Detection of Daytime Ionospheric Irregularities at Low Latitudes With a Multistatic HF Radar

We report a new observation of daytime ionospheric irregularities on December 27, 2009, at low latitudes in China using multistatic HF radar. The transmitter, with a horizontal polarization log-periodic antenna pointing westward, is located at Wanning (18.97° N, 110.50° E, dip angle 19°). Three separate receivers are in Sanya (18.20° N, 109.49° E), Qiongzhong (19.04° N, 109.77° E), and Tunchang (19.42° N, 110.13° E). Doppler spectra, frequency power spectra, and wavenumber power spectra from the three receivers were calculated. The main features of these observations are: 1) the irregularities observed at 12:10 (LT) had typical lengths on the scale of tens of meters and the altitude was in the range of 105–175 km, which is located in the E region and bottom of the F region; 2) the power distributions from the three receivers are consistent with the irregularities being field aligned; and 3) features consistent with a cascade of irregular spatial scales were observed. We suggest that the observed irregularity could be due to the intermediate layer modulated by electrodynamic instability.