型,分析了祁连山及河西走廊潜在蒸发量的变化趋势,并在ArcGIS环境下通过Spline插值法分析了潜在蒸发量变化的空间分异,此外运用多元回归分析法对影响潜在蒸发量变化的主导因素进行了探讨。结果表明:祁连山及河西走廊的年潜在蒸发量在20世纪80年代之前偏高,之后偏低,在1967年之前呈减小趋势,之后呈增加趋势,1974年之后又呈减小趋势,1993年之后又呈增加趋势;年潜在蒸发量的年际变化率为-1.67 mm,表明潜在蒸发量总体上呈减小趋势;从季节来看,秋季的潜在蒸发量呈增加趋势,其它季节呈减小趋势,其中春季的减小幅度最大;风速是影响潜在蒸发量变化的主导因素,影响秋季潜在蒸发量变化的主导因素是气温。
Based on the daily data from 20 meteorological stations from 1960 to 2006 and the combination of the Penman-Monteith model, the change trend in potential evaporation (PE) over Qilian mountains and Hexi corridor is analyzed in this study. With the method of Spline under ArcGIS, the spatial distribution of PE is drawn in order to research the regional difference. And the multiple regression method is used to discuss the dominant factor affecting the PE. The results indicate that the annual PE is higher before 1980s than after, and experiences the process from the decrease before 1957 to the increase since then, and to decrease after 1974 to the increase after 1993. There is a decreasing trend in general because the change rate of the annual PE varies at - 1.67 mrn. The potential evaporation increases in autumn, however, decreases in other seasons, especially in spring. The wind speed is a dominant factor influencing PE. When autumn comes, the temperature becomes the key factor influencing PE.