Activate accessible linear format for this web page.
Environment Canada
Symbol of the Government of Canada

Common menu bar links

World Ozone Monitoring and Mapping

The Most Recent Full-Day Global Total Ozone Map:

Other ozone maps available on this Website:

Canada Maps:


The Ozone and UV monitoring section of the Experimental Studies Section of Environment Canada, in cooperation with its sister section, the World Ozone and UV Radiation Data Centre (WOUDC), is engaged in a program of mapping the ozone layer over the entire earth.

Current Ozone Map

Data sources

Data are obtained from

They can be seen in the archive of total ozone maps by source.

“All sources blended” is a smaller copy of the total ozone maps found in the Ozone map archive. It is built from a blend of the other maps. Satellite data have been smoothed.

“Ground-based data” are from instruments on the ground, Brewers, Dobsons, filter ozonometers, SAOZ instruments. New data are contributed by Environment Canada, the Russian Central Aerological Observatory, and by agencies in many other countries. Older data have been obtained from the World Ozone and Ultraviolet Radiation Data Centre (WOUDC). Data quality is best when taken on a sunny day, but techniques are available to measure ozone during cloudy days and sometimes at night using lunar light.

“TOMS satellite” is from NASA's Total Ozone Mapping Spectrometer (TOMS) on board the Earth Probe satellite. Data from the OMI instrument are also included here.

“TOVS satellite” is from NOAA's TIROS Operational Vertical Sounder (TOVS) on the NOAA polar-orbiting satellites. Its data is less reliable than TOMS data but TOVS can see ozone at night, in particular during the polar night.

“GOME satellite”. For the period 1995-2003, data is from the European Space Agency's Global Ozone Monitoring Experiment (GOME) on board the European Remote Sensing Satellite-2 (ERS-2). For the period from 2008, data is from the GOME-2 instrument on board MetOp-A (launched in October 2006) provided by the World Data Center for Remote Sensing of the Atmosphere .

“KNMI analysis” is based on the GOME Fast delivery service data (up to 2003), and data from the SCIAMACHY instrument on the Envisat satellite, interpreted by the TEMIS service (starting 2004), provided by the Royal Netherlands Meteorological Institute (KNMI).

“SMOBA analysis” is from NOAA's Stratosphere Monitoring Ozone Blended Analysis (SMOBA), which uses measurements from SBUV/2 (Solar backscatter ultraviolet instrument) equatorward of the polar night with TOVS ozone data blended from the terminator poleward.

“TOAST analysis” is from NOAA's Total Ozone Analysis using SBUV/2 and TOVS, which uses measurements from SBUV/2 and TOVS.

“NCEP” forecasts are issued daily by the National Centers for Environmental Prediction (NCEP) of the National Oceanographic and Atmospheric Administration (NOAA) in the USA, for every 6 hours from 0 to 120, at 0h UTC each day. These maps are a subset, representing every 24 hours from 12 to 108, i.e. for 12h UTC on days 0 to 4.

“KNMI” forecasts are issued daily by the Royal Netherlands Meteorological Institute (KNMI), representing every day from 0 to 4, at 12h UTC.

“Total Ozone” represents the total amount of ozone in a vertical column reaching from the earth's surface to the top of the atmosphere. Values are given in Dobson Units.

“Deviation from Normal” represents total ozone deviations from the 1978-1988 level estimated using TOMS data. Values are given in percent.

These maps are for purposes of illustration only. For any more detailed use of the data, please go to the original sources mentioned above.