Assessing the factors determining the relationship between solar-induced chlorophyll fluorescence and GPP

Remote measurement of SIF has opened a new perspective to assess plant actual photosynthesis at larger, ecologically relevant scales. However, understanding the underling mechanisms between SIF and GPP remains challenging before SIF used as a robust constraint for estimating GPP. In this study, GOME-2 SIF was found to be consistently related to MODIS GPP. We also noticed the SIF-GPP relationship was ecosystem-specific and influenced by land surface temperature. The former was due to some structural and physiological characteristics related to each ecosystem. The latter can be attributed to the biochemical process influenced by temperature conditions. Model simulations also indicated the SIF-GPP relationship was complex and affected by some factors like chlorophyll content and LAI. Our study contributes to a better understanding of the information inherent in remotely sensed SIF and its functional relationship to GPP.