Jia et al. (2025) Sensitivity of thermal evapotranspiration models to surface and atmospheric drivers across ecosystems and aridity

Identification

• Journal: Agricultural and Forest Meteorology
• Year: 2025
• Date: 2025-11-15
• Authors: Aolin Jia, Kaniska Mallick, Ziyu Lin, Mauro Sulis, Zoltan Szantoi, Lilin Zhang, Chiara Corbari, Práxedes Muñoz, Héctor Nieto, Jean‐Louis Roujean, Jordi Etchanchu, Jérôme Demarty, Samuel Mwangi, Albert Olioso, Olivier Merlin, Gilles Boulet
• DOI: 10.1016/j.agrformet.2025.110930

Research Groups

• Remote Sensing and Natural Resources Modeling, Luxembourg Institute of Science and Technology (LIST), Belvaux, Luxembourg
• Science, Applications & Climate Department, European Space Agency, Frascati, Italy
• Department of Geography & Environmental Studies, Stellenbosch University, Stellenbosch, South Africa
• School of Earth Sciences and Engineering, Hohai University, Jiangsu, China
• Department of Civil and Environmental Engineering, Politecnico di Milano, Milan, Italy
• Instituto de Ciencias Agrarias (ICA-CSIC), Madrid, Spain
• Centre d’Etudes Spatiales de la Biosph`ere, CNES, CNRS, INRAE, IRD, UPS, Toulouse, France
• HydroSciences Montpellier (HSM), CNRS, IRD, Univ Montpellier, Montpellier, France
• Unit´e de Recherche ´ecologie des Forˆets M´editerran´ees (URFM), INRAE, Avignon, France
• UMR EMMAH, INRAE- Avignon Universit´e, Avignon, France
• Indo-French Cell for Water Sciences, ICWaR, Indian Institute of Science, Bangalore, India
• Department of Environmental Systems Sciences, ETH Zürich, Zürich, Switzerland

Short Summary

This study investigates the sensitivity of thermal-based evapotranspiration (ET) models to surface and atmospheric drivers across diverse ecosystems and aridity levels. It reveals a global transition in the dominant ET driver from soil dryness in water-limited regimes to downward solar radiation in energy-limited regimes, and quantifies the differential impacts of soil dryness and vapor pressure deficit on ET partitioning under drought conditions.

Objective

• To examine the sensitivity of evapotranspiration (ET) to key environmental drivers, including land surface temperature (LST), air temperature (TA), vapor pressure deficit (VPD), downward solar radiation (DSR), and fractional vegetation cover (FVC), using three representative thermal remote sensing (RS) models and global eddy covariance measurements.
• To understand how thermal-based ET models respond to distinct influences of soil and atmospheric water stress across various ecosystems.

Study Configuration

• Spatial Scale: Global scale, complemented by analysis at four representative sites with varying vegetation cover types.
• Temporal Scale: Seasonal variability, growing seasons, and specific drought periods compared to climatological norms.

Methodology and Data

• Models used: STIC, TSEB, SPARSE (thermal remote sensing models).
• Data sources: Global eddy covariance measurements (for validation/comparison); Remote sensing data (for LST, FVC); Atmospheric data (for TA, VPD, DSR).
• Methodology: Variance-based sensitivity analysis (Sobol’ method) was applied. A water stress test was conducted across representative sites.

Main Results

• The dominant driver of ET sensitivity transitions from water-limited to energy-limited regimes.
• Soil dryness (indicated by LST − TA) dominates ET variability up to an aridity index of 0.54 (± 0.06).
• Beyond an aridity index of 0.54 (± 0.06), downward solar radiation (DSR) becomes the primary driver of ET variability.
• Seasonal variability and ET partitioning emphasize the critical role of soil dryness in driving soil evaporation variability, particularly during growing seasons.
• ET sensitivity to soil dryness nearly doubles during drought periods compared to climatological norms at grassland sites.
• Transpiration in forests is more strongly influenced by VPD under moderate drought stress.
• Soil dryness generally exerts stronger control on ET than VPD.
• When fractional vegetation cover (FVC) exceeds 0.49, the influence of VPD anomalies on ET becomes comparable to soil dryness stress.

Contributions

• Advances the understanding of ET dynamics under increasing drought frequency and intensity.
• Highlights the potential of forthcoming high-resolution thermal-based remote sensing ET products for early drought hazard warnings, climate-resilient decision-making, and sustainable agricultural water management.
• Provides novel insights into the sensitivity of thermal-based ET models to the distinct influences of soil and atmospheric water stress across different ecosystems.

Funding

Not explicitly mentioned in the provided text.

Citation

@article{Jia2025Sensitivity,
  author = {Jia, Aolin and Mallick, Kaniska and Lin, Ziyu and Sulis, Mauro and Szantoi, Zoltan and Zhang, Lilin and Corbari, Chiara and Muñoz, Práxedes and Nieto, Héctor and Roujean, Jean‐Louis and Etchanchu, Jordi and Demarty, Jérôme and Mwangi, Samuel and Olioso, Albert and Merlin, Olivier and Boulet, Gilles},
  title = {Sensitivity of thermal evapotranspiration models to surface and atmospheric drivers across ecosystems and aridity},
  journal = {Agricultural and Forest Meteorology},
  year = {2025},
  doi = {10.1016/j.agrformet.2025.110930},
  url = {https://doi.org/10.1016/j.agrformet.2025.110930}
}