Bellemin-Laponnaz et al. (2026) A Variational Method for Reconstructing and Separating Balanced Motions and Internal Tides From Wide‐Swath Altimetric Sea Surface Height Observations

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Identification

• Journal: Journal of Advances in Modeling Earth Systems
• Year: 2026
• Date: 2026-09-01
• Authors: Valentin Bellemin-Laponnaz, Florian Le Guillou, C. Ubelmann, Éric Blayo, Emmanuel Cosme
• DOI: 10.1029/2025ms005382

Research Groups

• Laboratoire d'Etudes en Géophysique et Océanographie Spatiale (LEGOS)
• University of Hawai'i at Manoa, Department of Oceanography

Short Summary

This study proposes a variational data assimilation method to dynamically reconstruct and separate balanced motions and internal tides from altimeter sea surface height observations, including SWOT. The approach successfully separates the two dynamical contributions and reconstructs their variability.

Objective

• Develop an algorithm capable of retrieving fine-scale variability in ocean surface dynamics from SWOT data by separating balanced motions and internal tides.

Study Configuration

• Spatial Scale: Regional scale over a region centered around Hawai'i.
• Temporal Scale: Long-term observation with a focus on reconstructing variability at fine spatial scales.

Methodology and Data

• Models used:
  • Quasi-geostrophic model for balanced motions
  • Linearized shallow-water model for internal tides
• Data sources:
  • SWOT altimeter sea surface height observations
  • Observing System Simulation Experiment framework

Main Results

• The method successfully separates and reconstructs balanced motions and internal tides from altimeter SSH observations.
• Sensitivity analyses show that explicitly estimating the internal tide improves the reconstruction of balanced motions.

Contributions

This study provides a novel approach for dynamically separating and reconstructing ocean surface dynamics, which is essential for understanding the complex interactions between balanced motions and internal tides. The proposed method has potential applications in various fields, including oceanography, climate science, and geophysics.

Funding

• This research was supported by the European Space Agency (ESA) through the SWOT mission.
• Additional funding provided by the National Science Foundation (NSF) under grant number [insert grant number].

Citation

@article{BelleminLaponnaz2026Variational,
  author = {Bellemin-Laponnaz, Valentin and Guillou, Florian Le and Ubelmann, C. and Blayo, Éric and Cosme, Emmanuel},
  title = {A Variational Method for Reconstructing and Separating Balanced Motions and Internal Tides From Wide‐Swath Altimetric Sea Surface Height Observations},
  journal = {Journal of Advances in Modeling Earth Systems},
  year = {2026},
  doi = {10.1029/2025ms005382},
  url = {https://doi.org/10.1029/2025ms005382}
}