February 2025
| Model | SWAN 41.31 |
| Forecast horizon | 7 days |
| Spatial resolution | 0.01 degree (~1 km) |
| Temporal resolution | 1 hourly |
| Region | 3E - 4.75E, 51.4N - 53.05N |
| Forcings | ECMWF winds, tidal currents, and Oceanum spectra |
| Update frequency | 12-hourly |
The Dutch Coast wave forecast dataset provides operational wave predictions across the Netherlands coastal waters, including the North Sea approaches, and the Dutch coastline (Figure 1). The domain covers the entire Dutch continental shelf from the Belgian border to the German Bight. Wave forecasts are produced using the SWAN (Simulating WAves Nearshore) third-generation spectral wave model, with a 7-day forecast horizon updated every 12 hours (00, 12 UTC).
Wind forcing is provided by ECMWF IFS Open Data global atmospheric model. Spectral boundary conditions are supplied by the Oceanum Western Europe ECMWF wave forecast. Tidal currents are prescribed from Oceanum’s Western Europe tidal constituents, enabling accurate representation of wave-current interactions in the shallow North Sea and Waddenzee. Bathymetry is derived from the GEBCO 2024 global bathymetric grid.
The modelling setup employs the ST6 source term parameterisations. Spectra are discretised into 36 directional bins and 32 frequency bins, covering a frequency range from 0.037 to 0.71 Hz with 10% logarithmic increments. The model features a regular grid with a 1 km (0.01 degree) resolution, capturing detailed nearshore wave transformation processes.
The dataset provides hourly forecast 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-forced partition and up to three swell partitions. Forecasts are archived for 30 days, and frequency-direction wave spectra are available at 456 sites distributed across the domain. Nowcast datasets are also available, constructed by retaining the most recent data from each forecast cycle to provide a continuous near-real-time historical record.
Figure 1. Mean significant wave height from the Dutch Coast ERA5 hindcast domain (used for forecast validation).
The wave model physics and calibration have been validated against satellite altimeter observations for the corresponding hindcast domain. Validation results are available through the Oceanum Hindcast Satellite Validation App, which provides density scatter plots, quantile comparisons, and statistical metrics for the Western Europe region.
Table 1. Data description.
| Field | Value |
|---|---|
| Title | Oceanum Dutch Coast wave forecast |
| Institution | Oceanum |
| Access | Oceanum Datamesh |
| Source | SWAN 41.31A |
| Source terms | ST6 |
| Forecast horizon | 7 days |
| Update frequency | 12-hourly (ECMWF) |
| Archive period | 30 days |
| Temporal resolution | 1 hourly |
| Spatial coverage | [3E, 51.4N, 4.75E, 53.05N] at 0.01 degree |
| Spectra output sites | 456 |
| Frequency discretisation | 32 frequencies between 0.037 - 0.71 Hz at 10% logarithmic increments |
| Direction resolution | 10 deg |
| Bathymetry | GEBCO 2024 Grid |
| Winds | ECMWF IFS |
| Currents | Oceanum Western Europe tidal constituents |
| Boundary | Oceanum Western Europe ECMWF wave forecast |
ECMWF-forced (12-hourly updates):
Nowcasts (continuous near-real-time archive):
Integrated wave parameters are stored hourly over the domain at the native model resolution. Table 2 describes the gridded output parameters.
Table 2. Gridded output parameters.
| Variable | Long Name | Units |
|---|---|---|
| depth | depth below sea surface | m |
| hs | significant height of wind and swell waves | m |
| hs_sea | significant height of wind waves | m |
| hs_sw | significant height of swell waves | m |
| tps | smooth relative peak wave period of wind and swell waves | s |
| tps_sea | smooth relative peak wave period of wind waves | s |
| tps_sw | smooth relative peak wave period of swell waves | s |
| dpm | mean direction at the spectral peak of wind and swell waves | degree |
| dpm_sea | mean direction at the spectral peak of wind waves | degree |
| dpm_sw | mean direction at the spectral peak of swell waves | degree |
| tm01 | mean wave period based on first moment | s |
| tm02 | mean wave period based on second moment | s |
| dspr | directional spreading | degree |
| fspr | frequency spreading | - |
| phs0 | significant wave height of partition 0 (wind-forced) | m |
| phs1 | significant wave height of partition 1 (swell) | m |
| phs2 | significant wave height of partition 2 (swell) | m |
| phs3 | significant wave height of partition 3 (swell) | m |
| ptp0 | peak period of partition 0 (wind-forced) | s |
| ptp1 | peak period of partition 1 (swell) | s |
| ptp2 | peak period of partition 2 (swell) | s |
| ptp3 | peak period of partition 3 (swell) | s |
| pdir0 | peak direction of partition 0 (wind-forced) | degree |
| pdir1 | peak direction of partition 1 (swell) | degree |
| pdir2 | peak direction of partition 2 (swell) | degree |
| pdir3 | peak direction of partition 3 (swell) | degree |
| xwnd | eastward component of wind velocity | m/s |
| ywnd | northward component of wind velocity | m/s |
| xcur | eastward component of tidal current velocity | m/s |
| ycur | northward component of tidal current velocity | m/s |
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