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Ann. Geophys., 15, 1111-1122, 1997
www.ann-geophys.net/15/1111/1997/
© European Geosciences Union 1997
Strengths and limitations of MST radar measurements of middle-atmosphere winds
W. K. Hocking
Department of Physics and Astronomy, University of Western Ontario, Canada
Abstract. Radars have been used successfully for many
years to measure atmospheric motions over a wide range of altitudes, from ground
level up to heights of several hundred kilometres into the ionosphere. In this
paper we particularly wish to concentrate on the accuracy of these measurements
for winds in the middle atmosphere (i.e. 10–100-km altitude). We begin by
briefly reviewing the literature relating to comparisons between radar methods
and other techniques. We demonstrate where the radar data are most and least
reliable and then, in parallel with a discussion about the basic principles of
the method, discuss why these different regimes have the different accuracies
and precisions they do. This discussion is used to highlight the strengths and
weaknesses of radar methods. Issues like radar volume, aspect sensitivity,
gravity wave effects and scatterer intermittency in producing wind biases, and
the degree by which the intermittent generation of scatterers at quasi-random
points in space could skew the radar measurements, are all considered. We also
investigate the possibility that MF radar techniques can be contaminated by
E-region scatter to heights as low as 92–95-km altitude (i.e. up to 8–10 km
below the ionospheric peak echo). Within all these comments, however, we also
recognize that radar methods still represent powerful techniques which have an
important future at all levels of the atmosphere.
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