Comparison of VHF Doppler beam swinging and spaced antenna observations with the MU radar: First results

Authors

  • J. S. Van Baelen,

  • T. Tsuda,

  • A. D. Richmond,

  • S. K. Avery,

  • S. Kato,

  • S. Fukao,

  • M. Yamamoto


Abstract

We present a comparison between wind measurements in the 5–21 km altitude range over the middle and upper atmosphere (MU) radar obtained by two different techniques: Doppler beam swinging (DBS) and spaced antenna (SA). The SA data are analyzed by full correlation analysis (FCA) to extract the apparent and true velocities. The period analyzed, December 14–18, 1988, had strong zonal winds that often exceeded 80 m/s at around 11 km altitude and also had substantial (> 1 m/s) vertical winds that existed over extended regions of height and time. It is essential to account properly for the vertical wind when extracting the horizontal winds from the oblique DBS beams, but no obvious influence of the vertical velocity on the FCA is detected. In different altitude regions of the atmosphere (below and above the jet stream peak and above 17.7 km), the DBS amplitude alternately agrees better with the true or the apparent velocity obtained by the FCA method. The directions of all three wind estimations agree well, although the apparent direction displays more variability with altitude than do the true and DBS directions. When a smaller spacing for the receiving array is used, it yields a smaller true velocity estimate.

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