The North Sea Andrea storm and numerical simulations

A coupling of a spectral wave model with a nonlinear phase-resolving model is used to reconstruct the evolution of wave statistics during a storm crossing the North Sea on 8–9 November 2007. During this storm a rogue wave (named the Andrea wave) was recorded at the Ekofisk field. The wave has characteristics comparable to the well-known New Year wave measured by Statoil at the Draupner platform 1 January 1995. Hindcast data of the storm at the nearest grid point to the Ekofisk field are here applied as input to calculate the evolution of random realizations of the sea surface and its statistical properties. Numerical simulations are carried out using the Euler equations with a higher-order spectral method (HOSM). Results are compared with some characteristics of the Andrea wave record measured by the down-looking lasers at Ekofisk

Wind generated rogue waves in an annular wave flume

We investigate experimentally the statistical properties of a wind-generated wave field and the spontaneous formation of rogue waves in an annular flume. Unlike many experiments on rogue waves, where waves are mechanically generated, here the wave field is forced naturally by wind as it is in the ocean. What is unique about the present experiment is that the annular geometry of the tank makes waves propagating circularly in an {\it unlimited-fetch} condition. Within this peculiar framework, we discuss the temporal evolution of the statistical properties of the surface elevation. We show that rogue waves and heavy-tail statistics may develop naturally during the growth of the waves just before the wave height reaches a stationary condition. Our results shed new light on the formation of rogue waves in a natural environment

Wave modelling - the state of the art

This paper is the product of the wave modelling community and it tries to make a picture of the present situation in this branch of science, exploring the previous and the most recent results and looking ahead towards the solution of the problems we presently face. Both theory and applications are considered. The many faces of the subject imply separate discussions. This is reflected into the single sections, seven of them, each dealing with a specific topic, the whole providing a broad and solid overview of the present state of the art. After an introduction framing the problem and the approach we followed, we deal in sequence with the following subjects: (Section) 2, generation by wind; 3, nonlinear interactions in deep water; 4, white-capping dissipation; 5, nonlinear interactions in shallow water; 6, dissipation at the sea bottom; 7, wave propagation; 8, numerics. The two final sections, 9 and 10, summarize the present situation from a general point of view and try to look at the future developments

Impact assessment for the improved four boundary conditions (at bed, free-surface, land-boundary and offshore-boundary) on coastal hydrodynamics and particulate transport

The FIELD_AC project aims at providing an improved operational service for coastal areas and at generating added value for shelf and regional scale predictions. Coastal-zone oceanographic predictions seldom appraise the land discharge as a boundary condition. River fluxes are sometimes considered, but neglecting their 3D character, while the "distributed" continental run-off is not taken into consideration. Moreover, many coastal scale processes, particularly those relevant in geographically restricted domains (coast with harbors or river mouth areas), are not well parametrized in present simulations.Work package 3 dedicated to Boundary Fluxes aims to establish and use the best possible boundary conditions for coastal water quality modelling. On this scale, all boundaries become important. For the land boundary side the needed products are distributed and point wise run-off both quantitatively and qualitatively. For the offshore boundary condition, 3D current, water quality field, and wave spectra will be used. For the atmospheric boundary, products from local scale meteorological models (wind, atmospheric pressure and rainfall) are needed. For the seabed, boundary information on sediment composition, bedforms and bathymetry and bio-geo-chemical parameters is essential.This report addresses the impact assessment for improvements in the four boundary conditions (boundary fluxes from land, free-surface boundary condition, seabed boundary condition and open boundary fluxes) on coastal hydrodynamics and particulate transport. The description of the improved four boundary conditions is followed by examples of concrete impact assessment of the theory into the Catalan coast, Liverpool Bay, German Bight and Gulf of Venice