In this contribution we investigate the hydrodynamic response in Alfacs Bay (Delta Ebro, NW Mediterranean Sea) to freshwater flows and inner bay to open sea connections. The numerical model ROMS is applied nested to Copernicus models and validated with in situ data. Considering the results, only the modification of freshwater flows is recommended due to its lower impact on the environment and associated economic costs. None of the proposed solutions solve the problem related to warm waters.

We carry out an inter-comparison of four different altimeters: Cryosat, Jason-2, Jason-3, and Sentinel-3. This is undertaken by checking the altimeter data against wind and wave model results for a given area, in this case the Mediterranean Sea, over 1 year. The four data sets are consistent for wind speed, but they show substantial differences for wave heights. The verification of a Sentinel-3 pass close to the coast in the northern Adriatic Sea shows irregular, spiky, large wave height values.

Errors of observations and numerical model data are analysed with a focus on heterogeneous coastal areas. An extension of the triple collocation method is proposed, which takes into account gradients in the collocation of datasets separated by distances which may not be acceptable for a nearest-neigbour approximation, but still be feasible for linear or higher order interpolations. The technique is applied to wave height data from in situ stations, models, and the Sentinel-3A altimeter.

This study uses different in situ and satellite measurements to investigate ocean circulation in the NW Mediterranean Sea. We analyze how the different instruments (satellite altimetry, HF radars, gliders, ADCPs) capture current variability and how they complement each other. We demonstrate the ability of satellite altimetry to capture the fluctuations of the narrow coastal Northern Current at different timescales. This study provides an integrated approach to a coastal dynamics study.

In operational oceanography, regional and local models use large-scale models (such as those run by CMEMS) for their initial and/or boundary conditions, but unfortunately there is no feedback that improves the large-scale models. The present study aims at replacing normal two-way nesting by a data assimilation technique. This upscaling method is tried out in the north-western Mediterranean Sea using the NEMO model and shows that the basin-scale model does indeed benefit from the nested model.

In this paper we investigate the origin of the variability in near-bottom turbidity observations in Alfacs Bay (in the northwestern Mediterranean Sea). The observations of turbidity peaks are consistent with the seiche phenomenon. We suggest that the sequence of resuspension events plays an important role in the suspended sediment concentration, meaning that previous sediment resuspension events may influence the increase in suspended sediment in subsequent events.

The resonant period of the Gulf of Thailand is potentially close to 1 day. However, the classic quarter-wavelength resonant theory fails to give a diurnal resonant period. In this study, we first perform a series of numerical experiments showing that the resonance of the South China Sea body has a critical impact on the resonance of the gulf. An idealised two-channel model that can reasonably explain the dynamics of the tidal resonance in the Gulf of Thailand is then established in this study.

Sea surface temperature (SST) is related to ocean heat content, an important topic in the debate over global warming. In this paper, we propose a novel SST-predicting method based on the hybrid improved EMD algorithms and BP neural network method. SST prediction results based on the hybrid EEMD-BPNN and CEEMD-BPNN models are compared and discussed. A case study of SST in the North Pacific shows that the proposed hybrid CEEMD-BPNN model can effectively predict the time-series SST.

Ocean surface waves generated by wind and dissipated by white capping are two important physics processes for numerical wave simulations. In this study, a new pair of wind–wave generation and dissipation source functions is implemented in the wave model SWAN, and it shows better performance in real wave simulations during two North Sea storms. The new source functions can be further used in other wave models for both academic and engineering purposes.

Two decades of observations of the Arctic Mediterranean (AM) exchanges show that the exchanges have been stable in terms of volume transport during a period when many other components of the global climate system have changed. The total AM import is found to be 9.1 Sv and has a seasonal variation in amplitude close to 1 Sv, and maximum import in October. Roughly one-third of the imported water leaves the AM as surface outflow.

A novel predictive model is built for eddy propagation trajectory using the multiple linear regression method. This model relates various oceanic parameters to eddy propagation position changes in the northern South China Sea (NSCS). Its performance is examined in the NSCS based on five years of satellite altimeter data, and demonstrates its significant forecasting skills over a 4-week forecast window compared to the traditional persistence method.

Mesoscale eddies are large bodies of swirling water, which generally refer to ocean signals with spatial scales of tens to hundreds of kilometers and temporal scales of days to months. This study identified events of splitting and merging of mesoscale eddies in the global ocean based on sea level height data. Multicore structures represent an intermediate stage in the process of eddy evolution, similar to the generation of multiple nuclei in a cell as a preparatory phase for cell division.

This is the first investigation of the worldwide distribution of the degree-3 M1 ocean tide using over 800 tide gauge records and a global tide model. M1 is confirmed to have a geographical variation in the Atlantic and other basins consistent with the suggestion of Platzman and Cartwright that M1 is generated through the spatial and temporal overlap of M1 in the tidal potential and one (or at least a small number of) diurnal ocean normal mode(s).

To better exploit the observational information available for all scales in data assimilation systems, we investigate a new method to introduce scale separation in the algorithm. It consists in carrying out the analysis with spectral localisation for the large scales and spatial localisation for the residual scales. The performance is then checked explicitly and separately for all scales. Results show that accuracy can be improved for the large scales while preserving reliability at all scales.

This study investigates the deep gravity current between the middle and southern Caspian Sea basins. Oceanographic data, a numerical model and dynamic models are used to consider the structure of this abyssal overflow. The deep overflow is driven by the density difference – mainly due to the temperature difference between the middle and southern basins – especially in winter. The deep flow may be an important factor influencing oil pollution in the deeper region of the southern Caspian Sea.