Brewer Spectrophotometers on the roof of the Environment Canada building, Toronto
Canadian ozone research had its start in the 1930s with studies on the temperature structure of the stratosphere. In 1957, ARQX began taking daily ground-based measurements at two stations, to examine the thickness of the ozone layer. At that time Dobson instruments were being used. Currently ARQX operates a network of 12 sites measuring total column ozone. In the 1980s, ARQX developed the Automated Brewer Ozone Spectrophotometer (collectively referred to as the “Brewer”) and installed it in the ground-based monitoring network. The Brewer is now operated in over 40 countries.
The Brewer Spectrophotometer is used in the Canadian stratospheric ozone and UV monitoring program, with 12 sites established in Canada that routinely collect and process data on a daily basis. The instruments measure total ozone and spectral UV irradiation (290-325 nm) every 10-20 minutes during the daytime. They can also measure ozone using the light of a full moon when the sky is clear; this is useful in the Arctic winter. The information derived from the Brewer network is used for ozone and UV index forecasting, trend analysis and ongoing scientific research. Brewers can be adapted to measure other components of the atmosphere, such as nitrogen dioxide and aerosols.
Former Canadian Minister of the Environment John Baird launches an ozonesonde for a photo-op outside the Environment Canada Biosphère, Montreal, 16 September 2007.
(Photo by Tom Mathews)
ARQX with the cooperation of the Canadian Upper Air Network launches ozonesondes from ten locations across Canada on a roughly weekly basis. This is usually done every Wednesday but more frequently during periods of increased interest or special projects. Three of the stations are in the Canadian Arctic at Alert and Eureka on Ellesmere Island and Resolute, Nunavut. The other seven stations are at Goose Bay Labrador, Stony Plain Alberta, Kelowna British Columbia, Bratt’s Lake south of Regina Saskatchewan, Egbert Ontario, Yarmouth Nova Scotia and Churchill Manitoba. The data is available in graphical form here and is updated weekly.
Besides providing long term data for the ozone assessment community, the ARQX ozonesonde program is also involved with several national and international projects. A few of the latest ones are the Match program with the Alfred Wegner Institute in Potsdam Germany, and the MANTRA Nitrogen trend project.
In cooperation with the World Ozone and UV Radiation Data Centre (WOUDC), and other agencies, ARQX is engaged in a program to produce an map archive of ozone over Canada, the Northern Hemisphere, the Southern Hemisphere, and the globe. Maps are computed from a blend of sources or individual sources. Because data becomes available with a delay which can be from a few minutes to a few weeks, the maps are updated several times. They are made available the same day, or “recent” (a day or two old), or in the archive.