Spatial Tracking of Numerical Wave Model Output Using a Spiral Search Algorithm

Numerical ocean wave models output a frequency-direction energy spectrum at each grid point in space and time over a defined domain (e.g. the Pacific Ocean). After identifying each wave component (wind-sea, young swell and mature swell) using a spectral partitioning technique, a spiral search algorithm is used to identify the different wave systems, which are a cluster of wave-components propagating from a common origin on the ocean. This spiral search algorithm is being tested on output from two different wave models: the NOAA National Center for Environmental Prediction (NCEP) WaveWatch III and the Delft near-shore wave model SWAN (simulating wave near shore). The tracking algorithm, prototyped in Matlab, spirals once through the entire domain to identify existing wave systems. A second loop then combines neighboring wave systems initially separated by land.