Space and Atmospheric Science
My research mainly concerns measurements of temperature and composition in the middle atmosphere. Specific areas of expertise include:
My primary research tool is the Purple Crow Lidar (PCL; http://pcl.physics.uwo.ca), which measures temperature and composition of the Earth's atmosphere from the surface to 110 km altitude. The PCL is able to make these measurements at unprecedented accuracy by using a 2.65 m diameter liquid mirror telescope. The liquid mirror is a Canadian technology which allows large mirrors to be built at a fraction of the cost of traditional glass mirrors. Our expertise in these mirrors is due to our longstanding collaboration with Professor E. Borra’s group at the Université Laval, world leaders in this technology.
The long-term objectives of this research program are to search for atmospheric change and to help improve weather forecasting. Temperature change in the middle atmosphere is not directly affected by land, cities or oceans like surface temperature measurements, and in this region of the atmosphere surface heating corresponds to cooling (due to increased radiation of heat from CO2). The PCL measures water vapor composition change will be measured at both middle and high latitudes. In the middle atmosphere water vapor is an important part of the ozone cycle. We also measure layers of smoke particles in the upper troposphere and stratosphere (> 10 km altitude) associated with distant forest fires, injected into the stratosphere via a process called pyroconvection. The smoke particles can travel great distances, and affect both ozone concentration and temperature. With the number and severity of forest fires increasing, forest fires play a more complex role in global warming than anticipated, and we are trying to understand these effects.
The PCL also measures disturbances in the air density similar to waves on the surface of a lake called gravity waves. These waves break like ocean waves on a beach, primarily at altitudes above 50 km. Remarkably, even waves that break 100 km above the surface play an important role in determining the behaviour of weather systems which affect us on the surface. Furthermore, the gravity waves alter composition and thus affect ozone.
I am currently the Instrument Mentor for a stratospheric ozone lidar located at the Polar Environment Research Laboratory (PEARL) in Eureka, Nunavut. This site is only 1100 km from the North Pole and is part of the Canadian Network for the Detection of Atmospheric Change (CANDAC, http://www.candac.ca). Some of my students visit PEARL in the middle of the Arctic Night to make measurements. Maybe you want to join them!
I have developed courses at The University of Western Ontario in both atmospheric sciences (e.g. Physics 2070 for non-scientists and Physics 2700 for physics students) and the science of the sporting environment (Physics 2065). The sports course, intended for non-science students, is unique as it focusses on the effect of the land, air and water on an athlete’s performance using examples from activities including cycling, skating, athletics and swimming. A text for the course is currently in preparation.