Progress in Operational Wave Forecasting

Abstract

Progress in operational sea state forecasting is discussed in the context of the energy balance equation. This fundamental law describes the evolution of the wave spectrum due to adiabatic processes such as advection and refraction and due to physical processes such as generation of waves by wind, nonlinear interactions and wave dissipation. Progress in wave prediction is illustrated by means of a verification of operational wave height forecasts against wave height observations from buoys over the last 25 years of operational practice. Verification of modelled spectra against observed spectra by buoys is shown as well.

At the moment a number of weather forecasting centres spend a considerable amount of effort in the development of a fully comprehensive coupled atmosphere, ocean-wave, ocean circulation, sea-ice model. Central in the coupling of atmosphere and ocean in the ECMWF earth system model (see e.g. [1]) are the ocean waves that determine the momentum and energy transfer across the sea surface. In this paper we therefore concentrate of the sea-state dependence of the momentum (and heat) fluxes by studying in some detail the wind input source function of the energy balance equation. The importance of the strong coupling between wind and waves is illustrated by means of impact studies.