贵州省参考作物蒸散发量的时空变化分析

Spatio-temporal Variation of Reference Evapotranspiration in Guizhou Province from 1960 to 2009

利用1960～2009年贵州省18个气象站的逐日气象资料,应用FAO Penman-Monteith方程,计算了参考作物蒸散发量(ET0),分析了贵州省参考作物蒸散发量时空变化特征以及主要影响因素。结果表明:贵州省各个地区年均ET0在634～936mm之间;从1960年到2009年,年参考作物蒸散发量总体呈下降趋势,年际变化率为-1.70mm/a;从20世纪60年代起,各年代ET0呈减小趋势;春季、夏季和冬季的ET0下降趋势显著,秋季的下降趋势不明显;对全年和各个季节的ET0影响最大的气候因素都是日照时数。贵州省显著减小的日照时数可能是ET0呈减小趋势的原因。

By using daily observed data from 18 meteorological stations of Guizhou Province from 1960 to 2009 and the FAO Penman-Monteith method,the variation trend of reference evapotranspiration（ET0） was analyzed in this study.By utilizing the method of Spline interpolation under ArcGIS,the spatial distribution of ET0 was proposed and the regional differences were compared.Moreover,multiple regression analysis was employed to analyze the dominating climatic factor affecting ET0.The results indicated that the annual ET0 of each area in Guizhou Province range from 634 mm to 936 mm.From 1960 to 2009,the annual ET0 showed a decreasing trend in general and varied at the rate of-1.70 mm/a.Since the 1960s,the ET0 has decreased from one to another decade.The ET0 in spring,summer and winter assumed remarkable downward trends,while the decreasing trend in autumn was not obvious.The sunlight hours were the dominating climatic factor influencing ET0.The decreasing sunlight hours might be the main reason leading to the decreasing of ET0.