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A significant proportion of global carbon dioxide emissions are attributed to ocean-sailing ships and shipping emissions are predicted to double in less than 30 years. This paper investigates the benefit of using weather ship routing optimisation, assessing the ship emissions for minimum distance routes and optimised routes. The present contribution merges the estimation of shipping pollutants and their mitigation through weather routing optimisation; two lines of research widely analysed separately but seldom discussed together. A previously developed open software of weather ship routing is used to obtain the minimum cost (i.e. optimised route) in terms of sailing time, using high-resolution wave forecasting. The assessment of fuel consumption and ship emissions calculations were inspired by the STEAM2 bottom-up approach, in conjunction with the estimation of the power increase needed to overcome speed decrement due to waves. Several scenarios covering the Western Mediterranean Short Sea Shipping routes (from 24 to 600 nautical miles and using a real Ro-Pax vessel) are compared in terms of emissions between the minimum distance route and the optimum. The ship routing optimisation reveals a reduction up to 30% of ship emissions during severe storms on longer routes. Nevertheless, all the cases studied show emissions mitigation when ship routing optimisation is used. The expected increase of extreme weather events, in terms of frequency, intensity and duration due to climate change, suggests a gradual gain of implementing weather ship routing optimisation in all types of routes, regardless of the distance.

This contribution investigates the latest concentration tendency of Yangtze River Delta (YRD) multi-port system with concentration-ratio, Herfindahl-Hirschman-Index and shift-share-analysis. Results show that Zhejiang is the major winner; Shanghai is losing its oligopoly since 2012; Shanghai, Zhejiang and Jiangsu are reaching tripartite equilibrium. Then, ARIMA, linear regression and GM (1, 1) are used to forecast container throughput of Shanghai, Zhejiang, Jiangsu and YRD. By mean absolute percent error (MAPE), all models have good or reasonable performance, ARIMA performs best with MAPE of 2.37%, 2.41% and 6.54% when time series seem linear, however does not has excellent performance (MAPE is 14.26%) when non-linear. Finally, we use the indirect and direct method to forecast; MAPE decreases to 3.85% using ARIMA, which supports the out-performance of indirect forecast. The combination of concentration index analysis and forecasting methods has allowed to gain insight in the evolution and prospects of YRD container multi-port system.

This contribution investigates the container throughput flow in a multi-port gateway system: Barcelona-Tarragona-Valencia (BTV). First, the paper examines the recent dynamics of the total and transhipment flow showing a relevant shifting of traffic share from Barcelona to Valencia. A novel model based on a two-state Markov model in conjunction with a Monte Carlo experiments is implemented to estimate the predictions of annual growth in container throughput. Verification tests show how the predictions are reasonably good with error metrics similar to other methods based on timeseries analysis (trend projections and ARIMA). The strength of the method relies in the statistical nature of the predictions provided (i.e., mean and data dispersion). The method is considered suitable for short-term forecasting. The practical application of the method considers separately the import/export and transhipment container throughput, revealing a different dynamics in both container flows.

Weather ship routing has become a recognized measure to target safe, sustainable and economical ship activities. Academic research has focused the ship routing optimization through pathfinding algorithms which take into account the meteo-oceanographic forecasts (i.e. wind, waves or currents predictions). This contribution shows the results of the numerical simulations carried out during the development of a weather ship routing applied to a ferry service in the Mediterranean Sea: Barcelona – Palma de Mallorca. From a methodological point of view, the pathfinding A* algorithm is applied to optimize the travel time considering the wave action. Under severe weather conditions, a reduction of the 7% of the travel time is obtained comparing the optimized route and the minimum distance route. The results show also a non-significant correlation between the travel time reduction and wave height. In consequence the benefit of ship routing depends not only of the wave height but also in the spatial sequence of the storm.

The dynamical response to cross‐shelf wind‐jet episodes is investigated. The study area is located at the northern margin of the Ebro Shelf, in the Northwestern (NW) Mediterranean Sea, where episodes of strong northwesterly wind occur. In this case, the wind is channeled through the Ebro Valley and intensifies upon reaching the sea, resulting in a wind jet. The wind‐jet response in terms of water circulation and vertical density structure is investigated using a numerical model. The numerical outputs agree with water current observations from a high‐frequency radar. Additionally, temperature, sea level, and wind measurements are also used for the skill assessment of the model. For the wind‐jet episodes, the numerical results show a well‐defined two‐layer circulation in the cross‐shelf direction, with the surface currents in the direction of the wind. This pattern is consistent with sea level set‐down due to the wind effect. The comparison of the vertical structure response for different episodes revealed that the increase of stratification leads to an onshore displacement of the transition from inner shelf to mid‐shelf. In general, the cross‐shelf momentum balance during a wind‐jet episode exhibits a balance between the frictional terms and the pressure gradient in shallow waters, shifting to a balance between the Coriolis force and the wind stress terms in deeper waters. The shelf circulation induced by cross‐shelf wind jets is investigated using the ROMS model and data measurements from buoys and a HF radarThe results show a sea level set‐down near the coastline and a two‐layer circulation in the cross‐shelf directionThe cross‐shelf momentum balance during a wind‐jet event shows different balancing terms at shallow and deep regions

This study characterizes the seasonal cycle of the Catalan inner‐shelf circulation using observations and complementary numerical results. The relation between seasonal circulation and forcing mechanisms is explored through the depth‐averaged momentum balance, for the period between May 2010 and April 2011, when velocity observations were partially available. The monthly‐mean along‐shelf flow is mainly controlled by the along‐shelf pressure gradient and by surface and bottom stresses. During summer, fall, and winter, the along‐shelf momentum balance is dominated by the barotropic pressure gradient and local winds. During spring, both wind stress and pressure gradient act in the same direction and are compensated by bottom stress. In the cross‐shelf direction the dominant forces are in geostrophic balance, consistent with dynamic altimetry data. A hydrodynamic model is implemented for the first time in Catalan inner‐shelf.Frictional and pressure gradient are revealed as the main forcing mechanismsA clear seasonal pattern is found in the current velocity