Satellite altimetry reveals intensifying global river water level variability

Area of Science:

• Hydrology
• Climate Science
• Remote Sensing

Background:

• River water levels (RWLs) are critical for water management and disaster preparedness.
• Most global rivers lack sufficient monitoring (ungauged rivers).
• Satellite altimetry offers a novel approach to assess global RWL variability.

Purpose of the Study:

• To conduct a comprehensive global assessment of river water level (RWL) variability.
• To analyze spatial patterns and temporal trends in RWLs using satellite data.
• To identify changes in seasonality and extreme river flow events.

Main Methods:

• Utilized Sentinel-3A/B satellite altimetry data from 2016–2024.
• Established 46,993 virtual stations for global RWL analysis.
• Analyzed trends in maximum, minimum, and seasonal river water levels.

Main Results:

• Identified a median global RWL fluctuation of 3.76 meters.
• Observed significant RWL declines in the Americas and Western Siberia, with increases elsewhere.
• Found intensifying seasonality in 68% of basins, with maximum RWLs declining and minimum RWLs rising.

Conclusions:

• Accelerating climate pressures are driving hydrological instability and extreme river events.
• The convergence of maximum and minimum RWLs is reducing global seasonal amplitude.
• Urgent need for adaptive water management strategies to address changing river dynamics.