Hancock et al. (2026) 21st century hydrological trends in the Mississippi River basin intensify the east to west moisture gradient

⚠️ Warning: This summary was generated from the abstract only, as the full text was not available.

Identification

• Journal: Journal of Climate
• Year: 2026
• Date: 2026-03-09
• Authors: Christopher L. Hancock, Sylvia G. Dee, Muhammad Rezaul Haider, James Doss-Gollin, Flavio Lehner, Kelsey Murphy, Samuel E. Muñoz
• DOI: 10.1175/jcli-d-25-0340.1

Research Groups

Not available in the abstract.

Short Summary

This study validates 19 CMIP6 models against historical observations to project future monthly hydroclimate changes in the Mississippi River system under the SSP3-7.0 pathway. It finds consistent increases in precipitation but decreases in soil moisture due to enhanced evaporative demand, with highly divergent and regionally varied trends for runoff and discharge driven by large-scale atmospheric and oceanic patterns.

Objective

• To understand monthly hydroclimate changes in the Mississippi River system using the SSP3-7.0 pathway, by validating and examining 19 models from CMIP6.

Study Configuration

• Spatial Scale: Mississippi River system (draining 41% of the contiguous United States), including eastern sub-basins, Missouri River sub-basin, Ohio sub-basin, and western tributaries.
• Temporal Scale: Monthly hydroclimate changes, examining future projections under the SSP3-7.0 pathway, validated against historical observations.

Methodology and Data

• Models used: 19 models from the Sixth Phase of the Coupled Model Intercomparison Project (CMIP6), river transport models.
• Data sources: Historical observations (for model validation).

Main Results

• Models consistently project an increase in precipitation throughout the Mississippi River basin.
• Soil moisture is projected to decrease in all seasons due to increasing evaporative demand.
• Precipitation minus evapotranspiration (P-ET), runoff, and discharge simulated by river transport models show poor constraint and differing trends across regions and models.
• Runoff increases are more robust for the eastern sub-basins, where precipitation anomalies are higher.
• Drying trends are more likely for the Missouri River sub-basin.
• Models projecting increased runoff within the Mississippi River basin exhibit stronger ENSO-related Pacific warming, enhanced North Atlantic Subtropical High development, and increased moisture transport into the Ohio sub-basin.
• Models projecting drying trends show weaker Pacific warming and circulation changes, with precipitation and runoff declines concentrated in the western tributaries.

Contributions

• Highlights the critical role of large-scale atmospheric and oceanic drivers in shaping the divergent hydroclimate projections for the Mississippi River Basin.
• Provides insights into regional variations in future hydroclimate trends and the agreement/disagreement among CMIP6 models for this heavily engineered river system.

Funding

Not available in the abstract.

Citation

@article{Hancock202621st,
  author = {Hancock, Christopher L. and Dee, Sylvia G. and Haider, Muhammad Rezaul and Doss-Gollin, James and Lehner, Flavio and Murphy, Kelsey and Muñoz, Samuel E.},
  title = {21st century hydrological trends in the Mississippi River basin intensify the east to west moisture gradient},
  journal = {Journal of Climate},
  year = {2026},
  doi = {10.1175/jcli-d-25-0340.1},
  url = {https://doi.org/10.1175/jcli-d-25-0340.1}
}