Clarifying linkages between canopy solar induced fluorescence (SIF) and physiological function for high latitude vegetation

Abstract

Remote sensing of Solar-Induced Fluorescence (SIF) is a growing and dynamic research field that has the potential to provide innovative tools for monitoring plant status and photosynthetic function and transform global carbon cycle research, especially for large and understudied regions like the ABoVE domain. Utilizing SIF to its full extent requires an understanding of the relationship between SIF and the photosynthetic function of the vegetation present, and how these vary with plant type and environmental conditions. High latitudes have been under-represented in SIF studies to date, but arctic and boreal plants are particularly interesting as they have photosynthetic properties and environmental responses that appear to be different to those described from better-studied temperate vegetation. We will examine the relationship between SIF and vegetation photosynthetic capacity from the plot to landscape level at multiple locations within the ABoVE domain. Measurements will include multi-temporal sampling of leaf and canopy chlorophyll fluorescence (ChlF) and photosynthesis for a range of plant communities, plant functional types, and species present along environmental gradients and in experimental manipulations at each location. Higher temporal frequency measurements w will be made using automated sensors at select locations and subsampling will focus on quantifying spatiotemporal heterogeneity in SIF emissions. Relationships of red and far red ChlF (and spectral reflectance) with plant biophysical status derived from the field studies will be established and scaled up using both empirical approaches and physically-based modeling to provide the critical information linking canopy SIF and photosynthetic function needed for interpreting satellite SIF data for high latitude ecosystems. The satellite data record will be used to examine the spatial and temporal variability of high latitude ecosystem function and carbon uptake across the ABoVE domain