The Chung‐Li VHF radar: Technical layout and a summary of initial results

The particular characteristics of the VHF mesosphere‐stratosphere‐troposphere (MST) radar and wind profiler system, operated at the National Central University in Chung‐Li, Taiwan, Republic of China, are described. These are the dual‐mode applications of the Doppler and the spaced antenna technique, where the latter is used in the conventional mode to determine the wind velocity as well as in the novel interferometer mode. A brief outline of the scientific rationale and the technical layout of this particular configuration of the Chung‐Li VHF radar is given. A generally applicable method for system performance checks by deducing principle radar data parameters before the data analysis has been developed and is briefly described. Receiver system and antenna calibration measurements with celestial radio sources are reported and prove the appropriateness of the antenna system. Radar reflectivity profiles, measured with vertical as well as with off‐vertical antenna beams, are presented and discussed. We also present height‐time‐reflectivity plots for quiet and disturbed weather conditions and reflect on their peculiarities. We show that the wind profiles measured with the conventional Doppler method and the spaced antenna method are in good agreement with radiosonde measurements. The spatial correlation parameters, deduced with the spaced antenna method, are consistent with results from other radars. We also discuss measurement capabilities to deduce the tropopause height with the Chung‐Li VHF radar. We also describe echo power variations due to focusing from reflectivity structures modulated by gravity waves and a brief case study of Kelvin‐Helmholtz instability. We finally outline future research directions which could be performed with the Chung‐Li VHF radar.