Turbulent upwelling of the mid‐latitude ionosphere: 1. Observational results by the MU radar

摘要: In this paper we present the detailed results of a series experiments designed to study coherent backscatter 50-MHz radar waves from mid-latitude F region. Data were obtained with active phased-array MU in Japan and include some auxiliary E region echoes as well. As other turbulent ionospheric phenomena intense nonthermal scatter comes irregularities oriented parallel B. The strongest correspond at least 20 dB stronger than thermal same frequency typical densities range. Simultaneous observations ionosondes show that these occur during strong spread F. defined by ionosondes, latter phenomenon is certainly much more widespread upwelling events described here, but believe sense most violent large patches which display away Doppler shifts corresponding irregularity motion upward northward radar. At edges there often brief period toward before echoing ceases. On rare occasions comparable are detected, although such cases width narrower echoes. characterized mean velocities well over 250 m/s widths (full half maximum) 50 m/s. multiple beam capability allowed us track zonal direction on two days. moved east west both 125 185 m/s, respectively. There distinct tendency for bottom contour scattering be modulated patch occurrence higher frequencies. This higher-frequency component may substructures detected simultaneously several experiments. companion (Kelley Fukao, issue), explore number possible explanations detail.