Atmospheric Dynamics Group Prof Alan Manson, Dr. Chris Meek.
This group studies the Dynamics of the Mesosphere and Lower Thermosphere (MLT), or upper Middle Atmosphere ( 55 - 110 km). The observing instruments are a Medium Frequency (MF) radar 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 located at Tromso, Norway on the EISCAT site; the other will be located in the U.S.A. with complementary CEDAR systems.
These radars provide echoes from 55/ 75 to 110 km during day/night hours, and are analyzed by spaced antenna and interferometer techniques to provide wind and wave data with periods from 10 min. to 10 years (solar cycle intervals). The waves involved include gravity waves (10 min. to 15 h), tides (6 -, 8 -, 12 -, 24h), planetary waves (2 - 30d) and seasonal oscillations. The three radars provide unique data on the phase velocities and wavelengths of these waves; the causes of temporal variability of the "tides"; and the physical coupling mechanisms between these various scales of motion. There are also optical instruments at Saskatoon and Calgary for more detailed studies of gravity waves eg., FPI, all- sky imaging photometer.
The research at Saskatoon is also co-ordinated with national (CNSR) and global-projects (STEP of SCOSTEP, and CEDAR) which include the UARS satellite (WINDII, HRDI) wind measuring systems. The principle one, the Mesosphere Lower-Thermosphere Coupling Study (MLTCS) is convened by Dr. Manson and is 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 upon aeronomy (chemical and physical) are studied globally. The effects of energy inputs from the magnetosphere, the sun, and the lower atmosphere (gravity waves, tides, planetary waves) are also assessed. There are approximately 35 radars and 12 optical observatories, which are active in global campaigns; these enable the latitudinal, longitudinal and seasonal variations to be assessed. There is strong theoretical activity within MLTCS involving tidal modelling, time-dependent gravity wave-tide-mean wind models, and TIGCMs (at NCAR Boulder, UCL-Sheffield). The CNSR (1990-95) involved studies which were complimentary to MLTCS but on smaller and vital national/regional scales; apart from the prairie activity, there is now a major observatory in Ontario (London) with MF/VHF radars and a lidar. The US-based CEDAR programme now provides a regional North American framework for MLT research.
The group at Saskatoon includes one senior scientist and one research associate (Dr. A.H. Manson, Dr. C.E. Meek), one technician/engineer , a data clerk (archiving, analysis), and several graduate students. There are frequent opportunities to interact and network with other scientists in Canada, CEDAR and in the international MLTCS community.