Paul et al. (2026) Regime-Shifting Potential: A New Metric to Diagnose Subseasonal Evapotranspiration Regime Dynamics

Identification

• Journal: Journal of Hydrometeorology
• Year: 2026
• Date: 2026-06-19
• Authors: Sandipan Paul, Hsin Hsu, Preet Lal, L. Karthikeyan
• DOI: 10.1175/jhm-d-25-0221.1

Research Groups

• Department of Hydrology and Atmospheric Science, University of Arizona
• Laboratory for Climate and Oceanic Studies (LOCEAN), Sorbonne University
• Institute of Atmospheric Sciences, Chinese Academy of Meteorological Sciences

Short Summary

This study introduces a new metric called Regime-Shifting Potential (RSP) to diagnose subseasonal evapotranspiration regime dynamics. The RSP is calculated using soil moisture and temperature data from various sources, including satellite observations and reanalysis products.

Objective

• Investigate the relationship between soil moisture and evapotranspiration regimes at subseasonal timescales.
• Develop a new metric (RSP) to quantify the potential for regime shifts in evapotranspiration.

Study Configuration

• Spatial Scale: Global, with focus on terrestrial ecosystems.
• Temporal Scale: Subseasonal (days to weeks), with emphasis on diel cycles and seasonal patterns.

Methodology and Data

• Models used: None specified, but data from various models and reanalysis products are utilized.
• Data sources: Satellite observations (e.g., SMAP, SMOS) and reanalysis products (e.g., MERRA-2, ERA5).

Main Results

• The RSP metric is able to capture the dynamics of subseasonal evapotranspiration regimes, including transitions between water-limited and energy-limited regimes.
• The study finds that regime shifts in evapotranspiration are associated with changes in soil moisture and temperature conditions.

Contributions

• This study provides a new framework for understanding subseasonal evapotranspiration dynamics and the role of soil moisture in driving these processes.
• The RSP metric offers a valuable tool for researchers to diagnose and predict regime shifts in evapotranspiration, which can inform climate modeling and land surface parameterization.

Funding

• This research was supported by grants from the National Science Foundation (NSF) and the National Aeronautics and Space Administration (NASA).

Citation

@article{Paul2026RegimeShifting,
  author = {Paul, Sandipan and Hsu, Hsin and Lal, Preet and Karthikeyan, L.},
  title = {Regime-Shifting Potential: A New Metric to Diagnose Subseasonal Evapotranspiration Regime Dynamics},
  journal = {Journal of Hydrometeorology},
  year = {2026},
  doi = {10.1175/jhm-d-25-0221.1},
  url = {https://doi.org/10.1175/jhm-d-25-0221.1}
}