Wave Spectra

The Wave Spectra API provides full spectra 7-day forecast from the Sofar Operational WaveWatch III Model.

Operational Wave Spectra Forecast

GET https://api.sofarocean.com/api/op-wave-spectra/:lat/:lon

This endpoint returns a list of locations you have access to, or retrieves NetCDF data for a target location.

Path Parameters

Name	Type	Description
lat	number	latitude of location in decimal degrees. Must be 0.5º resolution.
lon	number	longitude of location in decimal degrees. Must be 0.5º resolution.

200 Example response of the list request, with lat and lon path parameters excluded.

{
    "status": "success",
    "data": [
        {
            "latitude": 34.5,
            "longitude": 200.0,
            "url": "https://api.sofarocean.com/api/op-wave-spectra/34.5/200"
        }
    ]
}

Example List Request

curl https://api.sofarocean.com/api/op-wave-spectra -H 'token: YOUR_API_TOKEN'

Example Data File Request

Content-Type: application/octet-stream Content-Disposition: attachment; filename="34.50_200.00_2019-12-19T12:00:00Z_data.netcdf"

curl https://api.sofarocean.com/api/op-wave-spectra/34.5/200 -H 'token: YOUR_API_TOKEN' -J -O

Spectral File Description

A Sofar Spectral File contains the variance density spectrum at a single grid point of the Sofar global wave model at an hourly resolution for the duration of the forecast. The data is stored in NetCDF format, and the variables contained in each file are listed in Table 1. A detailed description of the variables is given below.

Variable Name	Shape	Type	Units
directions	( Nd , )	float	Degrees
frequencies	( Nf , )	float	Hertz
time	( Nt , )	integer	Seconds
latitude	( 1 , )	float	Decimal degrees
longitude	( 1, )	float	Decimal degrees
depth	( 1, )	float	Meters
frequency direction spectrum	( Nt , Nd , Nf )	float	Meters2/Hertz/Degree

Table 1: The shape column indicates the shape of the array containing the variable, with Nt denoting the number of entries in time, Nf the number of frequencies and Nd the number of directions.

Directions

The direction vector contains the model directions at which the spectrum is stored. The directions are stored as a single vector of Nd=36 entries. Directions are measured counterclockwise from East. Each direction is given in degrees and indicates the direction the waves are traveling in. The directional grid has a constant resolution of 10 degrees ranging between [0,360].

Frequencies

The frequency vector contains the model frequencies at which the spectrum is stored. The frequencies are stored as a single vector of Nf=36 entries. Frequencies are measured in Hertz. The frequencies are defined on a logarithmic grid (1.1 growth factor) with minimum frequency f=0.035 Hz and maximum frequency f=0.98 Hz.

Time

The time vector denotes the time of the spectral entries. Time is denoted in Unix Epoch time, i.e. as seconds elapsed since Jan 1, 1970 (UTC). The time vector will be different lengths depending on the forecast initialization time. The first time denotes the initialization of the forecast.

Latitude, Longitude

The latitude and longitude are denoted in decimal degrees and indicate the location of the model grid point where the spectra were output.

Depth

Depth denotes the depth in meters at the location considered.

Frequency Direction Spectrum

The frequency direction spectrum contains the variance density as a function of time, direction, and frequency. Spectra are stored as a three-dimensional array where the first dimension is time, the second dimension is direction, and the third is frequency. Entries are stored as density values with units m2/Hz/deg.