Ocean Wave Model – NOAA Wavewatch III Wind Modeling
Wind wave modeling uses computer simulation to estimate how the energy of wind waves is likely to evolve. As such, it aims to portray the sea state by making use of numerical techniques. From coastal engineering to maritime transport, wind wave models are beneficial for many different industries.
Early History of Wind Wave Modeling
Having the capacity to predict the sea state has always been desirable. And as the technology facilitating this developed, so did wind wave modeling. As a result, the evolution of wind wave models encompasses the following distinct types of them:
- Early empirical The earliest wind wave models relied on empirical observations, analyzing the relations between the current sea state and other factors. Devised manually, they would take note of the fetch, the anticipated wind conditions, and the wave propagation direction.
- Early theoretical By the 1960s, the basic theoretical work for using numerical techniques to devise wind wave models had appeared. Its spectral decomposition approach laid the foundation for the first numerical wind wave model of the North Atlantic in 1956.
- First-generation Focusing on only linear interrelations, first-generation wind wave models paid no attention to nonlinear types of wave interactions.
- Second-generation Appearing by the 1980s, second-generation wind wave models managed to describe nonlinear wave interactions in terms of parameters.
- Third-generation Third-generation wind wave models represent all the physics involved in the evolving of the sea state. And they are able to do so in two dimensions.
Wind Wave Modeling at Work
The process of devising wind wave models involves the following key steps:
- Input In theory, the data from satellite or buoy altimeters provides the input for analysis. In practice, most systems employ data from the preceding forecast instead of assimilating it.
- Representation Describing the sea state as a spectrum, physical equations depict various effects of how it evolves. The effects include wave propagation, shoaling, and refraction. Some models add bottom friction and swells dissipation.
- Output In the output, the significant wave height is estimated. It represents the mean wave height of the largest third of the waves. And includes the dominant wave propagation direction and period.
- Validation Wind wave model forecasts undergo further comparisons with the in situ altimetry data from buoys, satellites, oil platforms, and ships. This allows to identify the areas that need improvement.
Popular Wind Wave Models
The wind wave models below have become popular:
- WAVEWATCH III The model has a global domain and regional domains for oceanic basins in the Northern Hemisphere. Its effects include wave field refraction, nonlinear resonant interactions, updated ice coverage, and others.
- WAM Being the first third-generation model, it features two-dimensional wave spectrum with the unconstrained spectral shape. The model includes 36 wave propagation directions and 36 frequency bins.
CCHE2D-COAST Processes-based and integrated, this model simulates coastal processes in those coasts that have sophisticated shorelines. It comprises such effects as offshore-to-onshore wave deformation, wave set-up and set-down, morphological changes in seabed, and others.