The University of Bath have operated a number of meteor radars in the northern and southern hemisphere since around 1999. These commercially produced Skiymet meteor radars are all-sky VHF (Very High Frequency) meteor radar systems. The various instruments have been operated by the University of Bath from October 1999 to present - albeit with some gaps in the data coverage. These were collected in support of a number of research projects - see linked Project records for further details.
The Skiymet radar detects radio scatter from the ionised trails of individual meteors drifting with the winds of the upper mesosphere, mesopause and lower thermosphere. A low-gain transmitter antenna is used to provide broad illumination of the sky. An array of five receiver antennas act as an interferometer to determine the azimuth and zenith angles of individual meteor echoes. Doppler measurements from each meteor determine the radial drift velocity and the meteor is assumed to be a passive tracer of atmospheric flow. The radar typically detects of order a few thousand meteors per day. These observations can be used to determine zonal and meridional winds in the mesosphere, mesopause and lower thermosphere at heights of about 80 – 100 km and with height and time resolutions of ~ 3 km and 2 hours.
The radar produces daily “meteor position data” data files (mpd files) recording the details of each individual meteor echo. In normal operation a few thousand individual meteors are detected per day. The key data parameters recorded for each meteor echo include:
1. Date and time of the meteor detection
2. Range to the meteor echo point
3. Height of the meteor echo above the ground
4. Radial drift velocity of the meteor echo and its uncertainty
5. Zenith and azimuth angles of the meteor echo
6. Ambiguity levels in the determined zenith and azimuth angles
7. Decay time of the meteor echo
8. Meteor echo power and S/N ratio
Recordings are made for each individual meteor detected allowing measurements of zonal and meridional wind speeds in the mesosphere and lower thermosphere to be obtained. Meteor count rates vary diurnally and with season, but are usually up to a few thousand meteors per day.