Ocean forecasting systems predict ocean water level, but the accuracy of predictions varies as a function of the forecast lead time and the dynamics causing water level variability. This study investigates the accuracy of predictions of tidal water levels in the AMSEAS forecast system, with emphasis on the small (roughly 5 cm) fluctuations associated with the baroclinic tide. To be useful, data from future satellites will require accurate forecasts; their accuracy is quantified in this study.

A new methodology, named as IBR, is developed to estimate the response of the coastal ocean to meteorological forcing. The response is taken as the combination of the static response calculated using inverted barometer formula and the dynamic response estimated using multivariable linear regression. The analysed results in the Bohai Bay indicate that the adjusted sea levels are related more to the regional wind than to the local wind and the IBR is a feasible and relatively effective method.

Convection deeper than 1,300 m persisted in the Irminger Sea during four consecutive winters (2015–2018). The 2015 deep convection was favored by exceptional atmospheric forcing. The 2016–2018 deep convection, which occurred under averaged atmospheric forcing, was favored by the preconditioning of the water column thanks to the cooling of the layer 200–800 m and the freshening of the layer 1,200 m–1,400 m.

This work investigates the seasonal variations in the major tidal constituents in the Bohai Bay. The M₂ tidal amplitude and phase reach maximum in summer and minimum in winter, while the frequencies of the S₂ and K₁ tidal amplitudes and phases and the O₁ tidal phase are semi-annual. The results of numerical experiments indicate that the seasonality of stratification and vertical eddy viscosity coefficient induce seasonal variations in the major tidal phases and amplitudes, respectively.

Using simulated "signal" of Sea Surface Height Anomalies (SSHA) where the phase speed of the dominant mode is known a-priory, we demonstrate that four of the common methods employed in estimating the propagation speed of SSHA do not identify the correct input mode. This finding explains the lack of progress made in recent years in bridging the gap between the "too fast" Rossby wave phase speed observations by satellites and the phase speed in the highly accurate linear Trapped wave theory.

Diatoms are a group of phytoplankton species responsible for ~20% of primary production on Earth. Ocean acidification (OA) could influence diatoms but the key question is if they become more or less important within marine food webs. Here we synthesize OA experiments with natural communities and found: Diatoms are more likely to be positively than negatively affected by OA but there will be winners/losers within communities. This has important implications for the ecosystem services they provide

The FluxEngine is an open source software toolbox designed to allow the easy calculation of air-sea gas fluxes. This manuscript describes new functionality and capabilities, which include the ability to calculate fluxes for nitrous oxide and methane, optimisation for running FluxEngine on a stand-alone desktop computer, and extensive new features to support the in situ measurement community. Four research case studies are used to demonstrate these new features.

In order to provide an aid for the interpretation of observations of the formation, the structure and the dynamics of submesoscale patterns, a numerical model is applied in a double-offline nested setup to a subarea of the Baltic Sea. A model with 500-m horizontal resolution is nested into an existing operational model in order to create a realistic mesoscale environment. Turbulent patterns with horizontal scales < 1 km are resolved by a second nest with 100-m resolution.

This work presents high-resolution simulations of a coupled regional model in the Mediterranean basin. The used approach allows assessing the role of ocean feedbacks in the downscaled climate. Our results show good skills in simulating present climate; the model's robustness introduces improvements in reproducing physical processes at local scales. Our climate projections reveal that by the end of the 21st century the Mediterranean Sea will be warmer and saltier, although not in a homogeneous way.

The Galápagos Archipelago and Marine Reserve is among the world's most iconic wildlife refuges. Yet, plastic litter is now found even in this remote island archipelago. It is unclear where this plastic originates from. In this study, we show that remote coastal sources of plastic pollution are fairly localized and limited to South and Central American coastlines. Identifying how plastic ends up in the Galápagos aids integrated management opportunities to reduce plastic pollution.

The work presented is part of a bigger wave energy project on Swedish wave energy resource mapping. The project aims to generate and combine different layers of information for the Swedish Exclusive Economic Zone in order to identify the most suitable areas for wave energy conversion. This paper presents the results for the mean sea level variation layer. For the case study considered, the most suitable sites where to deploy WEC parks are found in the Gotland Basins and in the Bothnian Sea.

This study presents a detailed spatial structure and temporal variability of the deep circulation under enhanced mixing in the South China Sea (SCS) based on eddy-resolving model simulations verified by continuous current-meter observations and enables us to investigate sensitivity to distribution of mixing. Comparing the northern shelf of the SCS with the Luzon Strait, deep circulation in the SCS is more sensitive to the large vertical mixing parameters in the Zhongsha Island Chain area.

This work investigates the variabilities of the barrier layer thickness (BLT) in the tropical Indian Ocean with the Simple Ocean Data Assimilation version 3 ocean reanalysis data. Our results show that the seasonal variation of the BLT is in relation to the changes of thermocline and sea surface salinity. In terms of the interannual time scale, BLT presents a clear seasonal phase-locking dominated by different drivers during the Indian Dipole and El Niño South Oscillation events.

Methane seepage from the seafloor west of Svalbard was investigated with fast-response membrane inlet laser spectrometer. The acquired data was in good agreement with traditional sparse discrete water sampling, subsequent Gas Chromatography, and with a new 2D model, based on echosounder data. However, the acquired high-resolution data revealed unprecedented details of the methane distribution, which highlights the need for such methods, for future climate studies.

Extreme water levels are often created by several drivers with different properties. For example, the contribution from the water volume of the Baltic Sea follows a Gaussian distribution but storm surges represent a Poisson process. We show that wave set-up heights (the third major component of high water levels) frequently match an inverse Gaussian distribution. Therefore, high set-up events may occur more frequently than it could be expected from the probability of occurrence of severe seas.

In December 2002 and January 2003 satellite observations of Chlorophyll showed a wavelike pattern with a wavelength of about 750 km south west to the Cape Verde peninsula. Such a pattern suggests the existence of a locally generated Rossby wave which slowly propagated westward. To verify this hypothesis a numerical study based on a simple model has been conducted. The numerical results are completed by an analytical study which evaluates the potential impact of the coastline shape.

This work uses high-resolution global ocean model data to quantify the sinking of waters in the subpolar North Atlantic. The largest amount of sinking is found at the depth of maximum AMOC below the mixed layer depth, occurring mostly near the boundaries (90 %), in the first 300 km off the coast. However, the characteristics of the sinking (total amount, seasonal variability and vertical structure) varies largely according to the region considered, revealing a complex picture for sinking.

Waters form the Subtropical Water mass (SUW) generated in the central Atlantic enter the Caribbean through Antilles and flow westward at the depth of the subsurface salinity maximum. Our evidence shows that part of these waters are returned to the east by a Coastal Undercurrent where their salt content is modified by intense processes of vertical mixing with diluted surface waters. Eventually these modified SUW waters reaches the surface in the coastal upwelling areas off Colombia and Venezuela.