A two-layer model used to get the estimated values of crop transpiration by inversion using remote sensing data, which has been proved effective at some agricultural-ecological sta-tions, is first discussed. An import...A two-layer model used to get the estimated values of crop transpiration by inversion using remote sensing data, which has been proved effective at some agricultural-ecological sta-tions, is first discussed. An important part of it is the temperature separation model (in which thesurface temperature in a mixed pixel is separated into soil surface temperature and crop canopysurface temperature) on the basis of bi-temporal radiometric temperature in a mixed pixel and its thermal inertia. To improve the inversion, the authors put forward some new algorithms, including an algorithm for the estimation of regional emissivities, a static feedback algorithm using surfacetemperature for the extension of air temperature at ecological stations to the region surroundingthem and a spatial extension algorithm for calculating the wind speed 2 m above the ground withsurface roughness and radiometric temperature. Finally, regional distributions of crop transpiration (CT) and soil water use efficiency (SWUE) in North China were calculated pixel by pixel usingNOAA-AVHRR data and surface measurements and calibrations. The results provide a way toassess the effects of various agricultural practices on SWUE by using remote sensing data inNorth China in spring.展开更多
基金This work was supported by the Key Project of the National Natural Science Foundation of China(Grant No.49890330)the National Basic Research Project(Grant No.2000077900)the Research Institute of Sciences and Natural Resources,the ChineseAcademy of Sciences(Grant Nos.CXIOG-C00-05-02 and CXIOG-E01-01,04).
文摘A two-layer model used to get the estimated values of crop transpiration by inversion using remote sensing data, which has been proved effective at some agricultural-ecological sta-tions, is first discussed. An important part of it is the temperature separation model (in which thesurface temperature in a mixed pixel is separated into soil surface temperature and crop canopysurface temperature) on the basis of bi-temporal radiometric temperature in a mixed pixel and its thermal inertia. To improve the inversion, the authors put forward some new algorithms, including an algorithm for the estimation of regional emissivities, a static feedback algorithm using surfacetemperature for the extension of air temperature at ecological stations to the region surroundingthem and a spatial extension algorithm for calculating the wind speed 2 m above the ground withsurface roughness and radiometric temperature. Finally, regional distributions of crop transpiration (CT) and soil water use efficiency (SWUE) in North China were calculated pixel by pixel usingNOAA-AVHRR data and surface measurements and calibrations. The results provide a way toassess the effects of various agricultural practices on SWUE by using remote sensing data inNorth China in spring.
