Understanding uncertainties in the satellite altimeter measurement of coastal sea level: insights from a round-robin analysis

Birol, Florence; Bignalet-Cazalet, François; Cancet, Mathilde; Daguze, Jean-Alexis; Fkaier, Wassim; Fouchet, Ergane; Léger, Fabien; Maraldi, Claire; Niño, Fernando; Pujol, Marie-Isabelle; Tran, Ngan

doi:https://doi.org/10.5194/os-21-133-2025

Articles | Volume 21, issue 1

https://doi.org/10.5194/os-21-133-2025

© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/os-21-133-2025

© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 21, issue 1

Research article

|

24 Jan 2025

Research article |

| 24 Jan 2025

Understanding uncertainties in the satellite altimeter measurement of coastal sea level: insights from a round-robin analysis

Florence Birol, François Bignalet-Cazalet, Mathilde Cancet, Jean-Alexis Daguze, Wassim Fkaier, Ergane Fouchet, Fabien Léger, Claire Maraldi, Fernando Niño, Marie-Isabelle Pujol, and Ngan Tran

Data sets

Tide gauge observations BODC https://www.bodc.ac.uk/data/hosted_data_systems/sea_level/uk_tide_gauge_network/processed/

Tide gauge observations Bureau Of Meteorology http://www.bom.gov.au/oceanography/projects/abslmp/data/index.shtml

Sea level measured by tide gauges from global oceans - the Joint Archive for Sea Level holdings P. C. Caldwell et al. https://doi.org/10.7289/V5V40S7

CNES_CLS 2022 Mean Sea Surface CLS https://doi.org/10.24400/527896/A01-2022.017

Jason-2 Geophysical Data Record CNES https://www.aviso.altimetry.fr/en/data/products/sea-surface-height-products/global/gdr-igdr-and-ogdr.html

Jason-3 Geophysical Data Record CNES https://www.aviso.altimetry.fr/en/data/products/sea-surface-height-products/global/gdr-igdr-and-ogdr.html

Global Ocean - Delayed Mode Sea level product E.U. Copernicus Marine Service Information https://doi.org/10.17882/93670

GPD+ Wet Tropospheric Correction M. J. Fernandes et al. https://doi.org/10.23831/FCUP_UPORTO_GPDPlus_v1.0

EOT20 - A global Empirical Ocean Tide model from multi-mission satellite altimetry M. Hart-Davis et al. https://doi.org/10.17882/79489

Tide gauge observations ISPRA https://www.mareografico.it/en/data-archive.html

Tide gauge observations REFMAR https://doi.org/10.17183/REFMAR#RONIM

Model code and software

Coastal Altimetry Round Robin reports Groupe de Travail en Altimétrie côtière https://www.aviso.altimetry.fr/en/data/products/sea-surface-height-products/global/altimetry-innovative-coastal-approach-product-alticap/roundrobin-reports.html

Short summary

We take advantage of the availability of several algorithms for most of the terms/corrections used to calculate altimetry sea level data to quantify and analyze the sources of uncertainty associated with the approach to the coast. The results highlight their hierarchy. Tidal corrections and mean sea surface height contribute to coastal sea level data uncertainties. Improving the retracking algorithm is today the main factor to bring accurate altimetry sea level data closer to the shore.