Solar‐induced chlorophyll fluorescence that correlates with canopy photosynthesis on diurnal and seasonal scales in a temperate deciduous forest

Abstract

Previous studies have suggested that solar‐induced chlorophyll fluorescence (SIF) is correlated with Gross Primary Production (GPP). However, it remains unclear to what extent this relationship is due to absorbed photosynthetically active radiation (APAR) and/or light use efficiency (LUE). Here we present the first time series of near‐surface measurement of canopy‐scale SIF at 760 nm in temperate deciduous forests. SIF correlated with GPP estimated with eddy covariance at diurnal and seasonal scales (r2 = 0.82 and 0.73, respectively), as well as with APAR diurnally and seasonally (r2 = 0.90 and 0.80, respectively). SIF/APAR is significantly positively correlated with LUE and is higher during cloudy days than sunny days. Weekly tower‐based SIF agreed with SIF from the Global Ozone Monitoring Experiment‐2 (r2 = 0.82). Our results provide ground‐based evidence that SIF is directly related to both APAR and LUE and thus GPP, and confirm that satellite SIF can be used as a proxy for GPP.

New Spectral Fitting Method for Full-Spectrum Solar-Induced Chlorophyll Fluorescence Retrieval Based on Principal Components Analysis

“…The results show that the double-peak characteristic of the SIF spectrum has been successfully reconstructed; the diurnal variation trend in the SIF is also reasonable and consistent with the results from literature (e.g. [40][41][42]). …”

Reconstructed Solar‐Induced Fluorescence: A Machine Learning Vegetation Product Based on MODIS Surface Reflectance to Reproduce GOME‐2 Solar‐Induced Fluorescence

“…SIF has a small‐amplitude signal, so it was not possible to observe it until very recently. SIF observations have been shown to be directly pertinent to estimate crop photosynthesis (Guanter et al, 2014) and yield (Guan et al, 2016), GPP across ecosystems (Lee et al, 2015; Yang et al, 2015; Zhang, Xiao, Jin, et al, 2016), water stress (Guan et al, 2015; Konings et al, 2017; Sun et al, 2015; Zhang, Xiao, Guanter, et al, 2016), biosphere‐atmosphere interactions (Green et al, 2017), surface turbulent fluxes (Alemohammad et al, 2017), and phenology, especially in northern latitudes where vegetation indices and their seasonality are polluted by the snow albedo (Jeong et al, 2017). One other advantage of SIF is that it responds to only the PAR absorbed by chlorophyll of the canopy, whereas typical optical (absorbed photosynthetic active radiation) APAR or fPAR products reflect the PAR absorbed by the entire canopy (nonphotosynthetic and photosynthetic; Song et al, 2013).…”

The quest for understanding phenotypic variation via integrated approaches in the field environment

“…The use of solar-induced chlorophyll fluorescence, based on the Fraunhofer line discrimination principle (Plascyk, 1975;Meroni et al, 2009), was recently implemented successfully using UAS-based hyperspectral imagery for the early detection of Verticillium wilt in a production olive (Olea europaea) orchard (Calderón et al, 2013). As an extension of this technology to ecological studies, the relationship of chlorophyll fluorescence to gross primary production has enabled the assessment of temporal changes in ecosystem health and productivity in response to climatic change (Damm et al, 2015;Yang et al, 2015). Although fluorescence imaging is promising, it still suffers from the same limitations as other spectral imaging techniques, including inconsistent or uneven illumination, wind disturbances under field conditions, and being unable to discriminate the underlying cause of the stress.…”