Humidity and Fog Contained within the 3rd Edition (1957) of the Atlas of Canada is six maps that show the humidity and fog occurrences across Canada. Two maps on the top that show the mean mixing ratios for January and July, respectively. Mixing ratio is defined as the ratio of the mass of the water vapor to the mass of dry air in a unit volume. The two mixing ratio maps on this plate are based on observations taken at midnight, 6 a.m., noon, and 6 p.m. Greenwich Mean Time over the ten year period from 1941 to 1950 inclusive. Humidity data was obtained from the regular reading of artificially-ventilated dry and wet bulb thermometers housed in standard thermometer shelters. Knowing the dry bulb temperature and the difference in temperature between the dry and wet bulbs, it is possible to calculate the different measures of humidity. The remaining maps show the mean number of days with fog for each of winter, spring, summer and fall. Winter is considered as the months of December, January and February; spring as March, April and May; summer as June, July and August; and fall as September, October and November. Fog is defined as an obscurity in the surface layers of the atmosphere caused by water droplets in suspension in the air which reduce visibility. A day with fog is considered to be a day on which the visibility was lowered to less than five-eighths of a mile (approximately 1 km) by fog for some part of the day. 1957-01-01 2017-01-26 Natural Resources Canada NRCan.geogratis-geogratis.RNCan@canada.ca Nature and EnvironmentScience and Technologyclimateclimate archivesmeteorology Download the English JPG through HTTPJPG http://ftp.geogratis.gc.ca/pub/nrcan_rncan/raster/atlas_3_ed/eng/environment/climate/029.jpg Download the English PDF through HTTPPDF http://ftp.geogratis.gc.ca/pub/nrcan_rncan/raster/atlas_3_ed/eng/environment/climate/029.pdf Download the French JPG through HTTPJPG http://ftp.geogratis.gc.ca/pub/nrcan_rncan/raster/atlas_3_ed/fra/environment/climate/029.jpg Download the French PDF through HTTPPDF http://ftp.geogratis.gc.ca/pub/nrcan_rncan/raster/atlas_3_ed/fra/environment/climate/029.pdf

Humidity and Fog

Contained within the 3rd Edition (1957) of the Atlas of Canada is six maps that show the humidity and fog occurrences across Canada. Two maps on the top that show the mean mixing ratios for January and July, respectively. Mixing ratio is defined as the ratio of the mass of the water vapor to the mass of dry air in a unit volume. The two mixing ratio maps on this plate are based on observations taken at midnight, 6 a.m., noon, and 6 p.m. Greenwich Mean Time over the ten year period from 1941 to 1950 inclusive. Humidity data was obtained from the regular reading of artificially-ventilated dry and wet bulb thermometers housed in standard thermometer shelters. Knowing the dry bulb temperature and the difference in temperature between the dry and wet bulbs, it is possible to calculate the different measures of humidity. The remaining maps show the mean number of days with fog for each of winter, spring, summer and fall. Winter is considered as the months of December, January and February; spring as March, April and May; summer as June, July and August; and fall as September, October and November. Fog is defined as an obscurity in the surface layers of the atmosphere caused by water droplets in suspension in the air which reduce visibility. A day with fog is considered to be a day on which the visibility was lowered to less than five-eighths of a mile (approximately 1 km) by fog for some part of the day.

Resources

Resource Name Resource Type Format Language Links
Download the English JPG through HTTP Dataset JPG English
French
Access
Download the English PDF through HTTP Dataset PDF English
French
Access
Download the French JPG through HTTP Dataset JPG English
French
Access
Download the French PDF through HTTP Dataset PDF English
French
Access

Geographic Information

Spatial Feature