Tang et al. (2026) Dynamic-programming-based subwaveform retracking with along-track constraints for inland river water level retrieval from Sentinel-3 altimetry

Identification

• Journal: Journal of Hydrology
• Year: 2026
• Date: 2026-10-07
• Authors: Minjun Tang, Lihua Xiong
• DOI: 10.1016/j.jhydrol.2026.136586

Research Groups

State Key Laboratory of Water Resources Engineering and Management, Wuhan University, Wuhan, PR China

Short Summary

This study proposes a dynamic-programming-based subwaveform retracking (DPSR) method that transforms conventional footprint-wise retracking into an along-track global optimization problem for river water level retrieval. Evaluated over the Amazon and Poyang Lake basins, DPSR outperforms benchmark methods, achieving a median RMSE of 0.41 m and improving data availability by approximately 39%.

Objective

• To develop a robust method for accurate inland river water level retrieval from Sentinel-3 altimetry by addressing the challenge of contaminated waveforms and complex subwaveform identification.

Study Configuration

• Spatial Scale: Amazon basin (78 gauge-virtual station pairs), Poyang Lake basin (39 gauge-virtual station pairs).
• Temporal Scale: Sentinel-3 altimetry data for inland river water level monitoring. (Specific time range of data used for evaluation not provided in the abstract.)

Methodology and Data

• Models used: Dynamic-programming-based subwaveform retracking (DPSR). Compared with: threshold retracking, Offset Centre of Gravity (OCOG), Brown model, SAMOSA, ALES, TIC, CTR, IMSA.
• Data sources: Sentinel-3 altimetry data, in-situ gauge data for validation.

Main Results

• DPSR outperforms all benchmark retracking methods.
• Achieved a median Root Mean Square Error (RMSE) of 0.41 m.
• RMSE decreased by 0.02–1.2 m compared with other methods.
• Improved data availability by approximately 39% relative to benchmark retrackers.
• DPSR demonstrated particularly strong performance in narrow rivers.

Contributions

• Introduces a novel dynamic-programming-based subwaveform retracking (DPSR) method that redefines retracking as an along-track global optimization problem.
• Integrates spatial constraints into subwaveform interpretation, enhancing the selection of physically consistent subwaveforms from contaminated observations.
• Provides a robust solution for satellite altimetry retrieval of river water levels, especially in complex environments and narrow rivers.
• Significantly improves both the accuracy and data availability of inland river water level products from Sentinel-3 altimetry.

Funding

Not mentioned in the provided text.

Citation

@article{Tang2026Dynamicprogrammingbased,
  author = {Tang, Minjun and Xiong, Lihua},
  title = {Dynamic-programming-based subwaveform retracking with along-track constraints for inland river water level retrieval from Sentinel-3 altimetry},
  journal = {Journal of Hydrology},
  year = {2026},
  doi = {10.1016/j.jhydrol.2026.136586},
  url = {https://doi.org/10.1016/j.jhydrol.2026.136586}
}