A precise method unaffected by atmospheric reabsorption for ground-based retrieval of red and far-red sun-induced chlorophyll fluorescence

•PLS retrieves red and far-red SIF with high precision and atmospheric robustness.•Broad fitting window 610 nm–850 nm exploits solar Fraunhofer lines.•Synthetic data trains PLS model from SCOPE simulated SIF and reflectance.•PLS retrieval agrees with reference in synthetic and measured data.•Positive and meaningful SIF is retrieved in despite of 100m atmospheric column.