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Environment Canada

Select Ozone Maps from Archive

Select one or two map set(s) by type, date and hemisphere, from the archive:

First map set
Total Ozone
Deviation from normal
Start date


How many
Interval

Hemi-
sphere

North
South
Globe
Second map set
No map
Total Ozone
Deviation from normal
Start date


How many
Interval

Hemi-
sphere

North
South
Globe
Map size? 100% 75% 50% 33%
(Note: 100% is 1000 pixels wide by 726 high)

15 October 2017, Total ozone, North hem
The total ozone maps are based on ground-based measurements available from the World Ozone and Ultraviolet Radiation Data Centre. Preliminary near real-time data from ground-based observations were also used for the most recent maps. Total ozone values are given in Dobson Units. The numbers represent observations taken from ground stations situated at the bottom left corner of the number.

Maps of deviations represent total ozone deviations from the 1978-1988 level estimated using Total Ozone Mapping Spectrometer (TOMS) data for all areas except the Antarctic and from the pre-1980 level estimated using Dobson data over the Antarctic.

Over areas with poor data coverage adjustments are made according to TOMS on Nimbus-7, Meteor-3, ADEOS and Earth Probe satellites. Over the polar night area Dobson and Brewer moon observations and/or NOAA's TIROS Operational Vertical Sounder (TOVS) satellite data are used. TOVS data are also used when the more reliable TOMS data are not available. The mapping algorithm is similar to those used by the WMO Ozone Mapping Centre.

The day part of the “Start date” can specify a day (1 to 31), a mean over the entire month (1-end) or the mean of a “10-day” period during the month (1-10, 11-20 or 21-end, which might be 8 or 9 or 11 days). It must logically correspond to the unit of the “Interval”.


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