Solar-induced fluorescence mapping with high resolution satellite imaging spectrometers

SIF is closely related to gross primary productivity (GPP) at ecosystem scale, but low spatial resolution of existing satellite limits the understanding of the relationship between SIF and GPP at different spatial and temporal scales. A new generation of terrestrial and airborne observation systems with high spatial and spectral resolution has been widely used. The future satellite FLEX has 300 m spatial resolution, but SIF signal is less than 5% of the background signal, so strict instrument characterization is necessary for reducing SIF retrieval error. In this study, satellite radiance products were simulated using airborne hyperspectral imaging spectrometer data of the HyPlant, and then the pixel of satellite image were aggregated to 10m, 30m, 50m respectively, and SIF of the merged images was retrieved and analyzed. The results show that SIF signal can be retrieved from simulated satellite images with different spatial resolutions, and the retrieval SIF has a good correlation with that retrieved from the original HyPlant image. We also find that the detail of SIF in image gradually smoothed out with the decrease of spatial resolution, and the SIF retrieval error decreased simultaneously. The results of this study also reveal the importance of high spatial resolution satellite imaging spectrometer to detect and quantify SIF.