This paper describes the discovery of a previously unknown coastal upwelling centre on the western coast of Tasmania, Australia. This region forms part of the Great South Australian Coastal Upwelling System, which turns out one of the largest seasonal coastal upwelling systems on Earth. Upwelling events fuel phytoplankton blooms in last austral summer months and associated coastal jets are presumably an important nutrient source for the adjacent Bass Strait.

Dear Editor, Thank you for accepting the manuscript for publication in Ocean Science. We are submitting herewith the final version of the accepted manuscript. Thank you Sincerely, Shanmugam

The results of this study reveal that the thermohaline properties in the study area in 2011 lie between the thermohaline characteristics of the EMT and those of the pre-EMT phase, indicating a possible slow return towards the latter. It highlights the relationship between the hydrological property distribution of the upper layer in the Levantine basin and the alternate circulation regimes in the Ionian, which modulates the salinity distribution in the Eastern Mediterranean Sea.

This paper presents various respective data improvements achieved within the European Space Agency (ESA) Climate Change Initiative (ESA CCI) project on sea level during its first phase (2010-2013), using multi-mission satellite altimetry data over the 1993-2010 time span.

To protect from light stress, phytoplankton inhibit photosynthesis and suppress fluorescence through the process of quenching. This makes them invisible to fluorometers. Conventionally, quenching is corrected by taking maximum fluorescence yield in a surface mixed layer (MLD) and filling in the invisible proportion. This is only valid in waters where turbulence is high and phytoplankton are uniformly mixed. Here, we show that correcting from Zeu is a robust alternative to correcting from MLD

The hydrographical and ecological changes in the deep part of the Bornholm Basin in response to pumping well-oxygenated so-called winter water down to the greatest depth are investigated. By pumping 1000 m3s-1, the rates of water exchange and oxygen supply increase by 2.5 and 3 times, respectively. Anoxic bottoms should no longer occur and hypoxic events will become rare. This should mean much improved conditions for successful cod reproduction, extensive colonization of fauna on earlier periodi

A comparative study of simultaneous heat and gas exchange measurements was performed in the large annular Heidelberg Air-Sea Interaction Facility, the Aeolotron, under homogeneous water surface conditions, including the measurement of the Schmidt number exponent. Provided the Schmidt number exponent is known and that the heated patch is large enough to reach the thermal equilibrium, it is possible to scale heat transfer velocities measured by active thermography to gas transfer velocities.

Our article presents successful gas exchange measurements obtained in a large-scale wind-wave tank. The adopted box model methodology, experimental produce and instrumentation are described in detail. For the first time, parallel measurements of total transfer velocities for 14 individual gases within a wide range of solubility have been achieved. Various wind speed conditions and the effect of surfactant layers have been investigated providing exciting results.

We have developed a method to assess pigment concentrations from continuous optical measurements by applying an empirical orthogonal function analysis to remote-sensing reflectance data derived from hyperspectral ship-based and multispectral satellite measurements in the Atlantic Ocean. The method allows for the derivation of time series from continuous reflectance data of various pigment groups at various regions, which can be used to study phytoplankton composition and photophysiology.

This study examines the observed storm-generated sea-level variations at several Indian coastal locations in the Arabian Sea and the Bay of Bengal and identifies them as storm surges and harbour oscillations. The residual sea levels measured from sea-level stations in AS have been identified as Kelvin-type surges propagating northwards with almost constant amplitude. Multilinear regression analysis using local surface meteorological data is able to account for ~63% of daily mean sea level.

A wind-driven, spatially coherent mode of nonseasonal depth-independent variability in the Canadian inland seas is identified based on observational measurements and a numerical model over 2003--2013. This dominant mode of nonseasonal variability is partly related to the North Atlantic Oscillation. The mode is associated with net flows into and out of the Canadian inland seas as well as internal mass redistribution within the Canadian inland seas.

The present study defines new interpolation functions for hydrological data. These functions are applied to generate climatological maps of temperature-salinity distribution with a 25m depth interval and a 30km space interval (MEDTRANS data set). The MEDTRANS climatology gives more details of the distribution of water characteristics in the subtropical northeastern Atlantic than other alternative climatologies and is able to reproduce a number of dynamic features described in the literature.

Phytoplankton contribute to the regulation of the Earth's climate. In this study, we investigated the factors which affect the amount of nitrogen that phytoplankton in the Southern Ocean are able to use for their growth. We collected data during a winter cruise and a summer cruise. We found that in winter, day light and the amount of ammonium (a nitrogenous nutrient) were the two most important factors. In summer, it seems that the influx of nutrients (such as iron) plays a major role.

This study established a splitting strategy that could separate multinuclear eddies into mononuclear eddies. As the values of eddy parameters (e.g. SLA, geostrophic potential vorticity, Okubo–Weiss parameter) are similar to basins in a map, the natural divisions of the basins are the watersheds between them. It can also be applied to automatic identification of troughs and ridges from weather charts. We denoted it the Universal Splitting Technology for Circulations (USTC) method.

The accuracy of primary satellite ocean color data products from MODIS on-board Aqua and the VIIRS is investigated using in situ measurements from the ocean color component of the Aerosol Robotic Network (AERONET-OC). Results from the comparison of normalized water-leaving radiance LWN indicate biases of a few percent between satellite-derived and in situ data at the center wavelengths relevant for the determination of chlorophyll-a concentration.

Over the Yermak Plateau northwest of Svalbard there is substantial energy conversion from barotropic to internal tides. Internal tides are trapped along the topography. An approximate local conversion-to-dissipation balance is found over shallows and also in the deep part of the sloping flanks. Dissipation of tidal energy can be a significant contributor to turbulent mixing and cooling of the Atlantic layer in the Arctic Ocean.

Here, we investigated the seasonal variability of subsurface high-salinity water (SHSW) in the northern South China Sea (SCS) and its relationship with the North Equatorial Current-Kuroshio circulation system. Results give new insight into water exchange through the Luzon Strait (LS). The changes in western Pacific large-scale circulation modulate the water exchange in the LS, and thus influence the SHSW in the interior SCS basin.

The oceans are a key source of a number of atmospherically important volatile gases. The accurate and robust determination of trace gases in seawater is a significant analytical challenge. Here we describe a gas chromatograph mass spectrometer based purge and trap system that was developed for the fully automated analysis of dissolved very short-lived species (VSLS) in seawater sampled from a research ship.

The anthropogenic tritium invasion, and its decay product helium-3, was simulated for the first time in the Mediterranean Sea, using a high-resolution regional model (NEMO-MED12). The simulation covers the entire tritium (3H) transient generated by the atmospheric nuclear weapons tests performed in the 1950s and early 1960s and run until 2011. The model correctly simulates the main features of the thermohaline circulation in the Mediterranean Sea, with a realistic time compared to observations.

The Rockall Trough feeds warm salty water to Polar regions and the European Shelf. Detailed observations from an underwater glider show that a) the meandering surface current field in the central trough is driven by deep eddies; b) chance circulations deflect the eastern slope current and warm the western side; c) and altimeter observations omit the mean flow in the narrow slope current. There are wider implications for satellite altimeter observations, ocean monitoring and ocean model results.

Eddies in the South Indian Ocean (SIO) were statistically investigated based on 2082 surface drifters, and 19252 eddies were identified with 60% anticyclonic eddies. Mesoscale and submesoscale eddies show different spatial distributions. Large eddies mainly appear in regions with large eddy kinetic energy. The submesoscale anticyclonic eddies are densely distributed in the subtropical basin in the central SIO. The number of mesoscale eddies shows statistically significant seasonal variability.

The reproduction, survival, and transport of the comb jelly Mnemiopsis leidyi was studied with three models in the Scheldt estuaries and the southern North Sea. The results suggest that (a) the estuaries can retain an overwintering population and seed offshore populations; (b) M. leidyi can survive in the North Sea, and be transported between coastal inlets; and (c) M. leidyi cannot reproduce well in the North Sea, but this might change with global warming. The models need further improvement.

A realistic ocean circulation model is adapted to explicitly simulate model uncertainties and an ensemble data assimilation -stochastic perturbations, altimetric data and 4-D observation operator- is developed in order to control the Gulf Stream dynamic. The performance of the ensemble system is measured through probabilistic approach; the update then adjusts the bias and the dispersion of the ensemble (reliability) and reduces the uncertainty by 30% (resolution) for the SSH variable.

Seiches in coastal bays can produce significant water level oscillations that impact maritime operations and introduce ecological stress. Monterey Bay, California, is found to have wave-driven short-period oscillations that can reinforce themselves, resulting in water level amplification. At longer periods the oscillations are not wave-driven and several potential forcing mechanisms are examined. A gyre offshore the bay is suggested as the driver, while other potential drivers are discounted.

Mean circulation in the eastern tropical South Pacific in 50-600m depth is modified by seasonal variability and eddies on the poleward side of the oxygen minimum zone(OMZ). Floats with parking depth at 400m show westward flow in the equatorial channel, sluggish flow in the northern part of the OMZ, and passage of eddies with oxygen anomalies. Net community production rates were estimated from a float. Oxygen decrease in 50-300m depth since 1976 is related to an increase in nitrate and phosphate.

The atmospheric drivers of the Benguela upwelling systems and its variability are statistically analysed with an ocean-only simulation over the last decades. Atmospheric upwelling-favourable conditions are southerly wind/wind stress, a strong subtropical anticyclone, and an ocean-land sea level pressure gradient as well as a negative ENSO and a positive AAO phase. No long-term trends of upwelling and of ocean-minus-land air pressure gradients, as supposed by Bakun, can be seen in our analysis.

We describe the OceanFlux Greenhouse Gases methodology for creating an ocean surface CO2 climatology. In situ measurements valid for instantaneous sea surface temperature (SST) were recomputed using a more consistent and averaged SST. The results were normalised to year 2010, averaged by month, and interpolated onto a global 1°×1° grid. The 12 monthly distributions of ocean surface CO2 (see supplement) can be used in air-sea gas flux calculations together with climatologies of other variables.

The paper describes the analysis of wave energy along the coast of Sicily (Italy). A third-generation model was adopted to reconstruct the wave data along the coast over a period of 14 years. The analysis of the wave energy allowed characterising the most energetic zones and to individuate eight hotspots suitable for the implementation of wave energy converter farms.

Temperature fields in marine sediments are controlled by the geothermal steady state heat flow and the bottom water temperature. Thus, the current sediments' temperature field stores the history of bottom water temperature variation. The aim of this work is the inverse modeling of the bottom water temperature variation in the last year from instantaneous measurements of the depth-dependent temperature and the thermal diffusivity.

Marine biogeochemical ocean models are embedded into earth system models - which are, to an increasing degree, applied to project the fate of our warming world. These biogeochemical models generally depend on poorly constrained model parameters. In this study we investigate the the demands on observations for an objective estimation of such parameters. A major result is that even modest noise (10%) inherent to observations can hinder the assignment of reasonable parameters.

Many ocean circulation models use representations of lateral mixing based on instability theories that predict weak mixing in the ocean interior, much lower than observed. We show that using more realistic mixing improves the distribution of mantle helium-3. It does not, however, resolve the paradox that models reproduce the relationship between mantle helium and radiocarbon with a flux of helium-3 lower than is consistent with the heat leaving the mantle.

Changes in mass transport of the Florida Current induce significant coastal sea level changes along the Florida Straits and middle Atlantic coast of North America. Analysis of Florida Current transport data finds a decrease in mean transport over the last decade. This decrease coincides with a decrease in AMOC and acceleration of coastal sea levels along the Florida Straits.

Oceanic eddies are closed circulation features that transport water between regions, taking part in the ocean's heat and salt balance. We perform a comparative eddy census in the East Australian, Agulhas and Brazil currents. We find that eddy propagation in all systems is steered by the local mean flow and bathymetry. Also, eddies present a geographic segregation according to size. Investigating eddy propagation helps us to better understand their effect in local mixing.

An advanced tsunami generation, propagation and coastal inundation model is applied to simulate representative earthquake-induced tsunami scenarios in the Eastern Mediterranean. Two areas of interest were selected after evaluating tsunamigenic zones and possible sources in the region: one at the SE of Crete (Greece) and one at the E of Sicily (Italy). Results are indicative of the model’s capabilities, as well of how areas in the Eastern Mediterranean would be affected by eventual larger events.

The paper studies the impact of the use of relative winds (i.e., winds minus ocean currents) to compute heat and momentum fluxes at sea surface. This was done in an area interested by mesoscale eddies and a local boundary current. Impact is relevant both for heat and momentum fluxes. Major differences can be observed in areas with large mesoscale activity. Results suggest that surface currents component in fluxes computation should not be neglected even at such scales and latitudes.

The Arabian Sea and Sea of Oman have a complex oceanic circulation, strongly influenced by the monsoons. The aim of this article is to describe the mesoscale processes that dominate the region, large eddies with a strong vertical influence, with their seasonal and interannual variability, from their formations, evolutions and interactions. Thus, an emphasis is placed on the highly saline Persian Gulf outflow in the Sea of Oman, and its interaction with the mesoscale circulation.

This paper introduces a potential method for determining the salinity of the ocean surface from long-wave radio signals used for navigation (and potentially other AM radio transmissions). Here we seek to retrieve ocean surface salinity averaged along a path across the North Sea between Denmark and the UK and compare our results with satellite-derived salinity.

We use a suite of transient tracer measurements from a Southern Ocean sector southeast of Africa collected from 1998 and 2012 to quantify ventilation and change in ventilation. We found that the ventilation can be constrained by an inverse Gaussian transit time distribution north of the Subantarctic Front. We do not find any significant changes in upper ocean ventilation during this time period.

1. Argo floats were used to examine tropical cyclone (TC) induced ocean thermal changes on the global scale by comparing temperature profiles before and after TC passage. 2. Global average of the vertical structure of the average ocean thermal response for two different categories: tropical storms/depressions (TS/TD) and hurricanes were presented. 3. Significant differences between weak storm (TS/TD) and strong storm (hurricane) were found.

The Faroe Current is the main ocean current transporting warm Atlantic water into the Arctic region and an important transporter of heat towards the Arctic. This study documents observed transport variations over two decades, from 1993 to 2013. It shows that the volume transport of Atlantic water in this current increased by 9% over the period, whereas the heat transport increased by 18%. This increase will have contributed to the observed warming and sea ice decline in the Arctic.

We describe the seasonal and year-to-year variability of the spatial distribution of the phytoplankton size classes (PSCs) in the Mediterranean Sea using the time series of Sea-viewing Wide Field-of-view Sensor (SeaWiFS) observations (1998 to 2010). We used a chlorophyll-a-based model to estimate the phytoplankton composition. Our results, based on ocean colour data, confirm the seasonal and inter-annual pattern of the phytoplankton community observed from in situ data and in previous studies.

A method which determines the radiance reflectance at the surface as well as the water-leaving and reflected radiances solely from the measurements of upward nadir radiance and downward irradiance in air is presented. A comparison between this method and in situ measurements shows that the average relative deviations between their results are less than or equal to 15% for the reflected radiance, at the studied wavelengths.

The altimetry data assimilation requires the addition of the mean dynamic topography to the altimetric sea level anomaly to match the model sea surface height. The mean dynamic topography is usually computed from the model long-term mean sea surface height. In this study, the impact of different mean dynamic topographies on the sea level anomaly assimilation is examined. Results show that impacts of the mean dynamic topography cannot be neglected.

Results from the ECCO v4 ocean state estimate identify the constraint of fitting Argo profiles as an effective observational basis for inverse estimation of regional turbulent transport rates. The estimated parameters' geography is physically plausible and exhibits close connections with the observed upper-ocean stratification. They yield a clear reduction in the model drift away from observations over multi-century-long simulations, including for independent biochemistry variables.

Quasi-regular eddies are known to be generated in the outflow of dense water through the Faroe Bank Channel. One year long mooring records from the plume region show that (1) the energy associated with the eddies varies by a factor of 10 throughout the year and (2) the frequency of the eddies shifts between 3 and 6 days and is related to the strength of the outflow. Similar variability is shown by a high-resolution regional model and the observations agree with theory on baroclinic instability.

The sea surface temperature (SST) anomalies in the South China Sea (SCS) and their influences on global atmospheric circulation were studied. The results of the simple atmospheric model suggested that the SCS SST anomalies can induce several barotropic wave trains from the SCS to other regions. The baroclinic stream function anomalies from the simple model showed an anticyclonic vortex pair and a cyclonic vortex pair.

Automated measurement systems called FerryBox are installed on cargo ships in the North Sea. Operational model forecasts have been compared to FerryBox data of water temperature and salinity. We wanted to know how well the simulations agree with the observations. We found out that water temperature simulation gives satisfying results, while salinity simulation still could be improved. It turned out that assimilation of observational data into operational models gives strong benefits.

The IEO-RADMED monitoring program is already conducting many of the evaluations required under the Marine Strategy Framework Directive (MFSD) along the Spanish Mediterranean coast. The different aspects of the ecosystem that are regularly sampled under this monitoring program are the physical environment and the chemical and biological variables of the water column, together with the planktonic communities, biomass and structure.

Sea surface temperature and turbidity, derived from satellite imagery, were used to characterize river plumes in the northern Adriatic Sea during a significant flood event in November 2014. Circulation patterns and sea surface salinity, from an operational coupled ocean-wave model, supported the interpretation of the plumes' interaction with the receiving waters and among them.

In this paper, we provide a detailed description of basic sea surface circulation features in the Ebro River delta (NW Mediterranean) as derived from reliable high-frequency radar surface current measurements. An integrated quality control approach has been applied to ensure the acquisition of accurate radar data, which remains a priority for the research community. This work should be of interest to readers in the areas of operational oceanography and also to a broad community of end-users.

We assess benzalkonium chloride (BAC) as alternative to mercuric chloride (HgCl2) for preservation of seawater samples. BAC concentrations of 50mg dm–3 inhibited microbial activity for at least 3 days in samples tested with chlorophyll a concentrations up to 1mg m–3. With fewer risks to health and environment, and lower waste disposal costs, BAC could be a short-term alternative to HgCl2, but cannot replace it for oxygen triple isotope samples, which require storage over weeks to months.

The Atlantic Meridional Overturning Circulation (AMOC) is a key mechanism for large-scale northward heat transport and plays an important role for global climate. Previously, AMOC changes have been inferred from in situ ocean bottom pressure (OBP) observations at single latitudes. We extend the analysis to space-based observations (and the whole North Atlantic) and show on data from the ECCO2 model that AMOC anomalies can be inferred from OBP at a resolution resembling the GRACE gravity mission.

Helium isotopes are a powerful tool in Earth sciences. We present the first simulation of the terrigenic helium isotope distribution in the whole Mediterranean Sea, using a high-resolution model (NEMO-MED12). In addition to providing constraints on helium isotope degassing fluxes in the Mediterranean, our simulations provide information on the ventilation of the deep Mediterranean waters, which are useful for assessing NEMO-MED12 performance.