We present ice-free and ice-included statistics for the Baltic Sea using a wave hindcast validated against data from 13 wave measurement sites. In the hindcast 84% of wave events with a significant wave height over 7 m occurred between November and January. The effect of the ice cover is largest in the Bay of Bothnia, where the mean significant wave height is reduced by 30% when the ice time is included in the statistics. The difference between these two statistics are less than 0.05 m below a latitude of 59.5°. The seasonal ice cover also causes measurement gaps by forcing an early recovery of the instruments. Including the time not captured by the wave buoy can affect the estimates for the significant wave height by roughly 20%. The impact below the 99 th percentiles are still under 5%. The significant wave height is modelled accurately even close to the shore, but the highest peak periods are underestimated in a narrow bay. Sensitivity test show that this underestimation is most likely caused by an excessive refraction towards the shore. Reconsidering the role of the spatial resolution and the physical processes affecting the low-frequency waves is suggested as a possible solution.

This paper presents the results of a wave hindcast of a severe storm in the Southern North Sea to verify recently developed deep and shallow water source terms. The work was carried out in the framework of the ONR funded NOPP project (Tolman et al. 2013) in which deep and shallow water source terms were developed for use in third-generation wave prediction models. These deep water source terms for whitecapping, wind input and nonlinear interactions were developed, implemented and tested primarily in the WAVEWATCH III model, whereas shallow water source terms for depth-limited wave breaking and triad interactions were developed, implemented and tested primarily in the SWAN wave model. So far, the new deepwater source terms for whitecapping were not fully tested in shallow environments. Similarly, the shallow water source terms were not yet tested in large inter-mediate depth areas Shell Global Solutions International B.V, Rijswijk, The Netherlands like the North Sea. As a first step in assessing the performance of these newly developed source terms, the source term balance and the effect of different physical settings on the prediction of wave heights and wave periods in the relatively shallow North Sea was analysed. The December 2013 storm was hindcast with a SWAN model implementation for the North Sea. Spectral wave boundary conditions were obtained from an Atlantic Ocean WAVEWATCH III model implementation and the model was driven by hourly CFSR wind fields. In the southern part of the North Sea, current and water level effects were included. The hindcast was performed with five different settings for whitecapping, viz. three Komen type whitecapping formulations, the saturation-based whitecapping by Van der Westhuysen et al. (2007) and the recently developed ST6 whitecapping as described by Zieger et al. (2015). Results of the wave hindcast were compared with buoy measurements at location K13 collected by the Dutch Ministry of Transport and Public Works. An analysis was made of the source term balance at three locations, the deep water location North Cormorant, the inter-mediate depth location K13 and at location Wielingen, a shallow water location close to the Dutch coast. The results indicate that at deep water the source terms for wind input, whitecapping and nonlinear four-wave interactions are of the same magnitude. At the inter-mediate depth location K13, bottom friction plays a significant role, whereas at the shallow water location Wielingen also depth-limited wave breaking becomes important.

In order to provide rapid access to reliable wave and wind climate information worldwide, a resource has been created combining: • a global offshore wind- and wave data-base, currently containing calibrated and validated spectral wave data from a wave hindcast model as well data from several satellite microwave sensors; • a simple but effective numerical model to predict nearshore wave conditions from the offshore spectra; • analysis tools to extract various climate parameters from the data such as scatter tables, extreme value analysis and persistency; • a web interface giving instantaneous access to the most commonly needed information. The resource is primarily intended for use in planning and design of operations typically requiring five years of data, but it an also be used for the design of certain structures, as there are now 16 years of significant wave height data from satellite radar altimeter available. This paper describes the components of the system and discusses their merits and limitations. We also present some results of the validation of the global satellite wave and wind data, of the global and regional wave model hindcasts, and of the nearshore wave transformation employed to obtain wave climate at sheltered or shallow-water sites.

Weather is becoming more extreme due to climate change (Pachauri and Meyer, 2014). Not only does violent weather increase the risk on loss of life, but higher ambient conditions increase the cost of operations and maintenance. At the same time the travel costs of offshore operations are rising as deep-water projects and wind parks are placed further and further from shore. In addition, the Offshore Industry embraced digitalization strategies more broadly in the mid-2010s, driving the need for more flexible data access. For providers of metocean solutions, traditional capabilities supported by legacy model sourcing were clearly insufficient to meet the future requirements across the industry as well as the adjacent Offshore Renewables sector. At the same time the shipping industry is working on the bridge of the future. Vessel response algorithms require detailed information of the current and future conditions. An evaluation of the development and deployment of a new generation marine forecasting system is provided. From the onset, the objective was to develop a flexible, global, cloud-native metocean forecast and hindcast system that provides a significant leap in accuracy, near-shore capability, and accessibility. It should verify at least as good as its predecessor; despite that it preserves peaks and events unlike the previous system, and all metocean parameters must be consistent with one another. Once implemented, it would provide operational metocean forecasts with global coverage with minimum spatial resolution of 6 minutes (0.1deg).