典型喀斯特地区参考作物蒸散量的时空变化分析——以贵州省为例

喀斯特地区地表地下的二元储水结构导致地表水渗漏严重,而土被浅薄且分布不连续,土壤蓄水量不足,易导致作物出现缺水。以贵州省为例,基于FAO-56 Penman-Monteith公式和气象资料,估算了贵州省1961~2014年参考作物蒸散量ET_O,在此基础上运用反距离权重插值法对贵州省ET_O进行空间插值,分析了贵州省ET_O的时空变化特征,并用多元回归分析方法探讨了影响贵州省ET_O的主要因素。结果表明:贵州省西部地区的ET_O高于中、东部地区;1年之中ET_O主要集中于夏季和春季,冬季最少;60年代的ET_O高于多年平均值,70年代之后逐渐降低,90年代达到最低值,2000年以来ET_O急剧升高;从年际变化看,贵州省年平均ET_O总体呈波动上升趋势,1961~2002年持续降低,2003年以后显著升高;年际变化中秋季ET_O变化最大,其次为春季、夏季,冬季变化最小;影响贵州省ET_O的主导气象因素是日照时数,两者呈显著的正相关,地理纬度与ET_O存在明显的负相关。贵州省ET_O的时空特征研究及其影响因素分析将为其他喀斯特地区的农业发展和水资源合理配置提供科学依据。

Temporal and Spatial Variation of Reference Crop Evapotranspiration in Guizhou Province, China

Water shortage problem is very serious in karst areas of the Southwestern China. Agricultural ecological environment is fragile and agricultural water is difficult to guarantee. Taking Guizhou Province as an example, based on the FAO-56 Penman-Monteith equation and meteorological data, the reference crop evapotranspiration(ET_O) from 1961 to 2014 in Guizhou Province was estimated. The reference crop evapotranspiration was interpolated in the whole province by using IDW method and temporal and spatial variation of ET_O were analyzed. Besides, the main factors influencing ET_O in Guizhou Province were analyzed by using multiple regression analysis method. Results show that ET_O in the west of Guizhou is higher than that in the eastern and middle part of the province. In a year, ET_O is higher in summer and spring than that in autumn. ET_O is the lowest in winter. ET_O in 1960s was higher than the average. After 1970s, ET_O was gradually decreasing, and reached the lowest value in 1990s. The annual ET_O has risen sharply since 2000. The annual average ET_O of Guizhou Province fluctuated in the overall upward trend. ET_O had significantly decreased from 1961 to 2002, and after 2003, it has been in the upward trend. The variation rate of ET_O in autumn is higher than that in spring and summer; the variation rate in winter is the lowest. The dominant factors of ET_O are bright sunshine hours. Besides, geographical latitude is in significantly negative correlation with ET_O. The research on spatial and temporal characteristics of ET_O in Guizhou Province and its influencing factors will provide scientific basis for agricultural development and water resources allocation in other karst areas.