SWOT enhances small-scale intrathermocline eddy detection

The paper “SWOT and multi-platform observations enhance small-scale intrathermocline eddy detection” by Verger-Miralles et al. of the FaSt-SWOT team was submitted to Geophysical Research Letters. Here the key points from the research.

Figure 2 from Verger-Miralles et al. (submitted): (A) SST, (B) SWOT SSHA, and (C) DUACS SSHA maps of the anticyclonic eddy on April 26, 2023. The trajectories of 5 SVP-B drifters deployed during the experiment (April 26-29,2023) are shown with thin black lines, and the trajectory of a previously deployed SVP-B drifter is represented by a thick black line (April 23-29, 2023). Pink dots indicate the end of each drifter’s trajectory.

Ocean currents with spatial scales between 1 and 100 km are essential for regulating Earth’s climate by distributing heat, nutrients, and other properties within the oceans. The Surface Water and Ocean Topography (SWOT) satellite mission, launched in December 2022, offers a unique contribution to retrieve small-scale upper ocean dynamics, as it measures ocean surface heights at a resolution ten times finer than previous satellites. During its initial calibration phase, the FaSt-SWOT team conducted a multi-platform field experiment to evaluate the capability of SWOT to detect and measure a small subsurface (or intrathermocline) eddy in the Western Mediterranean Sea. The SWOT satellite successfully captured the sea level and ocean currents related to this eddy, showing significant accuracy improvements over traditional satellites compared to different in-situ instruments: a 33% better representation of sea level and an improvement in the magnitude of horizontal velocities between 44 and 61%. These results demonstrate SWOT’s capability to observe small-scale ocean dynamics.

Key Points:

The fast-sampling phase of the new SWOT satellite altimetry mission provides a unique opportunity to monitor small-scale ocean processes

SWOT accurately detects the signal of a ~20-25 km-radius intrathermocline eddy, as observed by multi-platform in-situ measurements

SWOT improves sea surface height estimation by ~30% and horizontal velocities by up to 61% compared to conventional altimetry

Read the full preprint:

Verger-Miralles, E., et al. SWOT and multi-platform observations enhance small-scale intrathermocline eddy detection. Submitted to Geophysical Research Letters. Preprint available at: https://essopenarchive.org/users/863652/articles/1245399-swot-enhances-small-scale-intrathermocline-eddy-detection. DOI: 10.22541/essoar.173315547.75973902/v1

Note: Preprints have not been peer reviewed. Data may be preliminary.