Numerical data from the RDWPS in GRIB2 format

Great Lakes

The Regional Deterministic Wave Prediction System (RDWPS) produces wave forecasts for the Great Lakes using the third generation spectral wave model WaveWatch III®. The model is forced by the 10 meters winds from the High Resolution Deterministic Prediction System (HRDPS). A sea ice analysis is used by the model to dampen or suppress wave growth in areas covered respectively with 25% to 75% and more than 75% ice.

The WW3 (Tolman and the WAVEWATCH III® Development Group 2014) is a third generation spectral wave prediction model that solves the evolution of the energy balance equation for the 2-D wave energy spectrum without any prior assumptions on the shape of the spectrum. The WW3 model has been implemented by a growing number of national operational forecasting centers over the last several years.

Gulf of Saint Lawrence

The Regional Deterministic Wave Prediction System (RDWPS) produces wave forecasts for the Gulf of Saint Lawrence using the third generation spectral wave model WAM. The model is forced by the 10 meters winds from the Regional Deterministic Prediction System. In addition, an analysis of sea ice is used by the model to suppress wave growth in areas covered with greater than 50% ice.

WAM (WAve Model) (WAMDI Group 1988, Komen et al. 1994) is a third generation spectral wave prediction model that solves the evolution of the energy balance equation for the 2-D wave energy spectrum without any prior assumptions on the shape of the spectrum. The WAM model has been operational in the international community since the early nineties after a long period of development under the WAMDIG (WAve Model Development and Implementation Group).

Lake Superior:

Lake Superior geographical grid coverage

Grid specifications

Table lists the values of various parameters of the Lake Superior RDWPS grid

Parameter Value
ni 658
nj 318
resolution 0.0090 deg x 0.0124 deg
coordinate of first grid point 46.2590° N
92.3116° W

Lake Huron and Michigan:

Lake Huron geographical grid coverage

Grid specifications

Table lists the values of various parameters of the Lake Huron and Michigan RDWPS grid

Parameter Value
ni 698
nj 573
resolution 0.0090 deg x 0.0124 deg
coordinate of first grid point 41.4260° N
88.1452° W

Lake Erie:

Lake Erie geographical grid coverage

Grid specifications

Table lists the values of various parameters of the Lake Erie RDWPS grid

Parameter Value
ni 398
nj 210
resolution 0.0090 deg x 0.0124 deg
coordinate of first grid point 41.2190° N
83.6068° W

Lake Ontario:

Lake Ontario geographical grid coverage

Grid specifications

Table lists the values of various parameters of the Lake Ontario RDWPS grid

Parameter Value
ni 348
nj 158
resolution 0.0090 deg x 0.0124 deg
coordinate of first grid point 43.0640° N
79.9736° W

Gulf of St Lawrence:

Gulf of St Lawrence geographical grid coverage

Grid specifications

Table lists the values of various parameters of the Gulf of St Lawrence RDWPS grid

Parameter Value
ni 331
nj 160
resolution 0.05 deg x 0.05 deg
coordinate of first grid point 44.075° N
70.925° W

There is also a formatted gzipped ASCII file containing geographical coordinates for each grid point.

Download

The data is available using the HTTP procotol and resides in a directory that is plainly accessible to a web browser. Visiting that directory with an interactive browser will yield a raw listing of links, each link being a downloadable GRIB2 file. In practice, we recommend writing your own script to automate the downloading of the desired data (using wget or equivalent). If you are unsure of how to proceed, you might like to take a look at our brief wget usage guide.

The data can be accessed at the following URLs:

http://dd.weather.gc.ca/model_wave/great_lakes/erie/grib2/HH/

http://dd.weather.gc.ca/model_wave/great_lakes/huron-michigan/grib2/HH/

http://dd.weather.gc.ca/model_wave/great_lakes/ontario/grib2/HH/

http://dd.weather.gc.ca/model_wave/great_lakes/superior/grib2/HH/

http://dd.weather.gc.ca/model_wave/ocean/gulf-st-lawrence/grib2/HH/

where:

File name nomenclature

The file names have the following nomenclature:
CMC_rdwps_domain_Variable_LevelType_level_latlondddxddd_YYYYMMDDHH_Phhh.grib2

where:

Example of file name:
CMC_rdwps_lake-ontario_HTSGW_SFC_0_latlon0.0090x0.0124_2012032106_P042.grib2

This file originates from the Canadian Meteorological Center (CMC) and contains the data of the Regional Deterministic Wave Prediction System. The data in the file start on March 21th 2012 at 06Z (2012032106). It contains the significant wave height (HTSGW) for Lake Ontario at the surface (SFC_0) on a lat/long grid at 0.0090 degree x 0.0124 degree resolution for the forecast hour 042 (P042) in GRIB2 format (.grib2).

Levels

Levels that may be applicable to a given parameter are:

Data in GRIB2 format

Available fields : parameter numbers and units

This table provides, for each GRIB2 parameter number: a short description, an alphabetical abbreviation, the levels available for the parameter, and measurement units.

GRIB2 discipline/
category/parameter number
Parameter
description
Abbreviation
Level Units

NOTES:

  1. u and v components of the wind vector are to be resolved relative to the defined grid, in the direction of increasing i and j coordinates.
10/0/2 Ice cover ICEC SFC_0 fraction
0/2/2 U-Component of Wind UGRD TGL_10 (10m above ground) m/s
0/2/3 V-Component of Wind VGRD TGL_10 (10m above ground) m/s
10/0/3 Significant height of combined wind waves and swell HTSGW SFC_0 m
10/0/4 Direction of wind waves (from which) WVDIR SFC_0 degrees true
10/0/5 Significant height of wind waves WVHGT SFC_0 m
10/0/6 Mean period of wind waves WVPER SFC_0 s
Great Lakes only
10/0/34 Peak wave period PWPER SFC_0 s
10/0/28 Mean zero-crossing wave period MZWPER SFC_0 s
10/0/7 Direction of primary swell SWDIR SFC_0 degrees true
10/0/8 Significant height of primary swell SWELL SFC_0 m
10/0/9 Peak period of primary swell SWPER SFC_0 s
Gulf of Saint Lawrence only
10/0/34 Peak wave period PKPER TGL_0 (0m above ground) s
0/3/1 Pressure Reduced to Mean Sea Level PRMSL MSL_0 Pa
10/0/7 Direction of swell waves SWDIR SFC_0 degrees true
10/0/8 Significant height of swell waves SWELL SFC_0 m
10/0/9 Mean period of swell waves SWPER SFC_0 s

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