A strictly geostrophic product of sea-surface velocities from the SWOT fast-sampling phase

Fuente: arXiv
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Main Authors: Uchida, Takaya, Yadidya, Badarvada, Bertrand, Vadim, Chang, Jia-Xian, Arbic, Brian, Shriver, Jay, Sommer, Julien Le
Format: Preprint
Published: 2026
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author Uchida, Takaya
Yadidya, Badarvada
Bertrand, Vadim
Chang, Jia-Xian
Arbic, Brian
Shriver, Jay
Sommer, Julien Le
author_facet Uchida, Takaya
Yadidya, Badarvada
Bertrand, Vadim
Chang, Jia-Xian
Arbic, Brian
Shriver, Jay
Sommer, Julien Le
contents While geostrophy remains the simplest and most practical balance to extract velocity information from sea-surface height anomaly (SSHa), confusions remain within the oceanographic community to what extent this balance can be applied to altimetric observations with the launch of the Surface Water and Ocean Topography (SWOT) satellite. Given the limited temporal resolution of SWOT, many studies have resorted to claiming that the spatially filtered SSHa fields correspond to the geostrophic component. This introduces the ambiguity of which spatial scale to choose. Here, we build upon the recent developments in internal tide (IT) corrections (Yadidya et al., 2025) and apply a dynamic mode decomposition (DMD)-based method introduced by Lapo et al. (2025) to robustly extract the geostrophic component associated with sub-inertial frequencies from the SWOT one-day-repeat orbit; we distribute the global dataset as a public good. We provide the joint probability density function (PDF) of vorticity and strain, and spectra of SSHa at a few cross-over regions.
format Preprint
id arxiv_https___arxiv_org_abs_2601_18182
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle A strictly geostrophic product of sea-surface velocities from the SWOT fast-sampling phase
Uchida, Takaya
Yadidya, Badarvada
Bertrand, Vadim
Chang, Jia-Xian
Arbic, Brian
Shriver, Jay
Sommer, Julien Le
Atmospheric and Oceanic Physics
Data Analysis, Statistics and Probability
While geostrophy remains the simplest and most practical balance to extract velocity information from sea-surface height anomaly (SSHa), confusions remain within the oceanographic community to what extent this balance can be applied to altimetric observations with the launch of the Surface Water and Ocean Topography (SWOT) satellite. Given the limited temporal resolution of SWOT, many studies have resorted to claiming that the spatially filtered SSHa fields correspond to the geostrophic component. This introduces the ambiguity of which spatial scale to choose. Here, we build upon the recent developments in internal tide (IT) corrections (Yadidya et al., 2025) and apply a dynamic mode decomposition (DMD)-based method introduced by Lapo et al. (2025) to robustly extract the geostrophic component associated with sub-inertial frequencies from the SWOT one-day-repeat orbit; we distribute the global dataset as a public good. We provide the joint probability density function (PDF) of vorticity and strain, and spectra of SSHa at a few cross-over regions.
title A strictly geostrophic product of sea-surface velocities from the SWOT fast-sampling phase
topic Atmospheric and Oceanic Physics
Data Analysis, Statistics and Probability
url https://arxiv.org/abs/2601.18182