Ocean Wave Forecasting Research Articles

Waves and operational oceanography: Toward a coherent description of the upper ocean

The availability of new operational services for ocean circulation modeling presents a unique opportunity to rethink the operational forecasting of ocean waves and how circulation and waves may be combined to provide a better understanding of the upper ocean and enhanced services to society. The largescale oil spill caused by the wreck of the tanker Prestige off the Spanish coast in November 2002, and uncertainties on the fate of that pollution, illustrated the gaps in means of observations and knowledge of relevant processes.The idea of a coupled atmosphere‐wavesocean model was proposed by Klaus Hasselmann [Hasselmann, 1991], in the context of climate modeling. As waves are the “gearbox” between the atmosphere and the ocean, a detailed understanding of waves can significantly improve the parameterization of air‐sea fluxes and surface processes. Besides, Earth observation systems rely extensively on satellite remote sensing techniques for surface winds, temperature, sea level, ocean color, and sea ice, all affected by surface waves. Hasselmann viewed the future of wave modeling as the development of this central gearbox of a general Earth observation and monitoring system, providing fluxes between ocean and atmosphere in a way consistent with satellite observations. This vision, though slow to materialize, is highly relevant for short‐term forecasting in the coastal ocean.

Intercomparison of the Performance of Operational Ocean Wave Forecasting Systems with Buoy Data

The monthly exchange of ocean wave model data has successfully been taking place among five operational weather centers. The data are compared with observations obtained from moored buoys and platforms. The analysis of 3 yr of data has helped to quantify the global and regional skills, strengths, and weaknesses of the different ocean wave forecasting systems. Since the quality of ocean wave forecasts is intrinsically linked to the quality of the forcing wind fields, it is not surprising to find that the center with the lowest wind speed errors also has the lowest wave height errors. The benefit of using a third-generation Wave Model (WAM), for example, is not so tangible in terms of wave height statistics but it is definitively evident in terms of peak periods. Even though WAM has proved to be well suited for global wave forecasting, it is also clear that research is still needed to reduce the model tendency to underpredict some storms when it is forced by operational global wind fields. It appeared that assimilating altimeter wave heights has a positive impact on the model performance. It is also argued that the height of the wind speed observations should be taken into account when assimilating the data or simply when evaluating model performance since it might otherwise introduce a systematic negative bias into the analysis. Last, this exchange of data should continue and possibly extend to other forecasting centers as a tool for model developers but also as a continuous reference for marine forecasters.

Teaching ocean wave forecasting using computer-generated visualization and animation—Part 2: swell forecasting

This paper, the second of a two-part series, introduces undergraduate students to ocean wave forecasting using interactive computer-generated visualization and animation. Verbal descriptions and two-dimensional illustrations are often insufficient for student comprehension. Fortunately, the introduction of computers in the geosciences provides a tool for addressing this problem. Computer-generated visualization and animation, accompanied by oral explanation, have been shown to be a pedagogical improvement to more traditional methods of instruction. Cartographic science and other disciplines using geographical information systems have been especially aggressive in pioneering the use of visualization and animation, whereas oceanography has not. This paper will focus on the teaching of ocean swell wave forecasting, often considered a difficult oceanographic topic due to the mathematics and physics required, as well as its interdependence on time and space. Several MATLAB ® software programs are described and offered to visualize and animate group speed, frequency dispersion, angular dispersion, propagation, and wave height forecasting of deep water ocean swell waves. Teachers may use these interactive visualizations and animations without requiring an extensive background in computer programming.

Examination of the Impact of a Coupled Atmospheric and Ocean Wave System. Part II: Ocean Wave Aspects

A coupled atmospheric and ocean wave system has been developed to study the impact of changes of surface roughness length induced by ocean waves. A two-way coupling between a mesoscale atmospheric model, MC2, and an oceanic wave model, a regional version of WAM Cycle-4, was designed to ensure consistency in the treatment of the atmospheric boundary layer parameterizations between the two models. Two different approaches, based on the wave age of Smith et al. and the wave-induced stress of Janssen, are used to compute a coupling parameter, called the Charnock parameter, expressed as the nondimensional surface roughness length. The coupling between the two models is accomplished by the use of this parameter, which is a function of sea state, instead of the constant value obtained from empirical studies using the well-known Charnock relation. The impacts on the atmospheric forecasts are discussed in Part I. In Part II, the ocean wave forecasts resulting from this two-way coupling are discussed for four different real cases. The two approaches are evaluated by comparing ocean wave model outputs obtained from the coupled and uncoupled systems against buoy observations. The coupling has some beneficial impact, especially in areas of extreme sea states. The significant wave heights are reduced in the coupled runs and generally show better agreement with the buoy observations. The impact of the coupling also exhibits some dependence on the intensity of the cyclone development, with larger changes occurring in the case of rapidly deepening storms.

Assimilation of ERS SAR wave spectra in an operational wave model

Inverted wave spectra from ERS‐1 synthetic aperture radar (SAR) image and wave mode products have been assimilated in the operational wave model for the ocean wave forecast service at the Norwegian Meteorological Institute. Elements of the operational system are explained briefly, and the impact of including the SAR wave data in the operational wave model runs is shown both for individual cases and as overall statistics. Although individual cases clearly show that the satellite observations are able to influence the forecast in a generally positive way, the average improvement is minor for the areas covered by the wave model. Reasons for this are the intermittency of the data, on the average small differences between inverted SAR and model first‐guess wave spectra, and to some extent, limitations in the analysis method.

Development and Practical Use of Ocean Wave Forecasting System by Spectrum Method for Construction Management of Harbor

Development and Practical Use of Ocean Wave Forecasting System by Spectrum Method for Construction Management of Harbor

Measuring ocean waves from Space: 1978 to 1988

Abstract Global estimates of directional ocean wave spectra from space can help to spur improvements in the accuracy of existing ocean wave forecasts. The results of three ocean wave experiments conducted since 1978 indicate that a low altitude (∼300km) free-flying SAR could accurately monitor the performance of global wave models, and thus could help to assess the impact of both scatterometer-aided wind fields and improved wave model physics. The first opportunity to demonstrate such a potential should occur around the mid-1990s, when the European ERS scatterometer and the US Shuttle Space Radar Laboratory should be operating simultaneously.

Tests on Some Programmed Numerical Wave Forecast Models

Abstract Numerical forecasting of wind-generated ocean waves by digital computer may be attempted using any of three fundamentally different ways of describing wave generation and decay: empirical significant wave, empirical spectral, and theoretical spectral. This paper describes four models, covering the three types, which have been programmed with a view to the adaptation of one or more into a numerical wave forecast system for the Australian region. Results from a simple test situation are presented, both for comparison purposes and as a check on the internal consistency of the model's generation and decay functions.

An experiment in numerical forecasting of deep-water ocean waves. (Abstract) : Baer, L., 1962. J. Geophys. Res., 67 (9): 3539–3540

An experiment in numerical forecasting of deep-water ocean waves. (Abstract) : Baer, L., 1962. J. Geophys. Res., 67 (9): 3539–3540