黄河流域潜在蒸散量时空格局变化分析

Study on Spatiotemporal Change of Evapotranspiration in the Yellow River Basin

根据国家气象局整编的1957-2001年黄河流域93个气象站点的气象资料,应用1998年FAO最新推荐的Penman-Monte ith法计算潜在蒸散量,在此基础上使用克里格（Kriging）插值法生成黄河流域潜在蒸散量的分布图。结果显示：黄河流域多年平均潜在蒸散量空间分布格局受气候、地形地貌等多种因素的影响,具有明显的地域性差异。潜在蒸散量总的特点是东高西低,北高南低,由东北向西南逐渐递减;从时间尺度上看,自1957年以来,潜在蒸散量总体上呈＂下降-稳定-上升＂趋势,在20世纪90年代末增到最高;季节变化为夏季〉春季〉秋季〉冬季;具体到各月的变化趋势,黄河流域上、中、下游潜在蒸散均以5-7月份最多,11月至翌年2月最低,且不同区域之间存在着明显的差别。

In this study, the values of evapotranspiration potential in the Yellow River Basin are calculated using the Penman-Monteith method recommended by the FAO in 1990 based on the meteorological data observed by 93 meteorological stations during the period from 1957 to 2001 and authorized by China Meteorological Administration, on which a map of evapotranspiration potential distribution in the Yellow River Basin is charted using the Kriging interpolation method. The results show that the spatial distribution of annual evapotranspiration potential in the study area is strongly affected by many factors, such as the climatic, topographical, geomorphologic and geograph- ical factors, and the difference of annum evapotranspiration potential between the different localities is significant. Generally, the evapotranspiration potential decreases from the northeast to the southwest. Temporally, the annual evapotranspiration potential has been in a trend of ＂decrease-stabilization-increase＂ since 1957, and it was the highest at the end of 1990s. Seasonal evapotranspiration potential is in a sequence of summer 〉 spring 〉 autumn 〉 winter. Monthly evapotranspiration potential in the upper, middle and lower reaches of the Yellow River Basin is the highest during the period from May to July and lowest during the period from November to next February, and the difference of monthly evapotranspiration potential between the different localities is also significant.