黄河上游重要水源补给区参考作物蒸散量变化特征分析

利用甘南牧区4个气象观测站1971-2010年的地面气象观测资料,运用Penman-Monteith公式计算得出牧区四站逐月ET0值.通过统计分析、相关分析、小波及Mann-Kendall法等方法对甘南牧区ET0的变化特征进行了分析,并就高原上气象因子与ET0的相关性做了进一步研究.结果发现甘南牧区各县ET0年际变化呈逐年上升趋势,上升趋势达8.8～ 19.5mm/10a;1985年以前有明显的准10 a周期,2000年到2010年间出现了准5 a周期;在90年代以后的20年中上升更快,并于1996年以后出现了突增.牧区ET0夏季最大,并且逐年上升最快;冬季最小,逐年上升最慢.牧区ET0的空间分布不均匀除了与当地高原特殊地形地貌复杂性有关外,还与影响参考作物蒸散量的主要气象因子的不同有关.

Analysis of variation characteristics of reference crop evapotranspiration inimportant water source supply areas of the Yellow River

Because of natural and human factors, in recent years the grassland ecology of the upper reaches of the Yellow River was badly damaged by grassland degradation, desertification, and even some places the phenomenon such as water resources exhausted. Reference crop evapo-transpiration amount (ET₀) changes and have great influence on the water resources and ecological status, so the pastoral areas of Gannan ET₀ change characteristics are analyzed, and fur-ther research is carried out on whether the effeet of plateau meteorological factors is significant on ET₀ of the pastoral ar-eas. The meteorological data from 4 observatory stations in Gannan pastoral areas in 1971-2010 years are used to calcu-late ET₀ value of pastoral area from month to month with Penman-Monteith formula. Through statistical analysis, correla-tion analysis, small affected Mann-Kendall method, it is found that interannual variability of ET₀in Gannan pastoral ar-eas increases year by year, rising to 8.8~19.5 mm/10a; it shows a obvious 10-year cycle before 1985 while a 5-year cycle from 2000-2010; and it appears a faster rise in the recent 20 years since the 1990s, and even a sudden increase after 1996. The ET₀ of pastoral areas in summer is the largest and rises fastest year after year; while it in winter is the minimum and rises slowest yearby year. The uneven spatial distribution of ET₀ in pastoral areas is related not only to the complexity of local special plateau topography, but also to the difference of main meteorological factors influencing the amount of evapo-transpiration.