Investigating the Performance of Red and Far-Red SIF for Monitoring GPP of Alpine Meadow Ecosystems

Alpine meadow ecosystems are extremely vulnerable to climate change and serve an essential function in terrestrial carbon sinks. Accurately estimating their gross primary productivity (GPP) is for understanding the global cycle. Solar-induced chlorophyll fluorescence (SIF), as a companion product directly related plant photosynthesis process, has become attractive pathway GPP accurately. To date, quantitative SIF-GPP relationship not yet clear. Especially, red SIF far-red present differences ability track under different environmental conditions. In this study, we investigated performance of at both band monitoring alpine ecosystem based on continuous tower-based observations 2019 2020. The results show that canopy (SIFRed) (SIFFar-red) were strongly correlated with GPP. SIFRed was comparable SIFFar-red comparisons half-hourly averaged daily datasets. Moreover, between linearly correlated, while tended be nonlinear. At diurnal scale, dramatic changes photosynthetically active radiation (PAR), air temperature (Ta), vapor pressure deficit (VPD) all had effects slope linear fitted line zero intercept SIFRed-GPP SIFFar-red-GPP, effect SIFFar-red-GPP obviously stronger than SIFRed-GPP. PAR dominant factor among three factors determining variation SIF-GPP. seasonal SIFFar-red/GPP susceptible PAR, Ta, VPD, SIFRed/GPP remained relatively stable levels Ta it only weakly affected by suggesting more consistent response variations factors. These indicate potential can also assist researchers gaining comprehensive diversity relationships ecosystems.