Numerical Data - RDWPS - GRIB2

The RDWPS produces wave forecasts for the major Canadian marine forecast regions using the third generation spectral wave model WAM. The model is forced by the 10 meters winds from the Regional or Global Deterministic Prediction System(s). 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).

North Atlantic

North Atlantic geographical grid coverage

Grid specifications

Table lists the values of various parameters of the North Atlantic RDWPS grid">
ni 654
nj 335
resolution 0.15 deg x 0.15deg
coordinate of first grid point 20.075° N
97.925° W ( Long 97.925W to 0.025E Lat 70.175N to 20.075N )

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

North Pacific

North Pacific geographical grid coverage

Grid specifications

Table lists the values of various parameters of the North Pacific GDWPS grid">
ni 161
nj 71
resolution 0.5 deg x 0.5 deg
coordinate of first grid point 25.00° N
200.00° W ( Long 200.0W to 120.0W Lat 60.00N to 25.0N)

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

Lake Superior:

Lake Superior geographical grid coverage

Grid specifications

Table lists the values of various parameters of the Lake Superior RDWPS grid">
ni 102
nj 49
resolution 0.05554 deg x 0.08187 deg
coordinate of first grid point 46.318° N
92.312° W (Long 92.312W to 84.043W Lat 48.984N to 46.318N)

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

Lake Huron:

Lake Huron geographical grid coverage

Grid specifications

Table lists the values of various parameters of the Lake Huron RDWPS grid">
ni 70
nj 63
resolution 0.05502 deg x 0.07819 deg
coordinate of first grid point 42.936° N
84.773° W (Long 84.773W to 79.378W Lat 46.347N to 42.936N)

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

Lake Erie:

Lake Erie geographical grid coverage

Grid specifications

Table lists the values of various parameters of the Lake Erie RDWPS grid">
ni 98
nj 35
resolution 0.05 deg x 0.05 deg
coordinate of first grid point 41.3° N
83.6° W ( Long 83.6W to 78.75W Lat 43.0N to 41.3N )

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

Lake Ontario:

Lake Ontario geographical grid coverage

Grid specifications

Table lists the values of various parameters of the Lake Ontario RDWPS grid">
ni 51
nj 19
resolution 0.05688 deg x 0.07553 deg
coordinate of first grid point 43.164° N
79.851° W (Long 79.851W to 76.074W Lat 44.188N to 43.164N)

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

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">
ni 331
nj 160
resolution 0.05 deg x 0.05 deg
coordinate of first grid point 44.075° N
70.925° W (Long 70.925W to 54.425W Lat 52.025N to 44.075N )

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

Arctic:

Arctic geographical grid coverage

Grid specifications

Table lists the values of various parameters of the Arctic RDWPS grid">
ni 151
nj 91
resolution 0.4 deg x 0.8 deg
coordinate of first grid point 49.0° N
165.0° W (Long 165.0W to 45.0W Lat 49.0N to 85.0N)

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.weatheroffice.gc.ca/model_wave/great_lakes/erie/grib2/HH/

http://dd.weatheroffice.gc.ca/model_wave/great_lakes/huron/grib2/HH/

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

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

http://dd.weatheroffice.gc.ca/model_wave/ocean/atlantic_north/grib2/HH/

http://dd.weatheroffice.gc.ca/model_wave/ocean/arctic/grib2/HH/

http://dd.weatheroffice.gc.ca/model_wave/ocean/pacific_north/grib2/HH/

http://dd.weatheroffice.gc.ca/model_wave/ocean/gulf_st_lawrence/grib2/HH/

where:

  • HH: model run start, in UTC [00,06,12,18]. For the pacific-north domain only; HH=[00 or 12]

File name nomenclature

The file names have the following nomenclature:
CMC_rdwps_domain_Variable_LevelType_level_latlondddxddd_YYYYMMDDHH_Phhh.grib2

where:

  • CMC: constant string indicating that the data is from the Canadian Meteorological Centre
  • rdwps: constant string indicating that the data is from the Regional Deterministic Wave Prediction System
  • domain: constant string indicating which domain that the data is from
  • Variable: Variable type included in this file.
  • LevelType: Level type.
  • Level: Level value.
  • latlon0.dx0.dd: constant string indicating that the projection used is lat/long at 0.dd x 0.dd degrees resolution
  • YYYYMMDD: Year, month and day of the beginning of the forecast.
  • HH: UTC run time [00,06,12,18]
  • Phhh: P is a constant character. hhh is the forecast hour [000,006,012,...,048/054]
  • grib2: constant string indicating the GRIB2 format is used

Example of file name:
CMC_rdwps_lake-ontario_WVPER_SFC_0_latlon0.05x0.08_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 wave period (WVPER) for Lake Ontario at the surface (SFC_0) on a lat/long grid at 0.05 degree x 0.08 degreee resolution for the forecast hour 042 (P042) in GRIB2 format (.grib2).

Levels

Levels that may be applicable to a given parameter are:

  • surface
  • fixed height above ground
  • mean sea level

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.
10/0/3 Significant height of combind wind waves and swell HTSGW SFC m
10/0/34 Peak wave period PKPER SFC m
0/3/1 Pressure
Reduced to Mean Sea Level		 PRMSL MSL Pa
10/0/7 Direction of swell waves SWDIR SFC degrees true
10/0/8 Significant height of swell waves SWELL SFC m
10/0/9 Mean period of swell waves SWPER SFC s
0/2/2 U-Component of Wind UGRD TGL (10m above ground) m/s
0/2/3 V-Component of Wind VGRD TGL (10m above ground) m/s
10/0/4 Direction of wind waves (from which) WVDIR SFC degrees true
10/0/5 Significant height of wind waves WVHGT SFC m
10/0/6 Mean period of wind waves WVPER SFC s