Imaging Spatial Heterogeneity of Solar-Induced Chlorophyll Fluorescence (SIF) with Very High Spatial Resolution Drone Imagery

Here, we present one of the first datasets recorded by a drone-based prototype dual camera system based on narrowband high-quality optical filters, hereafter named SIFcam. The camera allows for sensing solar-induced chlorophyll fluorescence (SIF) at 760 nm (F
760
) with centimeter ground sampling distance. The system performance was evaluated against simultaneous observations of a wheat-bean mixed canopy carried out using a mobile ground-based non-imaging system FloX (R
²
= 0.84, RMSE = 0.17 mWm
^-2
nm
^-1
sr
^-1
) and SIF imagery acquired by the airborne imager HyPlant (R
²
= 0.52, RMSE = 0.24 mWm
^-2
nm
^-1
sr
^-1
). The analysis of near-infrared reflectance allowed us to quantify on average 95.4% contribution of F
760
signal originating from sun-lit pixels of investigated canopies. Additional multispectral imagery facilitated calculation of fractional vegetation cover (FVC) of >88%. Spatial patterns of sunlit pixels are systematically consistent, indicating the plausibility of the SIFcam measurements.