Since the mid-1990s, a series of FES (finite element solution) global ocean tidal atlases has been produced with the primary objective to provide altimetry missions with a tidal de-aliasing correction. We describe the underlying hydrodynamic/data assimilation design and accuracy assessments for the FES2014 release. The FES2014 atlas shows overall improved performance and has consequently been integrated in satellite altimetry and gravimetric data processing and adopted in ITRF standards.

We quantify the mesoscale eddy field in the Lofoten Basin using Lagrangian model trajectories and aim to estimate the relative importance of eddies compared to the ambient flow in transporting warm Atlantic Water to the Lofoten Basin as well as modifying it. Water properties are largely changed in eddies compared to the ambient flow. However, only a relatively small fraction of eddies is detected in the basin. The ambient flow therefore dominates the heat transport to the Lofoten Basin.

Multispectral optical sensors and models are increasingly adopted to study marine systems. In this work, bio-optical mooring and biogeochemical Argo float optical observations are combined with the Ocean-Atmosphere Spectral Irradiance Model (OASIM) to analyse the variability of sunlight at the sea surface. We show that the model skill in simulating data varies according to the wavelength of light and temporal scale considered and that it is significantly affected by cloud dynamics.

This modelling study describes a methodology for describing pollutant discharges from ships to the sea. The pilot area used is the Baltic Sea area and discharges of bilge, ballast, sewage, wash water as well as stern tube oil are reported for the year 2012. This work also reports the release of SO_x scrubber effluents. This technique may be used by ships to comply with tight sulfur limits inside Emission Control Areas, but it also introduces a new pollutant stream from ships to the sea.

We investigate how the freshwater budget of the Atlantic changes under climate change, which has implications for the stability of the Atlantic Meridional Overturning Circulation. We compare the effect of ocean model resolution in a climate model and find many similarities between the simulations, enhancing trust in the current generation of climate models. However, ocean biases are reduced in the strongly eddying simulation, and significant local freshwater budget differences exist.

High-frequency radar technology measures coastal ocean surface currents. The use of this technology is increasing as it provides near-real-time information that can be used in oil spill or search-and-rescue emergencies to forecast the trajectories of floating objects. In this work, an analog-based short-term prediction methodology is presented, and it provides surface current forecasts of up to 48 h. The primary advantage is that it is easily implemented in real time.

The circulation patterns in the confluence of the North Atlantic subtropical and tropical gyres delimited by the Cape Verde Front were examined during a field cruise in summer 2017. The collected hydrographic data, O₂ and inorganic nutrients along the perimeter of a closed box embracing the Cape Verde Frontal Zone allowed for the independent estimation of the transport of these properties.

Satellite altimetry has revolutionized ocean observation by allowing the sea level to be monitored with very good spatiotemporal coverage. However, only the sea level anomalies are retrieved; to monitor the whole oceanic signal a temporal mean (called mean dynamic topography, MDT) must be added to these anomalies. In this study we present the newly updated CNES-CLS18 MDT. An evaluation of this new solution shows significant improvements in both strong currents and coastal areas.

This special issue marks the 100th anniversary of the founding of the Liverpool Tidal Institute (LTI). The preface gives a history of the LTI founding and of its first two directors. It also gives an overview of LTI research on tides. Summaries are given of the 26 papers in the special issue. Their topics could be thought of as providing a continuation of the research first undertaken at the LTI. They provide an interesting snapshot of work on tides now being made by groups around the world.

We tested the stability of a well-characterized seawater pH buffer, tris, during long-term storage in gas-impermeable bags. Tris is used to validate pH measurements; it is critical that we understand how its chemistry changes over time. Correspondingly, we prepared multiple batches of tris buffer in artificial seawater, stored the buffer in multiple types of gas impermeable bags, and analyzed its pH over the course of 300 d, discovering an average change of −0.006 yr⁻¹.

Six tropical areas in the Pacific, Atlantic and Indian oceans were investigated for trends for the years since 1950 for temperature, salinity, oxygen and nutrients at 50 to 300 m and 300 to 700 m depth. Generally, temperature increases, oxygen decreases and nutrients often increase. Overlain variability on the trends seem to be related to climate modes. Different trends indicate that oxygen and nutrient trends cannot by completely explained by local warming.

The ocean is a turbulent system, full of meandering currents and fronts of various scales. These processes can influence the distribution of microscopic algae or phytoplankton by upwelling deep, nutrient-rich waters to the sunlit surface or by actively gathering and accumulating them. Our results suggest that, at the surface, salinity is the main conditioning factor for phytoplankton distribution. However, at the subsurface, oceanic currents influence phytoplankton distribution the most.