For the first time, high-resolution surface current data from high-frequency radar have been obtained along the central and southern coasts of Vietnam, and combined with a modelling approach, this is helping scientists to understand coastal processes. The research showed that the surface circulation is driven not only by winds, but also by other factors. This can enrich public knowledge of the coastal dynamics that govern other environmental impacts along the coasts.

Suspended particulate matter (SPM) concentrations in estuaries have been observed to vary strongly over the spring–neap cycle. A systematic framework for analysing the processes causing this SPM variability is missing. In this study we set up such a framework. It is demonstrated using two model cases: an idealised test case and one representative of the Loire estuary. Using this, we explain the locations and timing of maximum concentrations in terms of the governing physical mechanisms.

We use a high-resolution atmosphere–ocean model to project Adriatic Dense Water dynamics under extreme warming. We find that a 15 % increase in sea surface evaporation will offset a 25 % decrease in extreme windstorms. As a result, future dense water will form at the same rate as today but will be too light to reach the Adriatic's deepest parts, making deep-water presence reliant on exchanges with the Ionian Sea.

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.

Novel hydrodynamic observations 40 m from an offshore wind turbine monopile show that the turbulent tidal lee wake doubles the drag acting on the seabed, potentially enhancing sediment transport and impacting the seabed habitat and the organisms that utilise it. It also enhances the vertical mixing of the water column, which drives the transport of heat, nutrients and oxygen. As offshore wind farms rapidly expand into deeper waters, array-scale wakes may have significant ecological impacts.

This study investigates the Agulhas Leakage and examines its role in the global ocean circulation. It utilises a high-resolution Earth system model and a preindustrial climate to look at the response of the Agulhas Leakage to the wind field and the Atlantic Meridional Overturning Circulation (AMOC) and its evolution under climate change. The Agulhas Leakage could influence the stability of the AMOC, whose possible collapse would impact the climate in the Northern Hemisphere.

This study shows AI can speed up data assimilation in ocean models. Researchers used convolutional neural networks (CNNs) to assimilate sea surface temperature and height observations in the Gulf of Mexico, learning to replicate corrections made by traditional, computationally expensive methods. CNN design and training window size significantly impacted accuracy, but the percentage of ocean pixels did not. These findings suggest CNNs may accelerate data assimilation in realistic settings.

We take advantage of the availability of several algorithms for most of the terms/corrections used to calculate altimetry sea level data to quantify and analyze the sources of uncertainty associated with the approach to the coast. The results highlight their hierarchy. Tidal corrections and mean sea surface height contribute to coastal sea level data uncertainties. Improving the retracking algorithm is today the main factor to bring accurate altimetry sea level data closer to the shore.

Mesoscale eddies are ubiquitous rotating currents in the ocean. Some eddies, called "materially coherent", are able to transport a different water mass from the surrounding water. By analyzing 3D eddy structures sampled during oceanographic cruises, we found that eddies can be nonmaterially coherent, accounting only for their surface properties, but materially coherent considering their properties at depth. Future studies cannot rely solely on satellite data to evaluate heat and salt transport.

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.

Ocean surface currents are routinely derived from satellite observations of the sea level, allowing regional- to global-scale synoptic monitoring. In order to overcome the theoretical and instrumental limits of this methodology, we exploit the synergy of multi-sensor satellite observations. We rely on deep learning, physics-informed algorithms to predict ocean currents from sea surface height and sea surface temperature observations. Results are validated by means of in situ measurements. 

Simulating the transport of floating particles on the ocean surface is crucial for solving many societal issues. Here, we investigate how the representation of wind-generated surface waves impacts particle transport simulations. We find that different wave-driven processes can alter transport patterns and that commonly adopted approximations are not always adequate. This suggests that ideally coupled ocean–wave models should be used for surface particle transport simulations.

This study uses drifters – instruments that follow surface ocean currents – to investigate the pathways of Arctic origin waters that enter the North Atlantic west of Greenland. It shows that these waters remain close to the coast as they flow over the Labrador shelf and only spread into the open ocean south of the Labrador Sea. These results contribute to better understanding how the North Atlantic will be affected by additional freshwater from Greenland and the Arctic in the coming decades.

We study salinity in estuaries consisting of a network of channels. To this end, we develop a model that computes the flow and salinity in such systems. We use the model to quantify the mechanisms by which salt is transported into estuarine networks, the response to changes in river discharge, and the impact of depth changes. Results show that when changing the depth of channels, the effects on salt intrusion into other channels in the network can be larger than the effect on the channel itself.

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.

Sea level observations along the swaths of the new SWOT (Surface Water and Ocean Topography) mission were used to characterize internal tides at three semidiurnal frequencies off the Amazon shelf in the tropical Atlantic during the SWOT calibration/validation period. The atlases were derived using harmonic analysis and principal component analysis. The SWOT-derived internal tide atlas outperforms the reference atlas previously used to correct SWOT observations.

This study proposes a novel cross-validation method to assess the instrumental stability in sea level trends. The method involves implementing a second tandem flight phase between two successive altimeter missions a few years after the first phase. The trend in systematic instrumental differences made during the two tandem phases can be estimated below ± 0.1 mm yr^-1 (16–84 % confidence level) on a global scale for time intervals between the tandem phases of 4 years or more.

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.

Concave coasts act as funnels, concentrating storm waters and leading to higher storm surges (SSs); convex coasts redistribute waters, reducing surges. We use the ADCIRC model to simulate peak surges (PSs) for different cyclone tracks, showing how coastline geometry, landfall location, and cyclone angle influence PSs. Cyclones passing near concave coasts without landfall can still cause high SSs, highlighting vulnerability in these regions. This insight aids in assessing coastal flood risks.

Lagrangian coherent structures (LCSs) describe material transport in ocean flow by describing transport and accumulation regions. We discuss the implications of model flow field uncertainty for finite-time Lyapunov exponents (FTLEs), which under certain conditions approximate LCSs. FTLEs add value to forecasting when they are certain and long-lived. Averaging FTLEs reveals where they are more certain and long-lived, often influenced by bottom topography.

Ship-based observations provide data of seawater properties like temperature, salinity, nutrients, and various gases, but some important world oceans have still not been covered. A voyage in 2019/20 in the southwest Indian Ocean along approximately 55° E from 30° S to Antarctica attempted to fill one such data-sparse region. The measured cross section of the Antarctic Circumpolar Current and accompanying eddies demonstrates various oceanic behaviours including fronts and eddy mixing.

Computer models are often used to estimate the ocean's CO₂ uptake due to a lack of direct observations. Because such idealized models do not match precisely with the real world, we combine real-world observations of ocean temperature and salinity with a model and study the effect on the modeled air–sea CO₂ flux (2010–2020). The corrections of temperature and salinity have their largest effect on regional CO₂ fluxes in the Southern Ocean in winter and a small effect on the global CO₂ uptake.

A comprehensive sand transfer model is proposed to study sediment dynamics in the lower reaches of the Changhua River on the island of Hainan. It captures the complex relationship between wave action, ocean currents, and sediment transport. Validated on the basis of on-site measurements, the model reveals significant sediment deposits which are significantly affected by coastal ocean currents and geological structures.

We explore how a semi-enclosed bay in the Humboldt Current System responds to the passage of extratropical cyclones. Using ERA5 data and acoustic Doppler current profiler observations, we found that intense north winds associated with these cyclones drive surface water into the gulf, creating pressure gradients that alter coastal currents, and may reduce residence times. This enhances our understanding of wind-driven coastal dynamics, impacting marine ecosystems and coastal management globally.