Zhai et al. (2026) Adapting the temperature-fluorescence dryness index as a functional ecological indicator for tracking agroecosystem drought in China's winter wheat regions

Identification

• Journal: Ecological Indicators
• Year: 2026
• Date: 2026-09-26
• Authors: Yaming Zhai, Mingyi Huang, Wei Du, Chengli Zhu, Chang Xu, Junfeng Zhang, Minglun Zhang, Yifan Liu
• DOI: 10.1016/j.ecolind.2026.115573

Research Groups

• Hohai University College of Agricultural Science and Engineering, China

Short Summary

This study adapts the Temperature-Fluorescence Dryness Index (TFDI) as a functional ecological indicator for tracking agroecosystem drought in China's winter wheat regions. The TFDI integrates land surface temperature and solar-induced chlorophyll fluorescence to monitor drought conditions.

Objective

• Investigate the performance of TFDI in capturing agroecosystem drought dynamics across China's major winter-wheat regions during 2003–2022.
• Evaluate the relative importance of climatic, edaphic, and topographic variables associated with TFDI trends using XGBoost and observed-variable path modeling.

Study Configuration

• Spatial Scale: The study area spans a vast geographical range from 26◦N to 50◦N and 75◦E to 122◦E, including 11 provinces in China.
• Temporal Scale: The study period covers the winter wheat growing seasons (March–May) from 2003 to 2022.

Methodology and Data

• Models used: Temperature-Fluorescence Dryness Index (TFDI), XGBoost, observed-variable path modeling.
• Data sources:
  • HCSIF dataset for SIF data
  • MODIS products for LST and NDVI
  • ERA5-Land Daily Aggregated dataset for meteorological variables
  • SMCI1.0 dataset for soil moisture at 0–10 cm and 10–20 cm
  • ESA CCI surface soil-moisture product for complementary validation
  • GLDAS Noah Land Surface Model L4 product for multi-layer soil moisture simulations
  • CHM_Drought dataset for meteorological drought conditions and VPD

Main Results

• The TFDI showed improved performance in capturing agroecosystem drought dynamics compared to the traditional Temperature Vegetation Dryness Index (TVDI).
• The study found that atmospheric evaporative-demand variables had greater model-attributed importance in northern regions, whereas precipitation had greater importance in southern regions.
• The results indicated a mean Sen slope of 0.0092 yr−1 for the annual March–May TFDI series, with FDR-significant positive TFDI trends (drying) across 40.37% of the persistent winter-wheat domain.

Contributions

• This study provides a systematic evaluation of the Temperature-Fluorescence Dryness Index (TFDI) as an ecological drought indicator for agroecosystem monitoring.
• The results highlight the importance of integrating land surface temperature and solar-induced chlorophyll fluorescence to capture drought dynamics across diverse environmental settings.

Funding

• This research was funded by [project name], [program name], and [reference code].

Citation

@article{Zhai2026Adapting,
  author = {Zhai, Yaming and Huang, Mingyi and Du, Wei and Zhu, Chengli and Xu, Chang and Zhang, Junfeng and Zhang, Minglun and Liu, Yifan},
  title = {Adapting the temperature-fluorescence dryness index as a functional ecological indicator for tracking agroecosystem drought in China's winter wheat regions},
  journal = {Ecological Indicators},
  year = {2026},
  doi = {10.1016/j.ecolind.2026.115573},
  url = {https://doi.org/10.1016/j.ecolind.2026.115573}
}