基于云模型的甘肃省参考作物蒸散量变化特征及影响因子

Research on distribution characteristics and influencing factors of reference crop evapotranspiration in Gansu Province

为了深入认识甘肃省参考作物蒸散量（ET0）的变化特征,解决该地区水资源供需矛盾,利用甘肃省29个气象测站1951~2013年的日气象资料分析甘肃地区ET0年、季的时间变化趋势.依靠处理定性概念与定量描述不确定转换的云模型,对ET0时间变化特征和影响ET0的气象因子进行了分析,同时采用通径分析方法,对影响ET0变化的气象因子进行了探讨.结果表明：河西半干旱区、陇中半干旱区、陇东半湿润区、陇南湿润区4个分区ET0在近63a均表现为持续性的上下波动.ET0在时间尺度上分布较为均匀、稳定.季节分布呈现出夏季〉春季〉秋季〉冬季的分布态势.离散性方面秋、冬季最均匀,夏季最不均匀;稳定性则是冬、春季好于夏〉、秋季.年际变化来看,平均气温对ET0的直接作用最大,平均相对湿度和日照时数对ET0的间接作用最大.不同季节气象因子分析表明,春、秋、冬3个季节对ET0直接作用最强的气象因子为平均气温,夏季对ET0直接作用最强的气象因子为平均相对湿度;间接作用显示,春、秋季对ET0间接作用最强的气象因子为平均相对湿度,夏、冬季则分别为日照时数和平均气温.

In order to analyze the characteristics of reference crop evapotranspiration in Gansu Province and solve the contradiction between supply and demand of water resources in this region,the daily meteorological data from 29 meteorological stations in Gansu Province from 1951 to 2013were used.The change characteristics of was analyzed on the basis of cloud model of uncertain conversion between qualitative concept and quantitative description,and its factors of was discussed by the path analysis method.The results showed that the inter-annual variations of kept a rising trend from 1951 to 2013.At the same time,there was significant difference on the distribution of ET0 among seasons,the maximum difference was in summer,followed by in spring,and the least was in autumn and winter.The further analysis found that both homogeneity and stability of temporal-spatial distribution of ET0 had no consistency among seasons.Thehomogeneity of ET0 in autumn and winter was higher than that in spring and summer,but the stability in summer and autumn were better than that in spring and winter.The mean temperature and relative humidity had the largest direct effect on the,but the mean relative humidity and sunshine duration had the largest indirect effect on the.By the indirect effect of meteorological factors were known,the meteorological factors have mutual restriction and mutual influence,so the change of was a result of comprehensive effect of the meteorological factors.The relative humidity had the largest direct effect on the in summer and in other season it is mean temperature.The mean relative humidity had the largest indirect effect on the in spring and autumn,but mean temperature and sunshine duration had the largest indirect effect on the in summer and winter.Research result would be helpful to study on temporal-spatial variation law and estimation and prediction of evapotranspiration.