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.