Recent  

In our laboratory experiments we addressed the question of how surface standing waves in a closed stratified basin are damped by the interaction of the flow in the bulk with a sill-like bottom obstacle reaching up to a density interface between the more saline deep layer and the freshwater layer at the top. We quantify the decay rates of the surface waves and explore what types of internal waves can be excited in this process along the internal density interface.

We develop a method for monitoring zooplankton while controlling key environmental conditions at precise depths in the sea. We apply a profiler with an acoustic device to observe the sound-scattering layers formed by zooplankton species that descend for several tens of meters every day all year round and by persistent aggregations of the resting stage of copepods under very low concentrations of dissolved oxygen (below 10 μM L⁻¹) from spring to late autumn.

Experiments in rotating tanks can simulate the Earth system and help to represent the real ocean, where rotation plays an important role. We wanted to show the minor importance of the wind in driving the flow in the Ionian Sea. We did this by observing changes in the water current in a rotating tank affected only by the pumping of dense water into the system. The flow variations were similar to those in the real sea, confirming the scarce importance of the wind for the flow in the Ionian Sea.

The ocean absorbs a large proportion of the excess heat and anthropogenic carbon in the climate system. This uptake is modulated by air–sea fluxes and by the processes that transport water from the surface into the ocean’s interior. We performed numerical simulations with interannually varying passive tracers and identified the key role of surface atmospheric forcing in setting the longer-term variability in the distribution of the tracers after they are transported below the ocean’s surface.

The wind is a source of uncertainty in oil spill modeling. We performed oil spill ensemble simulations using an atmospheric ensemble to quantify this uncertainty. We investigate the reliability of oil spill ensemble prediction used as an important forecasting tool to better plan mitigation procedures in the event of an oil spill.

Based on the near-synchronous oceanographic and ocean chemical data from 2006 to 2007, the present paper shows the magnitude, distribution characteristics, and formation mechanism of Absolute Salinity in China offshore waters. These results are valuable supplements for the new worldwide standard for oceanography, The international thermodynamic equation of seawater – 2010, in which the Absolute Salinity algorithm is not very clear to date for offshore and semi-closed sea due to the lack of data.

Little is known about the impact of chlorophyll on SST in the Bay of Bengal (BoB). Solar irradiance measured by an ocean glider and three Argo floats is used to determine the effect of chlorophyll on BoB SST during the 2016 summer monsoon. The Southwest Monsoon Current has high chlorophyll concentrations (∼0.5 mg m⁻³) and shallow solar penetration depths (∼14 m). Ocean mixed layer model simulations show that SST increases by 0.35°C per month, with the potential to influence monsoon rainfall.

This paper presents an efficient method for high-resolution ocean modelling based on a combination of the deterministic and stochastic approaches. The method utilises mathematical tools similar to those developed for data assimilation in ocean modelling. The main difference is that instead of assimilating a relatively small number of observations, the SDD method assimilates all the data produced by a parent model. The method is applied to create an operational Stochastic Model of the Red Sea.

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.

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.

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.

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.

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.

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.

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.