In ocean models, Antarctic Bottom Water (AABW) formation is frequently misrepresented. Hence, assessing the causes of spurious formation is important to ensure accurate future simulations. Only one of the state-of-art reanalyses investigated showed AABW formation accurately. Spurious formation in the other two products resulted from opening of open ocean polynyas. The relatively accurate AABW formation in one of the products is an important advance in the simulation of deep ocean circulation.

On its way towards the Arctic, an important branch of warm Atlantic water passes through the Faroese Channels, but, in spite of more than a century of investigations, the detailed flow pattern through this channel system has not been resolved. This has strong implications for estimates of oceanic heat transport towards the Arctic. Here, we combine observations from various sources, which together paint a coherent picture of the Atlantic water flow and heat transport through this channel system.

The hydrography and circulation west of Sardinia, observed in June 2014 during REP14-MED by means of various measuring platforms, are presented and compared with previous knowledge. So far, the circulation of this area is not well-known and the hydrography is subject to long-term changes. The different water masses are characterized and temporal changes are emphasized. The observed eddies are specified and geostrophic transports in the upper ocean are presented.

The dispersion of coastal waters offshore strongly depends on the dynamical regime of the current that characterizes the local coastal circulation. By using an idealized model configuration, we identify some key parameters – which can be calculated from observations – that describe when a coastal current flowing over a sloping topography acts as a source of meanders or eddies or as a dynamical barrier to the cross-shore transport.

An ocean prediction model was driven by observations via assimilation. The best forecast was obtained using a smoothing scale of 12.5 km and a time window of 24 h for data selection. Mostly, the forecasts were better than that of a run without assimilation, the skill score increased with increasing forecast range, and the score for temperature was higher than the score for salinity. It is shown that a vast number of data can be managed by the applied method without data reduction.

This paper reports the analysis of 3-week oceanographic data obtained in the front of Flade Isblink Glacier in northeast Greenland. The major focus of research is considering the changes of water dynamics and the altering of temperature and salinity vertical distribution occurring during the storm event. We discuss the mechanisms that are responsible for the formation of two-layer circulation cell and release of cold and relatively fresh sub-glacial waters into the ocean.

During a 4-week oceanographic cruise in 2012, we investigated the water masses bordering the subtropical front near New Zealand as sources of the biogenic gas dimethyl sulfide (DMS). DMS oxidation products may influence the atmospheric radiative budget of the Earth. Concentrations of DMS were high in the study region and DMS's precursor, dimethylsulfoniopropionate, showed a strong association with phytoplankton biomass in relation to the persistent dominance of dinoflagellates/coccolithophores.

High-resolution measurements of temperature, salinity, and the stable oxygen isotope ratio of seawater were collected along the slopes of the Barents, Kara, and Laptev seas during late summer of 2013 and 2015. Two separate mixing regimes were identified that describe the initial and final stages of halocline water formation. The linear regressions defining the mixing regimes appear to be stable despite the dramatic environmental changes observed over the Arctic Ocean over the past two decades.

The study of the outer shelf and the continental slope waters of the Eurasian Arctic seas has revealed a general trend in the surface pCO₂ distribution, which manifested as an increase in pCO₂ values eastward. It has been shown that the influence of terrestrial discharge on the carbonate system of East Siberian Arctic sea surface waters is not limited to the shallow shelf and that contemporary climate change impacts the carbon cycle of the Eurasian Arctic Ocean and influences air–sea CO₂ flux.

Observations and numerical models reveal the existence of the subsurface current in the opposite direction to the surface current off the Sri Lankan east coast. The undercurrent (200–1000 m layer) is most pronounced during the boreal spring and summer and transports more mass than the surface layer (0–200 m). Although the undercurrent is potentially a pathway of salt exchange between the Arabian Sea and the Bay of Bengal, the data and models suggest little salt transport by the undercurrent.

Using field observations we studied the effects that the narrow contraction in the Little Belt, one of the three straits connecting the Baltic Sea and the North Sea, has on currents and water masses. We found the existence of internal hydraulic control, a phenomenon well-known from theoretical and laboratory studies, but surprisingly rarely observed in nature. This phenomenon plays an enormous role due to intense mixing between the water masses, which may drive a highly productive ecosystem.