Integrating Solar Induced Fluorescence and the Photochemical Reflectance Index for Estimating Gross Primary Production in a Cornfield

Abstract

Abstract:The utilization of remotely sensed observations for light use efficiency (LUE) and tower-based gross primary production (GPP) estimates was studied in a USDA cornfield. Nadir hyperspectral reflectance measurements were acquired at canopy level during a collaborative field campaign conducted in four growing seasons. The Photochemical Reflectance Index (PRI) and solar induced chlorophyll fluorescence (SIF), were derived. SIF retrievals were accomplished in the two telluric atmospheric oxygen OPEN ACCESSRemote Sens. 2013, 5 6858 absorption features centered at 688 nm (O 2 -B) and 760 nm (O 2 -A). The PRI and SIF were examined in conjunction with GPP and LUE determined by flux tower-based measurements. All of these fluxes, environmental variables, and the PRI and SIF exhibited diurnal as well as day-to-day dynamics across the four growing seasons. Consistent with previous studies, the PRI was shown to be related to LUE (r 2 = 0.54 with a logarithm fit), but the relationship varied each year. By combining the PRI and SIF in a linear regression model, stronger performances for GPP estimation were obtained. The strongest relationship (r 2 = 0.80, RMSE = 0.186 mg CO 2 /m 2 /s) was achieved when using the PRI and SIF retrievals at 688 nm. Cross-validation approaches were utilized to demonstrate the robustness and consistency of the performance. This study highlights a GPP retrieval method based entirely on hyperspectral remote sensing observations.

Connection of the Photochemical Reflectance Index (PRI) with the Photosystem II Quantum Yield and Nonphotochemical Quenching Can Be Dependent on Variations of Photosynthetic Parameters among Investigated Plants: A Meta-Analysis

“…There are numerous experimental studies [49,54,66,86,90,93,96] that were devoted to the analysis of the connection between PRI and photosynthetic parameters. The results require theoretical investigations that analyze the current experimental data.…”

Gross Primary Production of a Wheat Canopy Relates Stronger to Far Red Than to Red Solar-Induced Chlorophyll Fluorescence

“…However, in their study, fluorescence measurements were acquired only at solar noon, and no information is provided about the diurnal dynamic of fluorescence and its interaction with GPP. In another study performed at ground level on a maize crop over four seasonal cycles, a much lower correlation between SIF760 and GPP was found (r 2 = 0.30) [23], which indicates that the correlation between SIF and GPP is subjected to changes, while the factors that control these variations remain unknown. Damm et al [24] analyzed the full diurnal cycle of SIF and GPP, but their investigation was limited to a short period in the season, with no major phenological vegetation changes.…”

Surface Reflectance and Sun-Induced Fluorescence Spectroscopy Measurements Using a Small Hyperspectral UAS

“…These indicators, related to vegetation energy dissipation pathways, are characterized by strong diurnal and seasonal dynamics [48][49][50]. UASs, equipped with calibrated spectrometers, could provide accurate retrieval of PRI and SIF with the necessary temporal and spatial resolution towards vegetation stress detection and modeling of gross primary productivity [51][52][53][54].…”