NIRVP: A robust structural proxy for sun-induced chlorophyll fluorescence and photosynthesis across scales

Sun-induced chlorophyll fluorescence (SIF) is a promising new tool for remotely estimating photosynthesis. However, the degree to which incoming solar radiation and structure of canopy rather than leaf physiology contribute SIF variations still not well characterized. Therefore, we investigated relationships between variables that at least partly capture component SIF. For this, relied on high-quality observations from ground-based instruments, high-resolution airborne imagery most recent satellite products cover large ranges in spatial temporal resolution diverse ecosystems. We found structure-related near-infrared reflectance vegetation multiplied by sunlight (NIRVP) robust proxy far-red across wide range scales. Our findings indicate contributions variability are small compared components. Also, NIRVP captured spatio-temporal patterns photosynthesis better SIF, seems be mostly due greater retrieval noise Compared other relevant structural proxies, showed more especially global scale. results highlight promise using widely available data monitoring also potential combination extract physiological information