Towards mapping total currents and winds during the BioSWOT-Med campaign with the OSCAR airborne instrument

The BioSWOT-Med cruise focused on the Western Mediterranean Sea, known for its rich plankton biodiversity under oligotrophic and moderate energy conditions. The cruise aimed to investigate the role of fine-scale circulation as a driver of plankton diversity, coinciding with the SWOT satellite's daily "fast-sampling" orbit over the same region. SWOT, with its high-resolution 2D observations of sea surface height at 15-120km spatial scale, offered a unique perspective on ocean dynamics.
Mesoscale and submesoscale currents play a crucial role in ocean-atmosphere interaction and marine biosphere processes. The SeaSTAR satellite mission concept (former ESA Earth Explorer 11 candidate at phase 0), is designed to observe small-scale ocean surface dynamics with a remarkable 1 km resolution, contributing to our understanding of carbon, water, energy, gases, and nutrient exchanges across various Earth systems.
To prepare for the SeaSTAR mission, the OSCAR (Ocean Surface Current Airborne Radar) airborne instrument was developed, providing a synoptic 2D view of ocean and atmosphere dynamics, including currents, waves, and winds, at fine scale. During the SEASTARex campaign in May 2022 over the Iroise Sea in Brittany, France, OSCAR demonstrated excellent performance against various measurements, including marine radar, ADCP, and HF radar.
Building on OSCAR's success, a campaign was organized in May 2023, coinciding with the Bio-SWOT campaign, to fly together with SWOT over a non-tidal dominated area, mapping small-scale dynamics. Satellite SAR images from various sources, including RCM, TerraSAR-X, Sentinel-1, RadarSat-2, and PAZ SAR, were collected for comparative analysis with OSCAR and SWOT data.
Initial comparisons between OSCAR and satellite data, spanning remote sensing instruments like SWOT, SAR imagers, and optical sensors, showed a high level of agreement. SWOT data, analyzed with a diverse dataset, promises to enhance understanding and characterization of dynamics observed in the new 2D images.
OSCAR's Doppler and scatterometry capabilities offer a fresh perspective on dynamic processes, particularly at fine scales, bridging the gap between in-situ point measurements and space-based sensors. The ongoing synergy between OSCAR and satellite data holds potential to advance our understanding of oceanic and atmospheric phenomena, addressing critical challenges related to climate, weather, and marine ecosystems.