基于涡度相关仪的蒸散量时间尺度扩展方法比较分析  

Investigation on performance of evapotranspiration temporal upscaling methods based on eddy covariance measurements

作　　者：刘国水[1,2] 刘钰[1,2] 许迪[1,2] 

机构地区：[1]国家节水灌溉北京工程技术研究中心,北京100048 [2]中国水利水电科学研究院水利研究所,北京100048

出　　处：《农业工程学报》2011年第6期7-12,共6页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家973计划项目课题(2006CB403405);中国水利水电科学院博士生学位论文创新研究资助课题

摘　　要：蒸散量(ET,evapotranspiration)的时间尺度扩展是遥感反演区域ET的关键。为比较基于蒸发比、作物系数和冠层阻力的3种ET时间尺度扩展方法的估值效果,该文利用涡度相关仪实测的北京大兴区冬小麦3-6月份生育期内的ET数据,分析了蒸发比、作物系数和冠层阻力3种参数在日内的变异性并最终比较基于3种参数的ET时间尺度扩展方法的估值效果。结果表明,作物系数在日内变异性最小且其在3个时段的小时值最接近日均值,此外,对比3种方法的估值效果发现,基于作物系数的ET时间尺度扩展方法在3个时段表现效果均最优。对与具有相近气象、气候、下垫面条件和空间尺度数据的地区,推荐采用基于作物系数的时间尺度扩展方法开展从小时到日的ET时间尺度扩展。Evapotranspiration （ET） temporal upscaling method plays an essential role in ET remote sensing.In order to compare the performance of evaporative fraction method,crop coefficient method and canopy resistance method to upscale daily ET from daytime measurements,the daytime variation of evaporative fraction,crop coefficient and canopy resistance were investigated and the performance of three methods were assessed.The field work was carried out in Daxing district under winter wheat surface from March to June and the ET data was measured by eddy covariance.The results showed that the crop coefficient was more constant during daytime than evaporative fraction and canopy resistance,and the closeness of daily value and hourly value for crop coefficient was better than other two parameters.Meanwhile,the crop coefficient method performed better to upscale daily ET than other two methods.It is recommended to choose crop coefficient method to upscale daily ET data for the areas with similar climate,underlying surface conditions and data with similar spatial scale in Daxing district.

关 键 词：蒸散量 蒸发 遥感 蒸发比 作物系数 冠层阻力 时间尺度 

分 类 号：S161.4[农业科学—农业气象学]