THE NERC MST RADAR FACILITY AT ABERYSTWYTH
Users of MST radar data are advised to state, in their publications, which version of the data products they have used (i.e. v0, v1, v2 or v3). Each signal processing scheme has (slightly) different data quality and reliability characteristics. It is important that readers can establish what these characteristics are and whether or not they are significant. The following paper can be referenced for this purpose:
- D. A. Hooper, J. Nash, T. Oakley, and M. Turp. Validation of a new signal processing scheme for the MST radar at Aberystwyth. Ann. Geophys., 26(11):3253-3268, 2008.
The paper contains details of the following:
- The sources of unwanted signal components observed by the Aberystwyth MST radar
- An overview of the v0 signal processing scheme
- An overview of algorithms used by the v3 signal processing scheme
- How the v1 and v2 schemes relate to the v0 and v3 schemes
- Various measures of horizontal (and to some extent vertical) wind data quality for the v0 and v3 schemes
- Geophysical causes of reduced wind data quality
- A probability distribution of the altitude of the tropopause above Aberystwyth
This paper describes a new signal processing scheme for the 46.5 MHz Doppler Beam Swinging wind-profiling radar at Aberystwyth, in the UK. Although the techniques used are similar to those already described in literature - i.e. the identification of multiple signal components within each spectrum and the use of radial- and time-continuity algorithms for quality-control purposes - it is shown that they must be adapted for the specific meteorological environment above Aberystwyth. In particular they need to take into account the three primary causes of unwanted signals: ground clutter, interference, and Rayleigh scatter from hydrometeors under stratiform precipitation conditions. Attention is also paid to the fact that short-period gravity-wave activity can lead to an invalidation of the fundamental assumption of the wind field remaining stationary over the temporal and spatial scales encompassed by a cycle of observation. Methods of identifying and accounting for such conditions are described. The random measurement error associated with horizontal wind components is estimated to be 3.0 - 4.0 m/s for single cycle data. This reduces to 2.0 - 3.0 m/s for data averaged over 30 minutes. The random measurement error associated with vertical wind components is estimated to be 0.2 - 0.3 m/s. This cannot be reduced by time-averaging as significant natural variability is expected over intervals of just a few minutes under conditions of short-period gravity-wave activity.