Canada participates in the World Meteorological Organization's (WMO) Voluntary Observing Ships (VOS) program. This world-wide program involves 6700 ships from 55 countries that observe and report weather conditions when sailing. Canada has approximately 400 ships in the program. The Canadian VOS is maintained by Port Meteorological Officers (PMOs) at ports in St. John's, Newfoundland; Halifax, Nova Scotia; Montreal, Quebec; Burlington, Ontario and Vancouver, British Columbia. Visits are also made to ships recruited by other nations and to non-recruited ships.
The Kometik, a volunteer ship, tied up at Ocean Terminals in Halifax, NS.
Canada has two classes of observing ships: Selected and Auxiliary. The two classes differ in what parameters they report.
Selected ships are issued a complete set of tested meteorological instruments and report the following:
- Call Sign
- Date/Time
- Position - latitude and longitude
- Visibility - estimated or by use of radar
- True wind direction and speed - estimated by using the Beaufort Scale or measured using an anemometer
- Air temperature
- Dew point
- Sea level pressure - measured by a barometer
- 3 hour pressure change and tendency - measured by a barograph
- Present and past weather
- Cloud type, height and amount
- Ships course and speed
- Sea surface temperature - measured by using a sea bucket or by the ships engine water intake
- Wave information
- Ice Accretion
- Wet bulb temperature
- Ice type and concentration
Auxiliary ships may or may not be issued certified meteorological instruments and report the following:
- Call sign
- Date/time
- Position - Latitude and Longitude
- Visibility - estimated or by use of radar
- Height of lowest cloud
- True wind direction and speed - estimated by using the Beaufort Scale or measured using an anemometer
- Air temperature
- Sea level pressure - measured using a barometer
- Present and past weather
- Ships course and speed
- Wave information
- Ice accretion
- Ice type and concentration
Ships are requested to report weather four times a day at the main synoptic hours of 0000, 0600, 1200 and 1800 UTC. Ships navigating within 200 miles of the Canadian and US coastlines are requested to take supplementary observations at the intermediate synoptic hours of 0300, 0900, 1500 and 2100 UTC. In addition, a weather message is obligatory under Section 454 of the Canada Shipping Act when the ship encounters a tropical storm. The ship's officers are usually tasked with doing the observation.
Data from the Volunteer Ship Observing Network are critical for marine meteorologists to determine current conditions over the ocean where observations are scarce. Forecasters are able to improve the accuracy of their marine forecasts using these data, especially in the short-term. These data are essential input for numerical weather prediction models to produce weather forecast guidance over the ocean. They have also been incorporated into climatological applications.
Port Meteorological Officers (PMOs) try to visit ships in their program three to four times times a year. During these visits, meteorological instruments are calibrated or repaired, the meteorological log books are inspected, the ships' officers are trained (if required) and stationary and supplies are dispersed. Weather briefings are also provided as needed. PMOs also train observers at schools such as the Coast Guard college and nautical institutes.
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