Tide gauges observe sea level changes, but are also affected by vertical land motion (VLM). Estimation of absolute sea level requires a correction for the local VLM. VLM is either estimated from GNSS observations or indirectly by subtracting tide gauge observations from satellite altimetry observations. Because altimetry and GNSS observations are often not made at the tide gauge location, the estimates vary. In this study we determine the best approach for both methods.

Global and regional sea level changes are the subject of public and scientific concern. Sea level data from satellite radar altimetry rely on precise knowledge of the orbits. We assess the orbit-related uncertainty of sea level on seasonal to decadal timescales for the 1990s from a set of TOPEX/Poseidon orbit solutions. Orbit errors may hinder the estimation of global mean sea level rise acceleration. The uncertainty of sea level trends due to orbit errors reaches regionally up to 1.2 mm yr⁻¹.

We calculate tidal velocities using observations of ocean currents collected by an underwater glider. We use these velocities to investigate the location of sharp boundaries between water masses in shallow seas. Narrow currents along these boundaries are important transport pathways around shallow seas for pollutants and organisms. Tides are an important control on boundary location in summer, but seawater salt concentration can also influence boundary location, especially in winter.

Parameters at the sea surface are determined by the air–sea fluxes of heat, salt, and momentum. Surface wind speed drives the oceanic surface circulation and mixing of temperature and salinity up to a certain depth (mixed layer depth) from the sea surface. In this study, we examined the oceanic mixing process using numerical models under strong cyclonic winds. Results highlight the important role of inertial oscillations in subsurface mixing.

A new three-dimensional data set of the horizontal velocity in the upper 2000 m that covers the years 1993 to 2015 is used to analyze the variability of the Benguela Current. This data set was derived using observations from Argo floats, satellite sea surface height, and wind fields. With this new observational data set, we identify the complex flow pattern in this region and provide a detailed analysis of the variability in the volume transport of this current.

The dominant circulation pattern of the Gulf of İzmir on the Aegean Sea coast of Turkey is studied taking into consideration the influence of wind and thermohaline forces. The free surface version of the Princeton model is applied with the input data obtained through the measurements made by the research vessel K. Piri Reis. As a result of the simulations with artificial wind, the strong consistent wind generates circulation patterns independent of the seasonal stratification in the Bay.

The future of Arctic marine ecosystems has received increasing attention in recent years as the extent of the sea ice cover is dwindling. Regional differences in the hydrography, bathymetry and atmospheric forcing of nutrient fluxes essential for phytoplankton growth mean that wind-driven mixing, advection and upwelling will influence the polar ecosystem in differing magnitudes in different regions of the Arctic Ocean, with particular effects likely being restricted to very specific areas.

With the objective of tackling the problem of inaccurate long-term ENSO forecasts, a new forecasting model of the SSTA field was proposed based on a dynamic system reconstruction idea and the principle of self-memorization. The improved model was used to forecast the SSTA field. The forecasted SSTA fields of three types of events are accurate. The improved model also has good forecasting results of the ENSO index. So our model has an advantage in ENSO prediction precision and length.

In June 2014, high-resolution oceanographic data were collected in the western Mediterranean Sea by two research vessels, 11 gliders, moored instruments, drifters, and one profiling float. The objective of this article is to provide an overview of the data set which is utilised by various ongoing studies, focusing on (i) water masses and circulation, (ii) operational forecasting, (iii) data assimilation, (iv) variability of the ocean, and (v) new payloads for gliders.