Predicting the carbon-climate feedbacks relies on the accurate estimation of terrestrial gross primary productivity (GPP), the largest CO2 flux on Earth. Recent works showed that there is a large uncertainty in estimating the magnitude, timing, and inter-annual variability of GPP, suggesting there is a challenge to upscale leaf-level processes to global scales using satellite remote sensing or earth system models. One main reason for this uncertainty is the lack of observations of GPP at the relevant scales. Solar-induced chlorophyll fluorescence (SIF) shows promising results in capturing the spatial and temporal variability of GPP.
Results/Conclusions
Here I provide an integrated model-observation framework that assesses SIF as a novel indicator of GPP from leaf to ecosystem scales. Insights from a network of ground-based fluorescence sensors (FluoNet) can help us understand the physiological, directional, and structural controls over the SIF-GPP relationship at different spatial and temporal scales. Novel observations from drones and airplanes provide the means to upscale leaf-level observations to the satellite scale.