February 2025
| Model | SWAN 41.31 |
| Forecast horizon | 7 days |
| Spatial resolution | 0.05 degree (~5 km) |
| Temporal resolution | 1 hourly |
| Region | 77.5W - 63W, 35.5N - 46N |
| Forcings | ECMWF winds, tidal currents, and Oceanum spectra |
| Update frequency | 12-hourly |
The US East Coast wave forecast dataset provides operational wave predictions across the northeastern United States Atlantic seaboard, from Cape Hatteras to the Gulf of Maine (Figure 1). The domain encompasses the coastal waters of North Carolina, Virginia, Maryland, Delaware, New Jersey, New York, Connecticut, Rhode Island, Massachusetts, New Hampshire, and Maine. 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 Global WW3 wave model forced with ECMWF winds. Tidal currents are prescribed from Oceanum’s tidal constituents, enabling accurate representation of wave-current interactions in the Gulf Stream region and coastal embayments. Bathymetry is derived from the GEBCO 2023 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 5 km (0.05 degree) resolution, capturing the complex wave climate influenced by Atlantic hurricanes, nor’easters, and Gulf Stream interactions.
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 1105 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 US East Coast hindcast domain (used for forecast validation). The locations of 2D spectra hourly output are shown by the black dots.
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 US East Coast region.
Table 1. Data description.
| Field | Value |
|---|---|
| Title | Oceanum US East 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 | [77.5W, 35.5N, 63W, 46N] at 0.05 degree |
| Spectra output sites | 1105 |
| Frequency discretisation | 32 frequencies between 0.037 - 0.71 Hz at 10% logarithmic increments |
| Direction resolution | 10 deg |
| Bathymetry | GEBCO 2023 Grid |
| Winds | ECMWF IFS |
| Currents | Oceanum tidal constituents |
| Boundary | Oceanum Global WW3 wave forecast (ECMWF forced) |
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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