Spectral analyses of along-track altimetric data are used to estimate noise levels and observable ocean scales in the NW Mediterranean Sea. In winter, all altimetric missions can observe wavelengths down to 40–50 km (individual feature diameters of 20–25 km). In summer, SARAL can detect scales down to 35 km, whereas Jason-2 and CryoSat-2 with higher noise can only observe scales less than 50–55 km. Along-track altimeter data are also compared with collocated glider and coastal HF radar data.

The relevance of including the wave effect into a nearshore circulation model is discussed. Two different approaches are tested in the framework of an operational forecast system. It is shown that the waves are essential to represent the circulation patterns near the coast. While it seams to be ideal to consider the full coupling between surface waves and ocean currents, a computationally cheaper alternative is tested and shown to give equivalent qualitative results.

An important contribution to future changes in regional sea level extremes is due to the changes in intrinsic ocean variability, in particular ocean eddies. Here, we study a scenario of future dynamic sea level (DSL) extremes using a strongly eddying version of the Parallel Ocean Program. Changes in 10-year return time DSL extremes are very inhomogeneous over the globe and are related to changes in ocean currents and corresponding regional shifts in ocean eddy pathways.

We evaluated if numerical model output helps us to better estimate the physical forcing that drives the air–sea gas exchange rate (k) in sea ice zones. We used 36, 9 and 2 km horizontal resolution of regional MITgcm configuration with fine vertical spacing to evaluate the capability of the model to reproduce sea ice velocity, concentration, mixed layer depth and water velocities. We found that even the coarse-resolution model can make a modest contribution to gas exchange parameterization.

Velocity measurements from moorings at the shelf break in the southern Weddell Sea reveal strong diurnal tidal currents, which are enhanced by ca. 50 % in austral summer compared to winter. A numerical code describing coastal trapped waves (CTWs) is used to explore the effect of changing stratification and circulation on wave properties. It is found that near-resonance between CTWs and diurnal tides during austral summer can explain the observed enhancement of diurnal tidal currents.

The significant wave height (Hs) is one of the most relevant parameters to describe a sea state statistically. This parameter is commonly monitored by measurement devices placed in the water (wave rider buoy, ADCP), which require expensive maintenance. In this study, X-band radar, generally used for ship navigation, was modified to measure water particle speeds using the Doppler effect. Based on the obtained data, a simple method is introduced to remotely estimate Hs with a reasonable accuracy.

Research on the summer TWC has been conducted previously; however, the spatial structure and temporal variation of the winter TWC are less known due to its weak mean velocity. Therefore, FVCOM was used to evaluate the spatial patterns of TWC synoptic fluctuations. We observed that the TWC fluctuations appear mainly to the north of Taiwan and in the inshore area. Our results will be useful in the dynamical understanding of the winter TWC and its impact on cross-shore transport.

The Arctic Ocean plays an important role in the global climate system, but the concerned interpretation about its changes is severely hampered by the sparseness of the observations of sea ice and ocean. The focus of this study is to provide a quantitative assessment of the performance of the TOPAZ4 reanalysis for ocean and sea ice variables in the pan-Arctic region (north of 63 °N) in order to guide the user through its skills and limitations.

Here we present the results of an intensive physical oceanography study conducted in the Reloncavi fjord (41.5º S, 72.5º W) which was focused on the sub-inertial timescale. The along-fjord currents presented 3-day oscillations which were consistent with the natural internal period of oscillation of the fjord basin (internal seiche). This oscillation could explain more than 44 % of the 3-day variability and contributed with kinetic energy levels as large as the tidal currents.

COSYNA (Coastal Observing System for Northern and Arctic Seas) pursued various activities for stakeholder interaction. The steps, e.g. initial survey, external evaluation, interviews and workshops with stakeholders from the offshore wind sector, are integrated into the COSYNA product life cycle outlined here and exemplified for the product Surface Current Fields. By sharing first-hand experiences this study contributes to the emerging knowledge on integration of coastal research and end users.

This study investigates the variability of the Deep Western Boundary Current at 34.5° S. This current carries a large part of the cold deep limb of the Meridional Overturning Circulation, which is a crucial part of the ocean system and has impacts on global weather patterns. Study of this current in the South Atlantic has been limited in the past, and this new study provides insights into the strength and variability of the current as well as the causes for the observed changes.