Decadal changes in phytoplankton functional composition in the Eastern English Channel: possible upcoming major effects of climate change Ocean Science DOI 10.5194/os-21-679-2025 24 March 2025 This study provides the first assessment of decadal changes in the whole phytoplankton community, addressed by flow cytometry, in the highly productive waters of the Strait of Dover. A significant surface seawater temperature increase of 1°C, associated with an important change in the nutrient concentration and balance, has triggered a change in the phytoplankton communities, characterized by a higher total abundance and an increasing proportion of the smallest cells (picroeukaryotes and picocyanobacteria). Read more
Turbulent heat flux dynamics along the Dotson and Getz ice-shelf fronts (Amundsen Sea, Antarctica) Ocean Science DOI 10.5194/os-21-359-2025 7 February 2025 Few observations exist in the Amundsen Sea. Consequently, studies rely on reanalysis (e.g., ERA5) to investigate how the atmosphere affects ocean variability (e.g., sea-ice formation and melt). We use data collected along ice shelves to show that cold, dry air blowing from Antarctica triggers large ocean heat loss, which is underestimated by ERA5. We then use an ocean model to show that this bias has an important impact on the ocean, with implications for sea-ice forecasts. Read more
Internal tides off the Amazon shelf in the western tropical Atlantic: analysis of SWOT Cal/Val mission data Ocean Science DOI 10.5194/os-21-325-2025 4 February 2025 This study focuses on the internal tides (ITs) off the Amazon shelf in the tropical Atlantic. It is based on 2 km horizontally gridded observations along the swaths of SWOT (Surface Water and Ocean Topography) track 20 during the calibration/validation phase (Cal/Val, 1 d orbit) from late March to early July 2023. We evaluate the amplitude of M2, N2, and S2 frequencies and use the M2 atlas as an internal tide correction model for SWOT observations. Internal tide amplitudes (models or atlases) are first derived by harmonic analysis of the SWOT sea level anomaly (SLA). The estimation is improved by performing a principal component analysis before the harmonic analysis. The results compare very well with the high-resolution empirical tide (HRET) internal tide model, the reference product for internal tide corrections in altimetry observations. The coherent mode 1 and mode 2 M2 can be distinguished in the internal tide model derived from SWOT, while the higher modes with their strong SLA signature are seen mostly in the incoherent part. In comparison to HRET, the correction of SWOT observations with SWOT-based atlases may be more relevant for this track. SWOT Cal/Val mission data">Read more
The alongshore tilt of mean dynamic topography and its implications for model validation and ocean monitoring Ocean Science DOI 10.5194/os-21-181-2025 31 January 2025 Mean dynamic topography (MDT) describes variations in the mean sea surface height above a reference surface called a geoid. We show that MDT predicted by a regional ocean model, including a significant tilt of several centimeters along the coast of Nova Scotia, is in good agreement with estimates based on sea level observations. We demonstrate that this alongshore tilt of MDT can provide a direct estimate of the average alongshore current and also of the area-integrated nearshore circulation. Read more
Blending 2D topography images from the Surface Water and Ocean Topography (SWOT) mission into the altimeter constellation with the Level-3 multi-mission Data Unification and Altimeter Combination System (DUACS) Ocean Science DOI 10.5194/os-21-283-2025 31 January 2025 The Surface Water and Ocean Topography (SWOT) mission delivers unprecedented swath-altimetry products. In this paper, we describe how we extended the Level-3 algorithms to handle SWOT’s unique swath-altimeter data. We also illustrate and discuss the benefits, relevance, and limitations of Level-3 swath-altimeter products for various research domains. SWOT) mission into the altimeter constellation with the Level-3 multi-mission Data Unification and Altimeter Combination System (DUACS)">Read more
Integrating wide-swath altimetry data into Level-4 multi-mission maps Ocean Science DOI 10.5194/os-21-63-2025 15 January 2025 The Surface Water and Ocean Topography (SWOT) mission provides unprecedented swath altimetry data. This study examines SWOT’s impact on mapping systems, showing a moderate effect with the current nadir altimetry constellation and a stronger impact with a reduced one. Integrating SWOT with dynamic mapping techniques improves the resolution of satellite-derived products, offering promising solutions for studying and monitoring sea-level variability at finer scales. Read more
Impact of Hurricane Irma on coral reef sediment redistribution at Looe Key Reef, Florida, USA Ocean Science DOI 10.5194/os-20-661-2024 26 June 2024 Global understanding of storm-driven sediment transport along coral reefs and its impact on species and habitats is limited. Measurement of seafloor elevation and volume change due to a category 4 hurricane showed rapid burial of coral reef habitats and migration of large seafloor features due to the storm. Post-storm erosion rates were 2 orders of magnitude greater than historical rates, indicating areas of seafloor instability that could be less suitable for restoration of benthic species. USA">Read more
Resemblance of the global depth distribution of internal-tide generation and cold-water coral occurrences Ocean Science DOI 10.5194/os-20-569-2024 8 May 2024 Cold-water corals (CWCs) and tidal waves in the interior of the ocean have been connected in case studies. We demonstrate this connection globally using hydrodynamic simulations and a CWC database. Internal-tide generation shows a similar depth pattern with slope steepness and latitude as CWCs. Our results suggest that internal-tide generation can be a useful predictor of CWC habitat and that current CWC habitats might change following climate-change-related shoaling of internal-tide generation. Read more
Constraining an eddy energy dissipation rate due to relative wind stress for use in energy budget-based eddy parameterisations Ocean Science DOI 10.5194/os-19-1669-2023 27 November 2023 The dissipation rate of eddy energy in current energy budget-based eddy parameterisations is still relatively unconstrained, leading to uncertainties in ocean transport and ocean heat uptake. Here, we derive a dissipation rate due to the interaction of surface winds and eddy currents, a process known to significantly damp ocean eddies. The dissipation rate is quantified using seasonal climatology and displays wide spatial variability, with some of the largest values found in the Southern Ocean. Read more
Southern Ocean warming and Antarctic ice shelf melting in conditions plausible by late 23rd century in a high-end scenario Ocean Science DOI 10.5194/os-19-1595-2023 17 November 2023 How much the Antarctic ice shelf basal melt rate can increase in response to global warming remains an open question. To achieve this, we compared an ocean simulation under present-day atmospheric condition to a one under late 23rd century atmospheric conditions. The ocean response to the perturbation includes a decrease in the production of cold dense water and an increased intrusion of warmer water onto the continental shelves. This induces a substantial increase in ice shelf basal melt rates. Read more
