This group studies the Dynamics of the Mesosphere and Lower Thermosphere (MLT), or upper Middle Atmosphere (5 - 110 km). The observing instruments are a “Medium Frequency Radar” (MFR) at Saskatoon, which has operated continuously since 1979; and two MF radars, which were developed for the Canadian Network for Space Research (CNSR 1990-95). One is now located at Tromso, Norway on the EISCAT site (70N); the other is located at Platteville (near Boulder) as part of the CEDAR programme (40N). These provide data since 1987 and 2001 respectively. The development of CANDAC-PEARL at Eureka, Ellesmere Island (80N) www.candac.ca has provided a VHF meteor-scatter radar for winds and temperatures; this SKiYMET system was purchased from MARDOC Inc. Prof Manson is a Co-I for CANDAC [member of the Scientific Steering Committee], and along with Dr Meek “mentors” of the Eureka radar. We provide data to the CANDAC-PEARL Archive for international scientific community- collaborations; time sequences of preliminary data are available for perusal elsewhere at this web site. Our data archive runs from mid February 2006.
These MFRs provide echoes from 55/ 75 to 110 km during day/night hours, and are analyzed by spaced antenna and interferometric techniques to provide winds and wave data with periods from 10 min. to 10 years (solar cycle intervals). For SKiYMET, data are available from 82-97km. The atmospheric waves involved include gravity waves (GW) (10 min. to 15 h), tides (6-, 8-, 12- and 24-h), planetary waves (PW) (2 - 30d) and seasonal oscillations. The minimum period GWs from SKiYMET are 2 hrs. The four radars provide unique information on the spectral characteristics and wavelengths of these waves; the temporal variability and climatologies of the tides GW and PW; latitudinal and longitudinal variabilities, structures and modes; and the physical coupling mechanisms between these various scales of motion.
The research at Saskatoon has been and is coordinated with national and global-projects CANDAC-PEARL www.candac.ca , CAWSES (Climate and Weather of Sun-Earth System, 2004-08, www.bu.edu/CAWSES), CEDAR, PSMOS, and SRAMP of SCOSTEP (1998-02). Satellite data are used from a variety of Missions: TIMED-SABER, Odin-OSIRIS, Aura-MLS, ACE-MAESTRO. We are engaged/collaborate with the strong theoretical activity within the SPARC and MLT communities involving tidal and PW modelling, time-dependent gravity wave-tide-mean wind models, and also GCMs: Canadian GCM, CMAM-DAS, with integrated chemistry; MetO-DA [UK Met Office], TIME-GCM and GSWM. The US-based CEDAR programme (phase III) also provides a regional North American framework for MLT research.
The Canadian CANDAC-PEARL and its programmatic activity [see nearby in this site for thematic research and papers] is collaboratively linked with CAWSES, especially with the “Waves And Coupling Processes” [WACP] Theme at Eureka. Briefly: The Polar Regions are unique in the dynamics of the terrestrial atmosphere as they are in the vicinity of the Earth’s rotational axis. In the middle atmosphere they are the site of large scale ascent and descent which is thought to be driven by wave dissipation. Waves are the main agent coupling the various regions of the atmosphere. The purpose of the Waves and Coupling Processes theme is, for the polar middle atmosphere, to identify the large scale motions and constituent changes, investigate the nature of the wave phenomena and their effects and to link the wave phenomena to the large scale effects. The primary objectives include:
- the investigation of the wave signatures (gravity waves, tides and planetary waves) in the polar region.
- the identification of and characterization of the processes which couple the polar region to other regions of the atmosphere and which couple the various altitude regions (troposphere, stratosphere, mesosphere/lower thermosphere)
- the phenomena which occur as a result of this coupling and the waves themselves (sudden stratospheric warmings, constituent, wind and temperature variability, airglow signatures, noctilucent clouds, etc.)
The CAWSES Project “Atmospheric Wave Interactions with the Winter Polar Vortices (0-100km)” is within the Theme 3 of CAWSES ”Atmospheric Coupling Processes”, and its WG 3.1: Dynamical coupling and its role in the energy and momentum budget of the middle atmosphere.” Dr Manson is the co-ordinator of this project. The project description is in the CAWSES location nearby to this Introduction. The Winter Polar Vortices and associated science are part of both our CAWSES-project and our WACP CANDAC-PEARL research, so both locations will be of interest to the reader. Briefly: The extended title is….“Atmospheric Wave Interactions with the Winter Polar Vortices (0-100 km) from Observations and Modelling: Radiationally Unexpected Phenomena such as SSW (sudden stratospheric warmings), mesospheric inversion layers [MIL], equinoctial transitions, “Ozone Anomalies”, and the “Winter Anomaly” (D-region ionization) will be Investigated for CAWSES Winters Beginning in 2004/5”. A focus upon the radiationally unexpected phenomena in the atmosphere 0-110km (lower and middle atmosphere, MA) has enormous advantages. These events are so unique that they require extreme combinations of dynamics, chemistry and radiation to bring them into existence: stratospheric sudden warmings (or in their hemispheric absence, instabilities of the winter polar vortex) and their full atmospheric implications; the cold summer mesopause of extra-tropical latitudes; mesospheric thermal inversions; equinoctial middle atmospheric transitions and their asymmetry about the summer solstice; global couplings associated with El Nino and the Arctic/Antarctic Oscillations; global ozone morphology, including meridional wave-driven circulation patterns; the influences of the QBO and solar-induced modulations upon all of the above. The hemispheric differences in all of these phenomena must be considered ------- we are fortunate to live on ‘two-planets’. The studies must also be inclusive of all latitudes of the planet earth, as the equatorial regions have strong effects upon such phenomena, directly or indirectly, through dynamical processes. Their possible influences upon Climate Change processes must be strongly in our thinking and strategies.
The data from an earlier SCOSTEP program (1990 - 97), the Mesosphere Lower-Thermosphere Coupling Study (MLTCS) [that was convened by Dr. Manson], along with PSMOS data, have been analyzed as part of SRAMP and post-PSMOS activity. Studies of the MLT are concerned with all scales of waves and their interactions in the 80 - 150 km region; the effects of waves and winds upon the energy and momentum budgets; and related changes of the aeronomy (chemical and physical) of the region. The effects of energy inputs from the magnetosphere, the sun, and the lower atmosphere (gravity waves, tides, planetary waves) are also assessed. There were/are approximately 35 radars and 12 optical observatories, which were/are active in global campaigns; these enable the latitudinal, longitudinal and seasonal variations to be assessed. There is a list of publications nearby on this site….
The group at Saskatoon includes a senior scientist and research associate (Alan Manson, Chris Meek), two PDFs [Tatyana Chshyolkova, Xiaoyong Xu], one technician/engineer [Bill Marshall] and a graduate student [Ahmed Gahein] There are frequent opportunities to interact and network with other scientists in Canada, CANDAC-PEARL and in the international SCOSTEP community. The ground-based systems and their associated research in Canada are well integrated with CSA-Space Science Branch research www.space.ca involving satellite missions/systems, so that opportunities for collaboration projects are numerous. Graduating students (M.Sc., Ph.D.) and PDFs have a wide variety of careers available e.g. research-scientist or professor in a University or Research Institute; research scientist in a company specializing in 'Space Research', 'Remote Sensing' or 'Telecommunications and Information Technology'.