甘肃省参考作物蒸散量变化特征与影响因子分析

Variation characteristics and influencing factors of evapotranspiration for reference crops in Gansu Province

为了探寻甘肃省参考作物蒸散量(ET_0)的变化特征及其影响因子,利用FAO-Penman-Monteith(98)公式计算甘肃省4个分区的ET_0。依靠处理定性概念与定量描述不确定转换的云模型对ET_0变化特征和影响ET_0的气象因子进行了研究;同时,采用通径分析的方法,对不同区域影响ET_0变化的气象因子进行了探讨。结果表明:63年来,ET_0在空间上表现为西北地区大于东南地区。其中,河西地区ET_0在甘肃省内一直处于最高值,但呈逐年减小的趋势;陇中地区和陇东地区前30年先减小,后33年较之前有所增加,但总体趋于稳定;陇南地区则表现为多年最低值且较为稳定,无明显变化。63年来河西地区ET_0分布最为离散,不均匀性也最不稳定性;陇东地区ET_0分布最为均匀,稳定性也相对最好。通径分析表明,各个气象因子对ET_0变化都有影响且对不同区域ET_0的主要影响因子也不尽相同。对河西地区和陇南地区ET_0变化直接作用最大的气象因子为平均温度;对陇中地区和陇东地区ET_0变化直接作用最大的气象因子分别为平均相对湿度和日照时数。平均风速是对河西地区、陇中地区和陇东地区间接作用最为显著的气象因子;而对陇南地区ET_0间接作用最为显著的气象因子则为日照时数。

In order to explore the characteristics and influencing factors of reference crop Evapotranspiration （ET0） and the ET0s of the 4 partition areas in Gansu Province were measured by FAO - Penman - Monteith （98） formula. The variation characteristics and meteorological factors of ET0 were analyzed based on the cloud model of uncertain conversion between qualitative concept and quantitative description. Meanwhile, the meteorological factors affecting ET0 changes in different regions were investigated by the method of path coefficient analysis. The results showed that during 1951- 2013, the ET0 in the northwest region was greater than that in the southeast. The ET0 in Hexi region was always the highest in Gansu Province, which nevertheless showed a decreasing trend yearly. The ET0s in Longzhong and Longdong regions were decreased during 1951-1980 and it became increased during 1980-2013, reaching an overall stabilized status. Longnan region was shown to possess the minimum value in years and become stable without obvious changes. During 1951-2013, the distribution of ET0 in Hexi region was most discrete, and the heterogeneity was most stable. The distribution of ET0 in Longdong region was most uniform, and stability was relatively the best. Path analysis showed that various meteorological factors had affected ET0 changes and the main influence factors in different regions were not the same. The average temperature had directly affected the changes of ET0 in Hexi region and Longxi region. The average relative humidity and sunshine hours had directly affected the changes of ET0 in Longzhong region and Longdong region, respectively. The average wind speed had indirectly affected the changes of ET0 in Hexi region, Longzhong region and Longdong region, while the sunshine hours had indirectly affected the changes of ET0 in Longnan region.