Application of the Photochemical Reflectance Index to Track Light Use Efficiency with a Two-Leaf Model

Proper determination of light use efficiency (LUE) is a prerequisite for LUE models to simulate gross primary productivity (GPP). This study was devoted to apply the photochemical reflectance index (PRI) to accurately track LUE variations for a sub-tropical coniferous forest using tower-based PRI and GPP measurements. To improve the ability of PRI to track LUE, a simple two-leaf approach is used to process the remote sensing and flux data. The results showed: both PRI and LUE decreased with increases of bioclimatic factors. PRI is able to capture diurnal and seasonal changes in LUE. And the two-leaf approach significantly enhanced the correlation between PRI and LUE at either half-hourly or daily time steps.