Overview

The Level-3 (L3) products are formally part of the Science Team Project DESMOS and funded by the French Early Adopter Program (i.e. PIA). Those products are lightweight, simple, and usable out-of-the-box; moreover, Nadir altimeter & KaRIn measurements are displayed in one single image.

The Value-added compared to SWOT L2 KaRIn (L2_LR_SSH) products are:

• State of the art research-grade upgrades (incl. very recent & submitted papers)

• Multi-mission calibration (SWOT is consistent with other altimeters)

• Noise-mitigation for SSHA derivatives (experimental, AI-based)

• Pre-made sophisticated editing procedure KaRIn and nadir instruments blended into a single image

• L3 has new layers (optional) that can blend with L2 fields

Example of SSHA (after noise reduction) (left), geostrophic velocities (middle) and relative vorticity (right) obtained with SWOT measurements contained in the SWOT L3 KaRIn ocean product

4 types of files are distributed: Basic, Expert, Technical and Unsmoothed

• Basic L3_LR_SSH includes only SSHA (Sea Surface Height Anomaly) and mean dynamic topography (MDT) on the 2km KaRIn grid

• Expert L3_LR_SSH includes the backscatter coefficient (sigma0), the mean sea surface (MSS) and geostrophic currents (absolute and anomalies) in addition to SSHA and mean dynamic topography (MDT). It also integrates algorithms, corrections and external models as separate layers. It is available on the 2km KaRIn grid

• Technical L3_LR includes additional parameters and geophysical fields that may be of interest for certain applications or that provides an alternative solution to those used in the core (Basic/Expert) datasets. It is available on the 2 km KaRIn grid

• Unsmoothed L3_LR_SSH includes the MSS, MDT and geostrophic currents (absolute and anomalies) in addition to the SSHA and MDT on the 250-m KaRIn native grid. Like the Expert subproduct, it also integrates a quality flag, corrections and external models as separate layers

Note

The Expert dataset includes all the Basic dataset content

Releases

Version	Dataset	Release date
V3.0	Expert	November 2025
	Technical	December 2025
V2.0.1	Expert	March 2025
	Unsmoothed
V2.0.0	Expert	27th January 2025
V1.0.2	Unsmoothed	18th October 2024
	Expert	17th September 2024
V1.0.1	Unsmoothed	28th June 2024
V1.0	Unsmoothed	14th June 2024
	Expert	3rd June 2024 (daily) 13th May 2024
V0.3	Expert	9th January 2024

Temporal coverage

The following table shows the temporal coverage of the L3_LR_SSH products. Coverage may differ between the Expert and Unsmoothed datasets. Some holes in the time series are due to missing L2_LR_SSH data or constraints on the Level-3 production. See the associated version notes for more details.

V3.0.0V2.0.1V2.0V1.0.2V1.0.1V1.0V0.3

	Basic/Expert/Technical
CalVal phase (1-day)	C474/T003 - C578/T004 28th March 2023 – 10th July 2023
Science phase (21-days)	C001/T149 - now 26th July 2023 – now

Data policy and condition of use

The SWOT L3 KaRIn ocean product is available free of charge for scientific studies and commercial activities.

How to cite

Publications should include the following statement in the Acknowledgments

Citation Basic L3_LR_SSH

“The SWOT_L3_LR_SSH product, derived from the L2 SWOT KaRIn Low rate ocean data products (L2_LR_SSH) (NASA/JPL and CNES), is produced and made freely available by AVISO and DUACS teams as part of the DESMOS Science Team project”. AVISO/DUACS., 2023. SWOT Level-3 SSH Basic (v3.0) [Data set]. CNES. https://doi.org/10.24400/527896/A01-2023.017

Citation Expert L3_LR_SSH

“The SWOT_L3_LR_SSH product, derived from the L2 SWOT KaRIn low rate ocean data products (L2_LR_SSH) (NASA/JPL and CNES), is produced and made freely available by AVISO and DUACS teams as part of the DESMOS Science Team project”. AVISO/DUACS, 2023. SWOT Level-3 SSH Expert (v3.0) [Data set]. CNES. https://doi.org/10.24400/527896/A01-2023.018

Citation Technical L3_LR_SSH

“The SWOT_L3_LR_SSH product, derived from the L2 SWOT KaRIn low rate ocean data products (L2_LR_SSH) (NASA/JPL and CNES), is produced and made freely available by AVISO and DUACS teams as part of the DESMOS Science Team project”. AVISO/DUACS, 2023. SWOT Level-3 SSH Technical (v3.0) [Data set]. CNES. https://doi.org/10.24400/527896/A01-2025.009

Citation Unsmoothed L3_LR_SSH

“The SWOT_L3_LR_SSH product, derived from the L2 SWOT KaRIn low rate ocean data products (NASA/JPL and CNES), is produced and made freely available by AVISO and DUACS teams as part of the DESMOS Science Team project”. AVISO/DUACS, 2024. SWOT Level-3 KaRIn Low Rate SSH Unsmoothed (v2.0.1) [Data set]. CNES. https://doi.org/10.24400/527896/A01-2024.003

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