Estimation of Rice Evapotranspiration Using Reflective Images of Landsat Satellite in Sefidrood Irrigation and Drainage Network  

作　　者：Maryam TAHERPARVAR Nader PIRMORADIAN 

机构地区：[1]Water Engineering Department, Faculty of Agricultural Sciences, University of Guilan

出　　处：《Rice science》2018年第2期111-116,共6页水稻科学（英文版）

摘　　要：More accurate estimation of crop evapotranspiration(ET_c)in a regional scale has always been one of the most important challenges.Temporal and spatial monitoring of ET_(c )using satellite images can help to enhance accuracy of estimations.In this study,the(ET_c)_(rice) maps were produced by using statistical/experimental methods based on crop coefficient(K_c)maps derived from vegetation index(Ⅵ).K_c was estimated using four methods,including linear relationship between K_c and Ⅵ(K_c-Ⅵ),calibrated model of K_c-Ⅵ,linear relationship between K_(cb)(the basal crop coefficient)and Ⅵ(K_(cb)-Ⅵ),and calibrated model of K_(cb)-Ⅵ.The results showed that calibrated model of K_c-Ⅵ had a better performance compared to the other methods,with normalized root mean square errors(NRMSE),mean absolute error and root mean square error being 5.7%,0.05 mm/d and 0.06mm/d,respectively.(ET_c)_(rice) maps were produced by using calibrated model of K_c-Ⅵ and reference evapotranspiration(ET_0)from FAO Penman-Monteith method.The NRMSE was 21.3%for using FAO Penman-Monteith method.Therefore,calibrated K_c-Ⅵ model in combining with ET_0 based on the Landsat 7 ETM+images could be provided a good estimation of(ET_c)_(rice) in regional scale,and can be applied to estimate water requirement due to the free and facilitate access.More accurate estimation of crop evapotranspiration(ET_c)in a regional scale has always been one of the most important challenges.Temporal and spatial monitoring of ET_(c )using satellite images can help to enhance accuracy of estimations.In this study,the(ET_c)_(rice) maps were produced by using statistical/experimental methods based on crop coefficient(K_c)maps derived from vegetation index(Ⅵ).K_c was estimated using four methods,including linear relationship between K_c and Ⅵ(K_c-Ⅵ),calibrated model of K_c-Ⅵ,linear relationship between K_(cb)(the basal crop coefficient)and Ⅵ(K_(cb)-Ⅵ),and calibrated model of K_(cb)-Ⅵ.The results showed that calibrated model of K_c-Ⅵ had a better performance compared to the other methods,with normalized root mean square errors(NRMSE),mean absolute error and root mean square error being 5.7%,0.05 mm/d and 0.06mm/d,respectively.(ET_c)_(rice) maps were produced by using calibrated model of K_c-Ⅵ and reference evapotranspiration(ET_0)from FAO Penman-Monteith method.The NRMSE was 21.3%for using FAO Penman-Monteith method.Therefore,calibrated K_c-Ⅵ model in combining with ET_0 based on the Landsat 7 ETM+images could be provided a good estimation of(ET_c)_(rice) in regional scale,and can be applied to estimate water requirement due to the free and facilitate access.

关 键 词：vegetation index LYSIMETER SATELLITE data EVAPOTRANSPIRATION CROP coefficient LANDSAT image 

分 类 号：S511[农业科学—作物学]