Abstract
We compare hourly averaged neutral winds derived from two meteor radars operating at 33.2 and 55 MHz to estimate the errors in these measurements. We then compare the meteor radar winds with those from a medium-frequency partial reflection radar operating at 1.94 MHz. These three radars are located at Davis Station, Antarctica. We then consider a middle-latitude 55 MHz meteor radar wind comparison with a 1.98 MHz medium-frequency partial reflection radar to determine how representative the Davis results are. At both sites, the medium-frequency radar winds are clearly underestimated, and the underestimation increases from 80 km to the maximum height of 98 km. Correction factors are suggested for these results.
Highlights
One of the oldest radar techniques for investigating the mesosphere lower thermosphere (MLT) region between 60 and 100 km uses medium frequencies (MF) and partial reflections (PR) from that height region to measure electron densities using the differential absorption experiment (DAE), to measure neutral winds, most commonly using spaced antennas (SA) for reception, together with the full correlation analysis (FCA), to measure turbulent strength using velocity variances, and to measure structure using variations in returned power with height
A unique comparison of winds measured between two colocated meteor radars along with comparisons between meteor radar wind observations and MF PR SA FCA radar winds has been presented
Access to the three systems permitted a reduction in the number of unknowns in the regression analysis and a further clarification and quantification of the statistical relationship between the winds measured using the meteor and MF radar techniques
Summary
One of the oldest radar techniques for investigating the mesosphere lower thermosphere (MLT) region between 60 and 100 km uses medium frequencies (MF) and partial reflections (PR) from that height region to measure electron densities using the differential absorption experiment (DAE) (see, e.g., Holdsworth et al 2002), to measure neutral winds, most commonly using spaced antennas (SA) for reception, together with the full correlation analysis (FCA) (see, e.g., Briggs 1984), to measure turbulent strength using velocity variances (see, e.g., Holdsworth et al 2001), and to measure structure using variations in returned power with height (see, e.g., Reid 1990). (6) In the 60–80 km height region, there are too few intercomparisons to reach a general statistical conclusion on the validity of the winds Given this general understanding, more recent intercomparisons have been for the purposes of calibrating MF PR results against meteor radars (e.g., Wilhelm et al 2017). The X-mode is affected more by absorption and group retardation in an ionized atmosphere in comparison with the O-mode (see, e.g., Tsutsumi and Aso 2005) Both modes of operation provide wind estimates over most of the height range depending upon time of year, and the results from both modes can be combined to create a measurement average (see, e.g., Holdsworth et al 2001).
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