Abstract
The photochemical reflectance index (PRI) derived from narrow band reflectance centered at 531 and 570 nm is related to the light use efficiency (LUE) of photosynthesis by terrestrial vegetation. Thus, there is a possibility that LUE can be estimated from the remotely sensed data via PRI. However, the satellite sensor that has these two spectral bands has not existed so far. Therefore, it is necessary to substitute PRI using spectral bands of current satellite sensors. In this study, first we investigated the effectiveness of alternative indices of PRI by the band combination and the multiple regression analyses that use the MODIS land and ocean band reflectances simulated by ground observation data. In the band combination analysis, it was possible to substitute PRI when each growth stage of vegetation was separately analyzed. But, it was difficult to substitute PRI by a single equation in all growth stages. In the multiple regression analysis, it was possible to substitute PRI using the logarithm of MODIS land and ocean band reflectances even when all growth stages were analyzed at the same time. Second, we verified accuracy of alternative index by the multiple regression analysis by applying ground data acquired in different years and sites. It was found that the error of PRI was 0.0112 (RMSE) and this corresponds to 10% error of LUE.
