Research Report 2009-2010 - College of Engineering - University of ...

space are strongly controlled by energetic particles and electric and magnetic fields
carried by the solar wind. Addition of PolarDARN radars provides an opportunity for
studies of the ionospheric and magnetospheric processes in the area called the “polar
cap” which surrounds the Earth’s magnetic pole, a region which had been unreachable
by the SuperDARN radars prior to the PolarDARN project. The main themes of recent
research include global-scale plasma convection patterns and their reconfiguration in
response to changes in the interplanetary magnetic field, plasma physics of ionospheric
irregularities, ionospheric signatures of energy transfer from the magnetosphere to the
ionosphere, and the physics of auroral substorms.
The Atmospheric Remote Sensing Group (ARSG) [Professors Degenstein, Bourassa
and Llewellyn] in the Institute has continued to develop techniques used to infer
atmospheric constituent information from observations of spectrally dispersed limb
scattered sunlight made with the Canadian built OSIRIS instrument. In the past year
members of the ARSG have focused their efforts on further development of the
SASKTRAN radiative transfer model and SaskMART, a Multiplicative Algebraic
Reconstruction Technique used to infer vertical number density profiles of ozone,
nitrogen dioxide and stratospheric sulphate aerosols directly from the OSIRIS radiance
measurements. In particular the ARSG has developed an ozone retrieval that
incorporates information from both the Chappuis and Hartley-Huggins absorption bands
to extend the upper altitude of the ozone measurements to 60 km. This technique has
received considerable attention from a team of NASA researchers planning an
operational instrument to monitor ozone for the foreseeable future. As well members of
the ARSG have advanced the development of techniques used to infer information
about stratospheric sulphate aerosols. The techniques now include a method to use the
OSIRIS radiance measurements to determine the size distribution parameters of these
particles as well as their number density. The ozone and aerosol data retrieved from
OSIRIS measurements are being used by other members of the ARSG to study long
term trends and the exchange processes that occur between the stratosphere and
troposphere. Other members of the group have continued to investigate mesospheric
phenomena with the OSIRIS data set. The areas of interest include: continued
investigation into the geographic distribution of Polar Mesospheric Clouds (PMC) as
well as the sizes and light scattering properties of the ice crystals that make up these
clouds; the measurement of true ground state (v = 0) hydroxyl from the OSIRIS
observations of resonantly scattered sunlight at 308 nm with the goal of retrieving the
water vapour concentrations throughout the sunlit mesosphere; the measurement of
mesospheric temperature profiles with Oxygen A Band emissions; and continued
investigation of the tertiary ozone peak and ozone depletion caused by solar proton
events. Together with the OSIRIS project, members of the ARSG are also involved in
other Canadian Space Agency satellite projects such as ACE-SCISAT, and a new
Physics and Engineering Physics – Research Report 2009-10 Page 129