The Natural Environment Research Council (NERC) Mesosphere-Stratosphere-Troposphere (MST) Radar is operated by the Science and Technology Facilities Council at the Radar Facility's (MSTRF's) site in Capel Dewi, near Aberystwyth, Mid-Wales. The 46.5 MHz pulsed Doppler radar is used primarily for making atmospheric observations over the approximate altitude range 2 - 20 km, i.e. over most of the troposphere and the lower stratosphere - hence the term "ST-mode". Additional observations are made over the approximate altitude range 56 - 96 km, i.e. covering the mesosphere - hence the term "M-mode" (see related dataset).

The instrument has been in operation, using the Dopppler Beam Swinging technique (see linked documentation for further details), since late 1989. It was intially operated on a campaign basis, but switched to quasi-continuous observations (i.e. close to 24-7 operation) in late 1997.

This dataset includes radial data products, i.e. range profiles along each beam pointing direction, and the "Cartesian" data products that are derived from them in the form of altitude profiles. The latter are used for most purposes. Data products are derived from the version 3 processing scheme, which supersedes earlier versions. Further details can be found via the linked documentation. Radial data products include:

signal power (relates to atmospheric structure)

radial velocity (relates to wind speed along the beam pointing direction)

spectral width (relates to turbulence intensity)

Cartesian data products include:

horizontal wind components (zonal and meridional)

vertical wind velocity

vertical beam signal power

tropopause altitude

vertical beam spectral width

radar return aspect sensitivity

Note - some files are released marked as '-suspect'. These have been released to permit early access to the data where the majority of data are known to pass quality control, but a small, limited part of the data have been identified as being 'suspect'. An internal remark about the suspect data may be found within the file's metadata 'comments' attribute.