Present-day sea level rise is not uniform regionally. For better understanding of regional sea level variations, a classical approach is to compare the observed sea level trend patterns with those of the sum of the contributions. If the regional sea level budget is not closed, this allows to detect errors in the observing systems. Our study based on this approach shows the the budget is not closed in the North Atlantic Ocean and identifies as main suspect, errors in Argo-based salinity data.

The surface mixed layer depth (MLD), where ocean properties are uniform, is key to ocean-atmosphere interactions and ocean dynamics. We propose an energy-based method that defines the MLD using a constant value of buoyancy work that accurately captures the upper ocean's well-mixed layer. This approach is globally and temporally consistent and reliable, improving MLD estimates, aiding ocean model validation, and advancing studies of ocean heat content and vertical exchanges.

We show that forcing-dependent presence of submesoscale processes is detected by glider observations and high-resolution numerical simulation. Peak of submesoscale variations was observed at the base of the upper mixed layer in spring and in the thermocline in summer. Coastal upwellings and topography-related instabilities of frontal currents were the likely drivers of submesoscale processes and subduction that transport surface waters and tracers below the thermocline.

Flooding caused by storm surges in the Adriatic Sea has become increasingly frequent. To better understand this trend, we compiled a catalogue that documents 27 major floods and gives an analysis of each event with respect to governing processes and coastal impacts. The analysis is based on ERA5 data and hourly sea levels recorded at Croatia’s oldest tide-gauge station Bakar, in the period between 1929 and 2022.

The Mediterranean faces more frequent and intense Marine Heatwaves, harming ecosystems and fisheries. Using Machine Learning, we developed a model to forecast these events up to seven days in the future, outperforming traditional methods. This approach enables faster, accurate forecasts, helping authorities mitigate impacts and protect marine resources.

This work combines hyperspectral sensors and unmanned aerial vehicles to detect and differentiate microalgal species from optical data on Patagonia fjords at local scale. The results show differences between in situ hyperspectral signals, especially at blue, green, and red to near-infrared spectra, distinguishing between diatoms and dinoflagellates species. These tools are mainly useful in coastal areas where the cloudiness and geographic heterogeneity make satellite data acquisition difficult.

Estimating Particulate Organic Carbon (POC) relies on proxies like the particulate backscattering coefficient (b_bp) derived from BioGeoChemical-Argo (BGC-Argo) floats and satellite data. BGC-Argo floats provide global insights into vertical bio-optical dynamics. This study integrates Sentinel-3 data and machine learning approaches to improve b_bp estimates in the top 250 meters of the water column. Results are promising in stable global oceanic areas but less consistent in more dynamic regions.

This study presents the annual and monthly MIOST (MIOST24) internal tide atlases for the Indo-Philippine archipelago and the region off the Amazon shelf. Derived from 25 years of altimetry data and an updated wavelength database, the atlases reveal significant monthly variability of internal tides in both regions. The new atlas improves the correction of internal tides in altimetry data and outperforms MIOST 2022 and HRET existing atlases, thus supporting the development of a global atlas.

Typhoons struck the northern coast of Kyushu Island, which faces the Tsushima Strait, the sea level rises approximately half a day after the typhoon passed. We elucidated mechanisms behind this event in the strait. Results showed that two types of seiches were triggered by potential energy release after the typhoon's passage. This study demonstrates that storm surges can occur even after a typhoon has passed and enhances understanding of storm surge characteristics in straits.

The mechanism analysis shows that the amplitude of near-inertial oscillations was modulated by the shoaling depth of the mix-layer induced by the inclined front, and trapped in the upper layer.

Our study provides a comprehensive assessment of microzooplankton ciliate trait structure, focusing on size spectrum, biodiversity, and biotic-abiotic interplay based on 175 stations (1117 samples) across five temperature zones, which offered an ideal paradigm for study the plankton response to future climate change. The study is full fill the scope of the Ocean Science in the ocean's physical, biogeochemical and biological and ecosystem properties and processes.

During the annual phytoplankton bloom, rates of primary production and carbon export in the Ross Sea, Antarctica are uncoupled from each other and from oxygen and carbon stocks. These biogeochemical rates support the high productivity, low export classification of the region and suggest that environmental factors influence these stocks and rates differently and make projections under future climate change scenarios difficult.

This research explores how ocean currents and wind influence the movement of floating materials, such as marine litter, in the Canary Current System. Using surface drifters, we tested different factors, including wind and wave effects, to improve the accuracy of simulations. Our findings reveal that wind and wave forces are crucial for predicting how floating debris travels. This work helps refine models for tracking marine pollution, aiding in better environmental management and cleaner oceans.

Subantarctic mode water in the South Pacific Ocean is important due to its role in the uptake and transport of anthropogenic heat and carbon. The Subantarctic mode water region can be split into two pools using mixed layer depth properties. Sensitivity experiments are used to understand the effects of heating and wind on each pool. It is found that the optimal conditions to form large amounts of Subantarctic mode water in the South Pacific are local cooling and upstream warming combined.

During the summer of 2022 in the eastern Gulf of Lion (NW Mediterranean), exceptionally warm temperatures were observed down to depths of 30 m, along with massive mortality of benthic species. It has been shown that these deep marine heatwaves are linked to south-easterly wind episodes, which induce deep plunges of surface water overheated by the atmospheric heatwave. These events are rare in summer, but their impact on ecosystems is dramatic and will only increase with climate change.

The Southern Ocean Time Series program acquires observations in Subantarctic waters south of Australia. We present the seasonality in hydrography, biogeochemistry, phytoplankton community composition and biodiversity, and carbon export to the deep-sea using observations collected between 1997 and 2022. We also review recent research underpinned by these observations and emphasise the value of long time series for understanding ocean processes and responses to a changing climate.

We analyze the geostrophic circulation and tidal effects in the Gulf of Gabès from 30 years of altimetry data (1993–2022) and the outputs of a high resolution ocean model for the year 2022.

Marine heatwaves are of growing concern around the world. We use a state of the art ensemble of downscaled climate models to project how often heatwaves will occur in future across northwest Europe under a high-emissions scenario. The projections show that without emissions reductions, heatwaves will occur more than half of the time in future. We show that the seafloor is expected to experience much more frequent heatwaves than the sea surface in future.

Here, we develop and run a high resolution ocean model of Jones Sound from 2003–2016 and characterize circulation into, out of, and within the sound as well as associated sea ice and productivity cycles. Atmospheric and ocean warming drive sea ice decline, which enhance biological productivity due to the increased light availability. These results highlight the utility of high resolution models in simulating complex waterways and the need for sustained oceanographic measurements in the sound.

Particulate organic carbon plays a vital role in the ocean carbon cycle, yet its transformation involves complex processes that are not fully understood. This study examines the vertical distribution the stable carbon isotopes in the tropical Northwestern Pacific, identifying three distinct biogeochemical layers of POC transformation, which contribute to a deeper understanding of the ocean carbon cycle.

This study investigates the synoptic weather patterns that cause extreme, high-frequency sea level oscillations in the Adriatic Sea. Using synoptic data from ERA5 reanalysis with 17 years of tide gauge data and advanced clustering techniques, we identify distinct weather patterns linked to these events, some of which have been unknow. These insights improve understanding of sea level variability and have potential applications in forecasting coastal hazards.

We evaluated a deep-learning model, HIDRA2, for predicting sea levels along the Estonian coast and compared it to traditional numerical models. HIDRA2 performed better overall, offering faster forecasts and valuable uncertainty estimates using ensemble predictions.

Using measurements and computer models, we identify a large flux of oxygen within the Southwest Monsoon Current, which flows north into the Bay of Bengal between June and September each year. Oxygen levels in the Bay are very low, but not quite low enough for key nutrient cycles to be as dramatically altered as in other low-oxygen regions. We suggest that the flux we identify contributes to keeping oxygen levels in the Bay above the threshold below which dramatic changes would occur.

This study examines how waves and ocean currents interact during severe weather, focusing on Medicane Ianos, one of the strongest storms in the Mediterranean. Using advanced modeling, we created a unique system to simulate these interactions, capturing effects like changes in water levels and wind impact on waves. We validated our approach with ideal tests and real data from the storm.

Turbulent water motions are important for the exchange of momentum, heat, nutrients, and suspended matter in the deep-sea. The shape of marine topography influences most water turbulence via breaking internal waves at ‘critically’ sloping seafloors. In this paper, the concept of critical slopes is revisited from a global internal wave-turbulence viewpoint using seafloor topography- and moored temperature sensor data. Potential robustness of the seafloor-internal wave interaction is discussed.

The Atlantic Meridional Overturning Circulation (AMOC) is a major part of the ocean circulation. Satellite gravimetry missions, like GRACE, which measure changes in Earth's mass distribution, could help monitor changes in the AMOC by detecting variations in ocean bottom pressure. To help asses if future satellite missions could detect these changes, we use ocean model simulation data to assess their connection. Additionally, we create a synthetic dataset future satellite mission simulations.

Surface waves are generated by the wind and wave measurements can also be used to estimate the wind speed. This is beneficial in the open ocean where direct measurements of the wind are difficult. The wind speed deduced from wave measurements serve as a third estimate of the wind speed in addition to satellite measurements or numerical model results. We implemented such and algorithm to be used with wave data from a small buoy and validated it against direct wind measurements and model results.

A modern climate model is used to test the hypothesis that changes observed during El Niños are, in part, forced by changes in the temperature of the North Equatorial Counter Current. This is a warm current that flows eastwards across the Pacific, a few degrees north of the Equator, close to the Inter-Tropical Convection Zone, a major region of deep atmospheric convection. The tests generate a significant El Niño type response in the ocean, giving confidence that the hypothesis is correct.

We identify the Mexican Coastal Current interaction with coastline using sea level anomaly and derived geostrophic velocities, finding that an average width of 95 km and an average speed of 0.3 m/s width seasonal variability. Numerical modeling proves that interaction of coastal current with the coastline generates ocean eddies in some places that form a wide concavity. These eddies are formed while the current is present getting intense and detaching from the coast until the current weakens.