Prof. Thomas J. Duck leads the Atmospheric-Optics Laboratory, and is a Theme Leader in the Canadian Network for the Detection of Atmospheric Change (CANDAC).
Welcome to the Atmospheric-Optics Laboratory in Physics and Atmospheric Science at Dalhousie University. We design, build and operate lidars (laser radars) for remote sensing of atmospheric properties and composition. We have two active instruments: the Dalhousie Raman Lidar in Halifax, and the CANDAC RMR Lidar in the High Arctic at Eureka. Our research interests include climate processes, air quality, and space instrumentation. We contributed to the successful Phoenix Mars Scout mission of 2008.
Students and Postdoctoral fellows play key roles in our research programme. They are involved in lidar operations, data analysis, interpretation of measurements, and the publication of results (see our publications list). If you are interested in contributing to our activities, please review our lab opportunities and contact us.
Looking for measurement images and data? See here.
Arctic Climate Research
The Arctic has warmed steadily over the past 40 years in concert with the melting of the polar ice cap. Atmospheric temperatures are largely determined by the exchange of light radiation between the sun, ground and sky. Measurements are needed to fully understand what is happening, but are often not available in the Arctic due to the harsh conditions. A main objective of our research is to help address the historic lack of data from the polar regions.
Together with the Canadian Network for the Detection of Atmospheric Change and Environment Canada, we established the Polar Environment Atmospheric Research Laboratory (PEARL) in the High Arctic at Eureka, Nunavut (80°N, 86°W) to investigate climate processes and other problems. CANDAC built and installed a variety of lidars, radars, radiometers, spectrometers, and photometers for atmospheric measurements. Our contribution was the "CANDAC RMR Lidar" which obtains vertical profiles of temperature, water vapour concentration, and cloud and aerosol optical properties. The instrument is operated by remote control, and the data are used together with the other instruments and satellite measurements to form a comprehensive picture of the Arctic atmosphere. We have published numerous papers on Arctic climate and climate processes using data from CANDAC's instruments.
Air Quality Research
The Dalhousie Raman Lidar, locate in Halifax, Nova Scotia, is used to detect atmospheric particles, or aerosols. Aerosols are an important component of pollution, biomass burning from forest fires, and volcanic eruptions. Nova Scotia has relatively little industrial activity, and the majority of pollution events seen overhead can be tracked back to major centers in North America. In collaboration with Environment Canada's Air Quality Research group in Atlantic Canada, we are working to understand the chemical contribution of long-range transport, and to identify local effects. Our measurements are taken primarily in the summer months, and the laser beam emanating from our laboratory is a popular sight in Halifax.
Nove Scotia is often called the "tailpipe of North America" because the jet stream carries air from across North America over the province. Pollution from industrialized Eastern North America is frequently observed in our measurements, and the strongest pollution event in years was observed during the summer of 2009 . During the summer of 2007, we identified plumes from large forest fires in Quebec, Northwest Territories, Utah, Idaho, and Mongolia. The plumes can reach incredible heights -- up to 15 km altitude. Plumes for volcanic eruptions can reach even higher, and the 2008 eruption of Mt. Kasatochi in the Aleutian Island of Alaska deposited aerosols near 18 km in altitude above Halifax.
In summer 2011 we operated the Dalhousie Ground Station as part of the international BORTAS measurements campaign that studied the chemistry of biomass burning plumes. The experiment featured fly-overs of the British BAe-146 research aircraft, guided by the lidar measurements.
Measurements and data files from the Dalhousie Raman Lidar can be found here.
We thank the following sponsors, without whose continued support our work would not be possible: Canadian Foundation for Innovation (CFI), Canadian Foundation for Climate and Atmospheric Science (CFCAS), National Sciences and Engineering Research Council of Canada (NSERC), Polar Continental Shelf Project (PCSP) of Natural Resources Canada (NRCAN), Environment Canada, and Nova Scotia Research Innovation Trust (NSRIT).
Prof. Thomas J. Duck
Department of Physics and Atmospheric Science,
Halifax, Nova Scotia, Canada, B3H 3J5