Alesse et al. (2026) Satellite-based assessment of hydrologic synchronization across Western U.S. basins: Implications for water security

Identification

• Journal: Journal of Hydrology Regional Studies
• Year: 2026
• Date: 2026-09-05
• Authors: Calef Alesse, Thomas C. Piechota, Josh Fuery, Landon Kauer, V. Lakshmi
• DOI: 10.1016/j.ejrh.2026.103891

Research Groups

• Chapman University, Fowler School of Engineering and Schmid College of Science and Technology
• Johns Hopkins University, Environmental Health and Engineering

Short Summary

This study examines the hydrologic synchronization across Western U.S. basins using satellite datasets and analytical methods to identify spatial patterns, synchronized extremes, and lead-lag relationships.

Objective

• Investigate the temporal co-variability of hydrologic conditions across multiple basins in the Western United States.
• Quantify hydrologic synchronization using statistical measures of strength, timing, and persistence of hydrologic variability across large spatial scales.

Study Configuration

• Spatial Scale: The study focuses on five HUC2 watersheds (Upper Colorado, Lower Colorado, Great Basin, California, Pacific Northwest) and 44 HUC4 sub-basins in the Western United States.
• Temporal Scale: The analysis covers a period of 2000-2024.

Methodology and Data

• Models used:
  • GLDAS (Global Land Data Assimilation System)
  • PRISM (Parameter–Elevation Regressions on Independent Slopes Model)
  • SMAP (Soil Moisture Active Passive)
• Data sources:
  • Satellite datasets from GLDAS, PRISM, and SMAP
  • Observational runoff data from Lees Ferry and The Dalles

Main Results

• Hydrologic synchronization is observed across the Western United States, with some regions showing strong correlations (e.g., California-Great Basin pair shows 65% runoff synchronization).
• Synchronized extremes occur every 3-4 years (~25% of months), suggesting that multi-basin droughts are an intrinsic feature of western hydroclimate.
• PCA identifies four spatially coherent regions: coastal Pacific Northwest, arid Southwest, coastal California, and northern Rockies.

Contributions

• This study provides a comprehensive characterization of synchronization across the Western United States using a multi-variable approach.
• The results highlight the importance of considering multiple variables when assessing hydrologic synchronization.

Funding

• Not specified in the provided text.

Citation

@article{Alesse2026Satellitebased,
  author = {Alesse, Calef and Piechota, Thomas C. and Fuery, Josh and Kauer, Landon and Lakshmi, V.},
  title = {Satellite-based assessment of hydrologic synchronization across Western U.S. basins: Implications for water security},
  journal = {Journal of Hydrology Regional Studies},
  year = {2026},
  doi = {10.1016/j.ejrh.2026.103891},
  url = {https://doi.org/10.1016/j.ejrh.2026.103891}
}