Argo floats are one of the main components of the in situ observation network in the ocean. Nowadays, more than 3500 profiling floats are sampling the world ocean. In this study, they are used to characterize spatial scales of temperature and salinity variations from the surface down to 1500m. The scales appear to be anisotropic and vary from about 100km at high latitudes to 700km in the Indian and Pacific equatorial and tropical regions.

The reference mean sea level (MSL) record, essential for understanding climate evolution, is derived from the altimetric measurements of the TOPEX/Poseidon mission, followed by Jason-1 and later Jason-2 on the same orbit. Soon, Jason-3 will be launched on the same historical orbit, followed by Sentinel-3a on a new one. This paper shows linking missions with the same orbit enables meeting climate user requirements regarding the MSL trend while using Sentinel-3a would increase the uncertainty.

Seasonal and interannual production changes in the northern Adriatic (NA) reflect on the total Adriatic bioproduction of certain species (i.e. anchovy). Long-term (1990-2004) phyto-abundance and geostrophic current analysis relieve the basic mechanism of NA biomass production changes. The results present a first step in building an empirical ecological model of the region, aiming to predict the amount of organic production in NA, which is to be used in the environmental management of the region.

High-resolution wave hindcast has been performed for the N Adriatic Sea using a hybrid methodology, combining a regional wave hindcast database, wind reanalysis, satellite SAR wind fields and data mining techniques. Comparison with in situ instrumental data indicates the good quality of the downscaled waves; moreover, a good correlation was found on the downscaled waves forced with different wind fields. Results demonstrate how SAR wind fields can be successfully up-taken in wave downscaling.

First modeling work comparing SHYFEM and MITgcm performance in the north Adriatic Sea; the treatment of heat/mass fluxes at the surface affects the models skill to reproduce coastal processes; high resolution is needed close to the coast, while lower resolution in the offshore is adequate to capture the dense water event; correct river discharges and temperature are vital for the reproduction of estuarine dynamics; non-hydrostatic processes do not influence the dense water formation.

We compare the northern Adriatic response to an extreme bora event, as simulated by one-way and two-way (i.e. with ocean feedback to the atmosphere) atmosphere-ocean coupling. We show that two-way coupling yields significantly better estimates of heat fluxes, most notably sensible heat flux, across the air-sea interface. When compared to observations in the northern Adriatic, two-way coupled system consequently leads to a better representation of ocean temperatures throughout the event.

The Civitavecchia Coastal Environment Monitoring System (C-CEMS) has been developed by the Laboratory of Experimental Oceanology and Marine Ecology in order to analyze the conflicts between human pressures and ecosystem conservation. As examples, the analysis of faecal bacteria dispersion for bathing water quality assessment and the evaluation of the effects of the dredged activities on Posidonia meadows are reported. Finally, C-CEMS can be considered a useful tool for coastal zone management.

In 2012 measurements were conducted in two adjacent estuary systems on Greenland’s western coast that are strongly influenced by glacial meltwater. Results described in this study show the relevance of inorganic SPM and Chl a alike, while colored dissolved organic matter is less prominent. Light availability was recorded throughout the cruise and an effective two-component (Chl a and inorganic SPM) model for PAR is developed to fill observational gaps from insufficient light conditions.

In this study, the influence of a spatio-temporally variable seawater conductivity on ocean-circulation-induced magnetic signals is investigated. To simulate the ocean-circulation-induced magnetic field, a combination of an ocean general circulation model (OMCT) and an electromagnetic induction model is used. It is found that a spatially varying seawater conductivity has a significant impact on the temporal variability of the induced magnetic field.

We investigate the rapidly changing equilibrium between the momentum sources and sinks during the passage of a single two-peak storm over the Catalan inner shelf (NW Mediterranean Sea). At 24m water depth, a primary momentum balance between acceleration, pressure gradient and frictional forces (surface and bottom) is established. The frictional adjustment timescale was around 10h, consistent with the e-folding time obtained from bottom drag parameterizations.

The subsurface circulation in the eastern tropical North Atlantic OMZ is derived from velocity, float and tracer data and data assimilation results, and shows a cyclonic flow around the Guinea Dome reaching into the oxygen minimum zone. The stronger cyclonic flow around the Guinea Dome in 2009 seem to be connected to a strong Atlantic Meridional Mode (AMM) event. A continuous deoxygenation trend of the low oxygen layer was confirmed. Eddy influence is weak south of the Cape Verde Islands.

The Barents Sea (BS) is a subpolar region and a zone transition where the Atlantic and the Arctic water masses meets and creates the "Polar Front". This study, based on one of the largest hydrological data set, showed for the first time that the "Polar Front" splits into two branches in the eastern part of the BS. This study also showed that, in a context of climate change, the BS experiences an "Atlantification", which goes along with a north-eastward shift of the frontal structure.

The NW Indian Ocean is the siege of two very intense anticyclonic eddies, the Great Whirl and the Southern Gyre, the rapid development of which makes their observation difficult. Model simulations propose an interaction scenario between the two eddies not described in observations up to now. When the summer monsoon intensifies, the Southern Gyre moves northward, collides with the Great Whirl and takes it place. The Great Whirl is pushed to the east of Socotra Island and forms the Socotra Eddy.

The paper investigates the role of vertical shear on the horizontal ocean dispersion of tracer particles or concentration fields. We compare in situ measurements to GCM numerical data of the magnitude and the typical timescale of the vertical shear. We discuss how an appropriate sub-grid-scale parameterization can account for an anomalous numerical shear dispersion due to the model poor time resolution. The analysis focuses on the mixing layer, and on the region of the south Mediterranean Sea.

The Met Office provides a range of services in the marine environment. To support these services, and to ensure they evolve to meet the demands of users and are based on the best available science, a number of scientific challenges need to be addressed. The paper summarises the key challenges, and highlights some priorities for the ocean monitoring and forecasting research group at the Met Office.

The interannual variation of the strength of the SAG in relation to NAO was studied. The intensity of the gyre is associated with the large-scale climatic variations via the wind-stress curl forcing. However due to the rather important contribution of the vorticity advection from the Ionian, which is more significant during the anticyclonic BiOS, there is no clear evidence of a direct effect of large-scale atmospheric circulation (NAO) on the interannual variability of the intensity of the SAG.

Satellite imagery reveals intense internal solitary waves (ISWs) seen hundreds of kilometres from the Amazon shelf and extending for 500 km into the open ocean (propagating above 3 m/s, amongst the fastest ever recorded). Seasonality is discussed in light of the North Equatorial Counter Current, and a late disintegration of the internal tide (IT) is investigated based on climatological data. A late disintegration of the IT may explain other ISW observations in the world’s oceans.

Argo profiling floats are continuously sampling the world ocean, providing temperature and salinity profiles of up to 2000 m depths. This article addresses the impact of the current Argo array on real-time ocean analyses and forecasts. One-year observing system experiments were carried out with the 0.25° global Mercator Ocean monitoring and forecasting system. The improvement due to the assimilation of the Argo profiles is estimated globally and regionally, showing a significant positive impact.

The variability of the relative salt composition in seawater may have significant influence on physical properties. Based on off-shore and laboratory measurements, this effect is quantified for the first time for speed of sound in Baltic seawater. Time-of-flight sensors with sufficient resolution were applied to resolve the small sound speed anomaly to values in the range of several cm s⁻¹. The results suggest that the effect can be reasonably predicted by the recent equation of state (TEOS-10).

A combined methodology to estimate time and space variable shoreline risk levels from ships has been developed, integrating metocean forecasts and oil spill simulations with vessel tracking automatic identification systems (AIS) and coastal vulnerability indices. Results show the ability of the proposed methodology to estimate the risk properly sensitive to dynamic metocean conditions and oil transport behaviour, enhancing the maritime situational awareness and the decision support model.

The article describes transient tracer distributions of CFC-12 and SF6 in the Fram Strait in 2012. The SF6 excess and the anthropogenic carbon content in this area was estimated assuming a standard parameterization of the inverse-Gaussian–transit-time distribution. Hydrographic data were obtained along a mooring array at 78°50’N and a mean velocity field was used for flux estimates.

We examine near-inertial variability of the meridional overturning circulation in the South China Sea (SCSMOC) using a global 1 / 12° ocean reanalysis. Based on wavelet analysis and power spectrum, we suggest that deep SCSMOC has a significant near-inertial band. The maximum amplitude of the near-inertial signal in the SCSMOC is nearly 4 Sv. The spatial structure of the signal features regularly alternating counterclockwise and clockwise overturning cells.