The Alert Monitoring & Research Station

Watching the World from Canada’s High Arctic

At the extreme northern tip of Canada is the Canadian Forces Station, Alert – where the Meteorological Service of Canada MSC has a scientific research station of world-wide importance. Alert is the northern-most observatory in the World Meteorological Organization’s Global Atmosphere Watch Network of stations that have been tracking the chemistry of the atmosphere on a global basis for several decades. Alert’s location (far away from industrial pollution sources, with no settlements within hundreds of kilometres) makes it the perfect place from which to monitor long-term changes in the chemistry of the Earth’s atmosphere.

Dr. Neil Trivett (on left), who founded the Alert Observatory in 1986, is shown here with former Environment Minister, Jean Charest (on right), briefing him on the various measurement programs at Alert.

At Alert, research scientists continuously measure the trends and variability of the atmospheric chemicals that are key to understanding how human activities are affecting the world’s atmosphere. These measurements include greenhouse gases, toxic air pollutants such as mercury, organic pesticides and fine particles, and others such as stratospheric ozone. Changes in these atmospheric constituents over time are indicators of phenomena such as global warming, ozone depletion and the insidious spread of persistent organic pollutants into remote regions.

During polar sunrise, Alert becomes a photochemical laboratory. Since it is located very near the geographic North Pole, Alert sees extended periods of darkness in winter and continuous sunlight in summer. This prolonged day-night cycle makes it a valuable place to carry out photochemistry experiments.

The pollutants, transported over long distances from southern latitudes, accumulate in the Arctic atmosphere during winter and then react in the first rays of sunlight in spring. The Polar Sunrise Experiments, designed to study this phenomenon, have attracted researchers from around the world and have resulted in significant scientific discoveries that have changed our understanding of chemical and physical processes in the atmosphere.

The ice camp at Alert, Nunavut during the 2000 Polar Sunrise Study focused on mercury processes and snow surface chemistry.

At Alert, scientists have discovered that:

Arctic haze in late winter and spring is due largely to sulphate aerosols arising from the long range transport of sulphur oxides from the former Soviet Union and Eastern Europe.
Tropospheric (surface level) ozone disappears at polar sunrise because oxides of bromine cause ozone depletion at the Earth’s surface.
Bromine compounds are also linked to mercury deposition from the atmosphere.
The snow surface is much more chemically reactive than previously assumed, making snow part of the pathway for toxic chemicals such as polychlorinated biphenyls (PCBs) and pesticides to accumulate in Arctic ecosystems.

Conducting research in the High Arctic is a very expensive endeavour that has its challenges. Nevertheless, Canadian researchers have made valuable discoveries here that have furthered our understanding of atmospheric processes that impact on human and ecosystem health.

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The increasing trend of carbon dioxide concentrations at Alert, Nunavut from 1975 to present (based on weekly flask samples).

"Alert is the most northerly station in the Global Atmosphere Watch network of the WMO, and is critical in detecting global change. Monitoring efforts at Alert have anchored numerous international collaborative research studies of stratospheric ozone depletion, Arctic haze and the depletion of elemental mercury and tropospheric ozone at Polar Sunrise."
Leonard A. Barrie Chief
Environment Div.
World Meteorological Organization, Switzerland

Meteorological Service of Canada - Environment Canada - Government of Canada

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