Detecting drought stress occurrence using synergies between Sun induced fluorescence and vegetation surface temperature spatial records

Zoltán Nagy; János Balogh; Dóra Petrás; Szilvia Fóti; Alasdair MacArthur; Krisztina Pintér

doi:10.1016/j.scitotenv.2023.168053

Detecting drought stress occurrence using synergies between Sun induced fluorescence and vegetation surface temperature spatial records

Sci Total Environ. 2024 Jan 10:907:168053. doi: 10.1016/j.scitotenv.2023.168053. Epub 2023 Oct 26.

Authors

Zoltán Nagy¹, János Balogh², Dóra Petrás², Szilvia Fóti³, Alasdair MacArthur⁴, Krisztina Pintér⁵

Affiliations

¹ Department of Plant Physiology and Plant Ecology, Agronomy Institute, Hungarian University for Life and Agriculture, 2100 Gödöllő, Páter 1., Hungary; HUN-REN-MATE Agroecology Research Group, 2100 Gödöllő, Páter 1., Hungary. Electronic address: nagy.zoltan@uni-mate.hu.
² Department of Plant Physiology and Plant Ecology, Agronomy Institute, Hungarian University for Life and Agriculture, 2100 Gödöllő, Páter 1., Hungary.
³ Department of Plant Physiology and Plant Ecology, Agronomy Institute, Hungarian University for Life and Agriculture, 2100 Gödöllő, Páter 1., Hungary; HUN-REN-MATE Agroecology Research Group, 2100 Gödöllő, Páter 1., Hungary.
⁴ University of Valencia, Spain.
⁵ HUN-REN-MATE Agroecology Research Group, 2100 Gödöllő, Páter 1., Hungary.

PMID: 37898200
DOI: 10.1016/j.scitotenv.2023.168053

Abstract

Drought stress occurrence and recovery from drought can be detected using a single spatial set of simultaneous observations of SIF and canopy temperature records. Temporal and spatial responses to drought and heat stresses by plant stands of a drought-adapted diverse grassland ecosystem were studied using sun induced fluorescence (SIF,O₂A and O₂B bands) and further ecophysiological (canopy temperature (Tsurf), spatially modeled evapotranspiration, vegetation reflectance spectra) variables collected along spatial sampling grids while also utilizing eddy covariance measured carbon dioxide (net ecosystem exchange: NEE, gross primary production: GPP) and water flux (evapotranspiration: ET) data. The grids were of 0.5 and 5 ha spatial extents and contained 78 sampling points. Data were collected in four spatial sampling campaigns, two under drought (early summer) and another two during and after recovery (midsummer) at both spatial resolutions. Small values of spatial SIF_A averages (around 0.5 mW m^-2 nm^-1 sr^-1) under strong early summer drought increased (to around 2 mW m^-2 nm^-1 sr^-1) due recovery upon rain arrivals, showing high (R²: 0.8-0.88) positive temporal correlations to eddy covariance measured carbon (GPP, NEE) and water (ET) fluxes. Spatial averages of LAI, vegetation indices (NDVI, NIRv) and modeled ET followed similar temporal patterns. While SIF was depressed by drought, it showed higher values in high canopy temperature vegetation patches than in vegetation patches with lower Tsurf. The spatial pattern of higher SIF in higher Tsurf patches was persistent (2 weeks) under drought. The positive SIF_A-Tsurf spatial correlation turned into negative/not significant after recovery of the grassland from the drought, while hot summer weather persisted. It is proposed that, by using a single set of simultaneously measured spatial SIF and Tsurf data it is possible to infer whether the studied vegetation is under drought (and heat) stress while it could not be decided on the base of SIF data alone. Evaluation of the slope of the above relationship seems therefore beneficial before e.g. starting the (stress) classification procedure based on SIF.

Keywords: Canopy surface temperature; SIF; Spatial stress characterization.

MeSH terms

Droughts*
Ecosystem*
Environmental Monitoring
Fluorescence
Seasons
Temperature
Water

Substances

Water