Towards advanced retrievals of plant transpiration using sun-induced chlorophyll fluorescence: first considerations

Reliable information about plant transpiration (T) is essential to advance understanding of various interactions and feedbacks across Earth spheres and eventually facilitate their predictions. Estimating T at larger scales is particularly challenged by the difficulty to constrain the biological control on T (i.e. stomatal conductance), while existing approaches based on potential rather than actual photosynthesis are less reliable than required. New Earth observation approaches such as measurements of sun induced chlorophyll fluorescence (SIF), the most direct observable of ecosystem photosynthesis, opens new perspectives to advance estimates of T. This contribution aims to sensitize for variability of SIF-T relationships across species and in dependency on environmental conditions. We use the combined energy balance and radiative transfer model SCOPE to assess relationships between SIF and T in dependency on relevant environmental and plant specific variables. Our results provide important insight to further define SIF based approaches for advanced estimates of T