Abstract's details
SWOT to study coastal dynamics: the case of North Current intrusions in the Northwestern Mediterranean Sea
Event: 2025 SWOT Science Team Meeting
Session: Deltas, Estuaries and Coasts
Presentation type: Oral
The monitoring of ocean currents is a key component in many coastal applications, ranging from biogeochemical resources to marine pollution or search and rescue. During the last three decades, satellite altimetry has played an essential role in the understanding and monitoring of ocean currents at global scale. However, its use is still limited in coastal areas due to both the lower data quality in this environment and the spatiotemporal data resolution, which is not suited to the short scales of coastal dynamics. The importance of ageostrophic currents in coastal regions also raises some limitations of the altimetry measurements.
Nonetheless, many recent studies addressing the different issues related to the derivation and exploitation of altimeter-derived coastal current velocities have shown that they efficiently complement coastal velocity fields retrieved from in-situ data (e.g., hydrographic observations, surface drifter, and moored or ship-based acoustic Doppler velocities) or from shore‐based HF radars. Indeed, one of the major advantages of this measurement technique is to provide long time series (i.e., more than 30 years) of spatially and temporally homogeneous information about the circulation, and to be available at near-global scale. The coastal altimetry data quality problem can be partially overcome thanks to dedicated processing with adequate corrections. Merging data from multiple missions has shown to improve the spatial and temporal resolutions. Finally, altimetry-derived geostrophic currents remain a substantial contribution to coastal circulation systems.
The SWOT mission represents the beginning of a new class of satellite altimeters, providing for the first time highly accurate 2D information at unrivalled resolution. In this study, we analyze and quantify the ability of SWOT to observe highly-dynamic coastal features associated with the North Current (a slope current located in the Northwestern Mediterranean Sea) during the Fast-Sampling Phase. We focus on particular events: the coastal intrusions of the current on the Gulf of Lion continental shelf. Through comparisons with in situ velocity measurements at the JULIO (Judicious Location for Intrusion Observation) station, and with outputs from a numerical simulation in the area, we show that SWOT-Karin provides unprecedented 2D current observations of such processes in the coastal strip.
Back to the list of abstractNonetheless, many recent studies addressing the different issues related to the derivation and exploitation of altimeter-derived coastal current velocities have shown that they efficiently complement coastal velocity fields retrieved from in-situ data (e.g., hydrographic observations, surface drifter, and moored or ship-based acoustic Doppler velocities) or from shore‐based HF radars. Indeed, one of the major advantages of this measurement technique is to provide long time series (i.e., more than 30 years) of spatially and temporally homogeneous information about the circulation, and to be available at near-global scale. The coastal altimetry data quality problem can be partially overcome thanks to dedicated processing with adequate corrections. Merging data from multiple missions has shown to improve the spatial and temporal resolutions. Finally, altimetry-derived geostrophic currents remain a substantial contribution to coastal circulation systems.
The SWOT mission represents the beginning of a new class of satellite altimeters, providing for the first time highly accurate 2D information at unrivalled resolution. In this study, we analyze and quantify the ability of SWOT to observe highly-dynamic coastal features associated with the North Current (a slope current located in the Northwestern Mediterranean Sea) during the Fast-Sampling Phase. We focus on particular events: the coastal intrusions of the current on the Gulf of Lion continental shelf. Through comparisons with in situ velocity measurements at the JULIO (Judicious Location for Intrusion Observation) station, and with outputs from a numerical simulation in the area, we show that SWOT-Karin provides unprecedented 2D current observations of such processes in the coastal strip.