Antoine Delepoulle

This study introduces the new global Mesoscale Eddy Trajectory Atlases, META4.0 available in an AVISO repository at https://doi.org/10.24400/527896/a01-2026.001 (CLS and CNES, 2026). META4.0 provides eddy detections, trajectories, and interaction networks derived from satellite altimetry. Eddy detection relies on the pyeddytracker (PET) algorithm (Mason et al., 2014), further optimized by Pegliasco et al. (2022), and represents a substantial improvement over the previous META3.2 product (SSALTO/DUACS, distributed by AVISO+ with CNES support). The main advance of META4.0 is the explicit identification of eddy merging and splitting events. By combining grouping, which links detections across consecutive days, and segmentation, which tracks continuity through interaction events, trajectories are organized into networks of interconnected eddies. This network-based representation complements the single-trajectory view of eddy life cycles by explicitly accounting for eddy interactions. The paper presents both diagnostic tools designed to explore individual eddy networks (e.g., timelines, spatial trajectories, and eddy properties such as effective radius or shape error) and the results of a global statistical analysis over more than three decades. These tools and analyses offer new diagnostics for investigating network properties, eddy lifetimes, and the spatial and temporal distribution of merging and splitting events of the META4.0 atlas. Clustering analyses reveal recurrent interaction patterns and identify regions where eddy networks are particularly active. An independent dataset of surface chlorophyll concentration is used for qualitative validation of selected events. Finally, Lagrangian advection of synthetic particles highlights coherent forward and backward transport signatures associated with interaction events, providing a physical validation of the reconstructed networks. Overall, META4.0 offers a novel and physically consistent framework to characterize mesoscale eddy interactions and to better understand their role in shaping ocean dynamics.

This study introduces the new global Mesoscale Eddy Trajectory Atlases (META4.0), which provide eddy detections, trajectories, and interaction networks derived from satellite altimetry. Eddy detection relies on the pyeddytracker (PET) algorithm (Mason et al., 2014), further optimized by Pegliasco et al. (2022), and represents a substantial improvement over the previous META3.2 product (SSALTO/DUACS, distributed by AVISO+ with CNES support). The main advance of META4.0 is the explicit identification of eddy merging and splitting events. By combining grouping, which links detections across consecutive days, and segmentation, which tracks continuity through interaction events, trajectories are organized into networks of interconnected eddies. This network-based representation complements the classical single-trajectory view of eddy life cycles by explicitly accounting for eddy interactions. The paper presents both diagnostic tools designed to explore individual eddy networks (e.g., timelines, spatial trajectories, and eddy properties such as effective radius or shape error) and the results of a global statistical analysis over more than three decades. These analyses provide new insights into network properties, eddy lifetimes, and the spatial and temporal distribution of merging and splitting events. Clustering analyses reveal recurrent interaction patterns and identify regions where eddy networks are particularly active. Independent datasets, including sea surface temperature and chlorophyll concentration, are used for qualitative validation of selected events. Finally, Lagrangian advection of synthetic particles highlights coherent forward and backward transport signatures associated with interaction events, providing a physical validation of the reconstructed networks. Overall, META4.0 offers a novel and physically consistent framework to characterize mesoscale eddy interactions and to better understand their role in shaping ocean dynamics.

This study introduces the new global Mesoscale Eddy Trajectory Atlases (META4.0), which provide eddy detections, trajectories, and interaction networks derived from satellite altimetry. Eddy detection relies on the pyeddytracker (PET) algorithm (Mason et al., 2014), further optimized by Pegliasco et al. (2022), and represents a substantial improvement over the previous META3.2 product (SSALTO/DUACS, distributed by AVISO+ with CNES support). The main advance of META4.0 is the explicit identification of eddy merging and splitting events. By combining grouping, which links detections across consecutive days, and segmentation, which tracks continuity through interaction events, trajectories are organized into networks of interconnected eddies. This network-based representation complements the classical single-trajectory view of eddy life cycles by explicitly accounting for eddy interactions. The paper presents both diagnostic tools designed to explore individual eddy networks (e.g., timelines, spatial trajectories, and eddy properties such as effective radius or shape error) and the results of a global statistical analysis over more than three decades. These analyses provide new insights into network properties, eddy lifetimes, and the spatial and temporal distribution of merging and splitting events. Clustering analyses reveal recurrent interaction patterns and identify regions where eddy networks are particularly active. Independent datasets, including sea surface temperature and chlorophyll concentration, are used for qualitative validation of selected events. Finally, Lagrangian advection of synthetic particles highlights coherent forward and backward transport signatures associated with interaction events, providing a physical validation of the reconstructed networks. Overall, META4.0 offers a novel and physically consistent framework to characterize mesoscale eddy interactions and to better understand their role in shaping ocean dynamics.

This study introduces the new global Mesoscale Eddy Trajectory Atlases (META4.0), which provide eddy detections, trajectories, and interaction networks derived from satellite altimetry. Eddy detection relies on the pyeddytracker (PET) algorithm (Mason et al., 2014), further optimized by Pegliasco et al. (2022), and represents a substantial improvement over the previous META3.2 product (SSALTO/DUACS, distributed by AVISO+ with CNES support). The main advance of META4.0 is the explicit identification of eddy merging and splitting events. By combining grouping, which links detections across consecutive days, and segmentation, which tracks continuity through interaction events, trajectories are organized into networks of interconnected eddies. This network-based representation complements the classical single-trajectory view of eddy life cycles by explicitly accounting for eddy interactions. The paper presents both diagnostic tools designed to explore individual eddy networks (e.g., timelines, spatial trajectories, and eddy properties such as effective radius or shape error) and the results of a global statistical analysis over more than three decades. These analyses provide new insights into network properties, eddy lifetimes, and the spatial and temporal distribution of merging and splitting events. Clustering analyses reveal recurrent interaction patterns and identify regions where eddy networks are particularly active. Independent datasets, including sea surface temperature and chlorophyll concentration, are used for qualitative validation of selected events. Finally, Lagrangian advection of synthetic particles highlights coherent forward and backward transport signatures associated with interaction events, providing a physical validation of the reconstructed networks. Overall, META4.0 offers a novel and physically consistent framework to characterize mesoscale eddy interactions and to better understand their role in shaping ocean dynamics.

The DUACS system (Data Unification and Altimeter Combination System), developed as part of the CNES/SALP project, Copernicus Marine Service, and Copernicus Climate Change Service, provides high-quality multi-mission altimetry sea level products for oceanographic applications, climate forecasting centers, and the geophysics and biology communities. These products include user-friendly Level-3 (L3: along-track/swath cross-calibrated sea surface height anomalies [SSHA]) and Level-4 (L4: multi-sensor merged maps or time series) data.L3 algorithms originally designed for nadir altimeters have been extended to process SWOT swath altimeter data. Enhancements include state-of-the-art Level-2 corrections and models contributed by the research community, a data-driven and statistical approach to identifying and removing spurious or suspicious pixels, a multi-satellite calibration process leveraging the existing nadir altimeter constellation, and a noise-mitigation algorithm powered by a convolutional neural network. The L3 algorithms currently process both resolutions of the Level-2 LR product: 2 km and 250 m. These L3 products are freely accessible via the AVISO+ portal.This presentation aims to introduce the existing and upcoming L3 KaRIn products that can address coastal applications. Although currently based on LR measurements designed for open‑ocean use, L3 KaRIn products can also be relevant for certain coastal applications. The 250 m data processing enables observations close to the coastline; the availability of several variables allows users to adjust the physical content of the measurement; and a quality flag based on multiple criteria makes it possible to refine data selection. In addition, L3 products benefit from improved calibration that best corrects KaRIn systematic errors and ensures consistency across all altimetric missions. Finally, L3 products are regularly updated to incorporate state‑of‑the‑art processing methods and to adapt the products to users’ specific needs. Thus, a future line of L3 KaRIn products dedicated to coastal needs and possible based on upstream HR may be developed in 2026-2027.

This study introduces the new global Mesoscale Eddy Trajectory Atlases (META4.0), which provide eddy detections, trajectories, and interaction networks derived from satellite altimetry. Eddy detection relies on the pyeddytracker (PET) algorithm (Mason et al., 2014), further optimized by Pegliasco et al. (2022), and represents a substantial improvement over the previous META3.2 product (SSALTO/DUACS, distributed by AVISO+ with CNES support). The main advance of META4.0 is the explicit identification of eddy merging and splitting events. By combining grouping, which links detections across consecutive days, and segmentation, which tracks continuity through interaction events, trajectories are organized into networks of interconnected eddies. This network-based representation complements the classical single-trajectory view of eddy life cycles by explicitly accounting for eddy interactions. The paper presents both diagnostic tools designed to explore individual eddy networks (e.g., timelines, spatial trajectories, and eddy properties such as effective radius or shape error) and the results of a global statistical analysis over more than three decades. These analyses provide new insights into network properties, eddy lifetimes, and the spatial and temporal distribution of merging and splitting events. Clustering analyses reveal recurrent interaction patterns and identify regions where eddy networks are particularly active. Independent datasets, including sea surface temperature and chlorophyll concentration, are used for qualitative validation of selected events. Finally, Lagrangian advection of synthetic particles highlights coherent forward and backward transport signatures associated with interaction events, providing a physical validation of the reconstructed networks. Overall, META4.0 offers a novel and physically consistent framework to characterize mesoscale eddy interactions and to better understand their role in shaping ocean dynamics.

The NASA-CNES altimetry mission SWOT (Surface Water and Ocean Topography) deployed in December 2022 embarks a Ka-band Radar Interferometer (KaRIn), providing a 120 km-wide swath sea level measurement. On 19 May 2023, SWOT was able to record a 2D signature of the tsunami generated by the M_w 7.7 earthquake southeast of the Loyalty Islands (southwest Pacific Ocean), about 1 h after the earthquake, on a straight SSW-NNE path. Comparison between numerical models and real measurements was performed to assess SWOT's ability to monitor tsunami waves. A uniform coseismic slip rupture model allows to satisfactorily fit the regional observations. Testing models against a dynamic representation of the tsunami wavefield (instead of static) show a good phase agreement, but simulated amplitudes are lower than the measurements. However, this SWOT unprecedented 2D observation critically inform on tsunami propagation and modelling, and offer a breakthrough perspective for better predictions.

Off the Amazon shelf, internal solitary waves (ISWs) generated by internal tides interact with mesoscale eddies, leading to significant modifications in their propagation and structure. For the first time, these interactions are directly observed from repeated high-resolution satellite measurements, notably those provided by the newly launched SWOT (Surface Water and Ocean Topography) mission. The study investigates ISWs detection and the modifications in ISW's characteristics resulting from interactions with eddies across three contrasting scenarios: ISW propagation in the absence of mesoscale eddies, ISW refraction by a cyclonic eddy, and ISW diffraction by an anticyclonic eddy. ISW crests are extracted using a band-pass filtering approach, enabling precise tracking of essential geometric and dynamical features, including propagation direction, crest-to-crest spacing, and wavefront shape. Prior to any interaction with eddies, three mode-1 ISW packets propagate in a steady and coherent manner, exhibiting planar wavefronts and consistent direction, with Absolute Dynamic Topography (ADT) amplitudes ranging from 8 to 14 cm. The results highlight the diversity of ISW responses depending on eddy conditions. In the absence of eddies, interaction with a seamount induces energy transfer from mode-1 to mode-3 ISWswaves (13 crests detected), while propagation direction is maintained and the ADT signature weakens to below 8 cm. In the presence of a cyclonic eddy above the seamount, ISW trajectories are refracted westward by roughly 50 degrees (7 crests detected), with increased wavecrest curvature and intensification of mode-3 generation, while ADT amplitudes decrease below 6 cm. Conversely, near the western boundary of an anticyclonic eddy, ISWs split into two distinct pathways: a western branch is refracted with flatter wavefronts, reduced crest spacing, and ADT amplitudes below 0.2 cm (9 crests detected), while an eastern branch follows the eddy's edge, displaying enhanced curvature, recognizable surface signatures of wave packets, and ADT values exceeding 9 cm (6 crests detected). Together, these findings demonstrate the ability of SWOT-based monitoring to capture the complexity of ISW dynamics and provide new insight into their nonlinear response to interactions with mesoscale and submesoscale oceanic structures.

Off the Amazon shelf, mesoscale eddies interact with internal solitary waves (ISWs), modifying their characteristics. For the first time, such interactions are directly observed through repeated measurements from a set of high-resolution satellite data, including the recently launched SWOT (Surface Water and Ocean Topography) mission. This study investigates ISWs detectable in SWOT Absolute Dynamic Topography (ADT) and characterizes the changes in their properties induced by interactions with mesoscale eddies. The analysis focuses on three scenarios: ISW propagation in the absence of eddies, ISW refraction by a cyclonic eddy, and ISW diffraction by an anticyclonic eddy. ISW crests were identified and extracted using a band-pass filtering technique, allowing accurate tracking of key features such as propagation direction, spacing between individual crests, and wavecrest geometry. Before any interaction with eddies, mode-1 ISWs propagate steadily, with consistent direction and planar wavefronts. A key finding is the variety of ISW responses depending on eddy conditions. In the first case, in the absence of eddy, the interaction of ISWs with a seamount induced energy transfer from mode-1 to mode-3 ISWs, while the propagation direction remains unchanged. In the second case, a cyclonic eddy overlaying the seamount refracted ISW trajectories westward by approximately 50°, while also increasing wavecrest curvature and enhancing the generation of mode-3 waves. In the third case, at the western edge of an anticyclonic eddy near the seamount, the ISWs are split into two distinct paths: one branch refracted westward, exhibiting flatter wave crests and reduced spacing between them; the other branch followed the eastern edge of the eddy, displaying surface signatures of wave packets and enhanced wavecrest curvature. These results demonstrate the effectiveness of the proposed approach in capturing the complex dynamics of ISWs. They offer novel insights into the nonlinear behavior of ISWs and their interactions with mesoscale and submesoscale oceanic features.

Off the Amazon shelf, mesoscale eddies interact with internal solitary waves (ISWs), modifying their characteristics. For the first time, such interactions are directly observed through repeated measurements from a set of high-resolution satellite data, including the recently launched SWOT (Surface Water and Ocean Topography) mission. This study investigates ISWs detectable in SWOT Absolute Dynamic Topography (ADT) and characterizes the changes in their properties induced by interactions with mesoscale eddies. The analysis focuses on three scenarios: ISW propagation in the absence of eddies, ISW refraction by a cyclonic eddy, and ISW diffraction by an anticyclonic eddy. ISW crests were identified and extracted using a band-pass filtering technique, allowing accurate tracking of key features such as propagation direction, spacing between individual crests, and wavecrest geometry. Before any interaction with eddies, mode-1 ISWs propagate steadily, with consistent direction and planar wavefronts. A key finding is the variety of ISW responses depending on eddy conditions. In the first case, in the absence of eddy, the interaction of ISWs with a seamount induced energy transfer from mode-1 to mode-3 ISWs, while the propagation direction remains unchanged. In the second case, a cyclonic eddy overlaying the seamount refracted ISW trajectories westward by approximately 50°, while also increasing wavecrest curvature and enhancing the generation of mode-3 waves. In the third case, at the western edge of an anticyclonic eddy near the seamount, the ISWs are split into two distinct paths: one branch refracted westward, exhibiting flatter wave crests and reduced spacing between them; the other branch followed the eastern edge of the eddy, displaying surface signatures of wave packets and enhanced wavecrest curvature. These results demonstrate the effectiveness of the proposed approach in capturing the complex dynamics of ISWs. They offer novel insights into the nonlinear behavior of ISWs and their interactions with mesoscale and submesoscale oceanic features.