Prototype of a weekly SIF-based proxy for GPP over Europe

In the past 15 years, solar-induced chlorophyll fluorescence (SIF) has been retrieved from spaceborne remote sensing instruments destined for atmospheric studies. This retrieved variable has shown an apparently strong linear relationship with gross primary productivity (GPP) at the global scale, suggesting a strong potential to establish satellite-based estimations of ecosystem productivity. However, this relationship is not consistent across ecosystems and can break down under stress conditions, raising limitation about its application. The relationship is known to vary with respect to radiation intensity, vegetation structure and physiological conditions. Thus, it has been proposed to reason in terms of quantum efficiency of SIF (SIF yield, φF), rather than SIF itself, in order to isolate the physiological signal that should give the additional information regarding GPP that is not already get from vegetation indices combined with radiation. In this experimental product developed within NextGenCarbon, we are combining difference sources of satellite remote sensing to try to establish a weekly product of φF at European scale. We are providing a first prototype of what this product will look like. It will then be improved during the course of the project towards a final refined product.