Oceanum Global Wave Forecast

February 2025

Dataset description

The Oceanum global wave forecast provides 10-day predictions of wave conditions across all ocean basins (Figure 1). Wave fields are produced using the WAVEWATCH III (WW3) third-generation spectral wave model at 0.5-degree resolution. The forecast is run operationally with both GFS (updated 6-hourly) and ECMWF (updated 12-hourly) atmospheric forcing.

Wind forcing is provided by NOAA GFS at 0.25-degree resolution or ECMWF IFS at 0.25-degree resolution. Sea ice concentration is obtained from GFS for both model configurations. Bathymetry is derived from GEBCO 2020.

The modelling setup employs the ST4 source term parameterisations with calibrated parameters for global wave climate representation. Spectra are discretised into 24 directional bins and 31 frequency bins, covering a frequency range from 0.037 to 0.71 Hz with 10% logarithmic increments.

The dataset provides hourly estimates for key ocean wave parameters (Table 2) including spectral quantities integrated over the full spectrum and for spectral partitions. Partitions are defined from an 8-second split (sea/swell) and from the Watershed method, which identifies one wind-sea partition and up to four swell partitions. Frequency-direction wave spectra are available at strategically selected sites worldwide (black dots in Figure 1). Nowcast datasources are also provided, constructed from the most recent data in each forecast cycle to form continuous time series.

The global forecast is well suited for deep water wave predictions anywhere on the planet. A key application is providing directional spectral boundary conditions for downscaling regional and coastal wave models. The spectra output network is designed with variable density, ranging from 2 degrees in deep water to 0.5 degrees near coastlines, ensuring appropriate resolution for boundary forcing across diverse modelling applications. The spectral data is optimised for very fast access (seconds to a few minutes), enabling efficient operational workflows.

Figure 1. Mean significant wave height (Hs) over the global domain from the Oceanum ERA5 wave hindcast (1979-2020). Black dots indicate spectra output locations.

Validation

The global wave model configuration has been validated against satellite altimeter observations from multiple missions including Jason-2, Jason-3, Sentinel-3A, and Sentinel-3B. Validation statistics demonstrate excellent agreement with observed wave heights across all ocean basins. Detailed validation results are available in the hindcast specification document.

Interactive validation results are available through the Oceanum Validation App.

Data description

Table 1. Data description.

Linked Datamesh datasources

GFS Forced

• Oceanum global GFS wave forecast parameters
• Oceanum global GFS wave forecast spectra
• Oceanum global GFS wave nowcast parameters
• Oceanum global GFS wave nowcast spectra

ECMWF Forced

• Oceanum global ECMWF wave forecast parameters
• Oceanum global ECMWF wave forecast spectra
• Oceanum global ECMWF wave nowcast parameters
• Oceanum global ECMWF wave nowcast spectra

Related Hindcast

• Oceanum global ERA5 wave hindcast

Integrated parameters gridded output

Integrated wave parameters are stored 3-hourly over the domain at the native model resolution. Table 2 describes long names and units of key gridded output parameters.

Table 2. Gridded output parameters.

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