Bullett, Terence

The Oblique Ionogram Automatic Scaling Algorithm (OIASA) has been applied to a data set of oblique ionograms recorded by the Vertical Incidence Pulsed Ionospheric Radar, Version 2 (VIPIR2) ionosonde receiver in Korea. These ionograms are the result of the real-time oblique radio-soundings performed every 15 minutes since September 12, 2016 (day 256) between the Japanese National Institute of Communications Technology ionospheric stations of Kokubunji (35.71°N, 139.46°E), Yamagawa (31.18°N, 130.59°E), Ogimi (26.70°N, 128.12°E), and Sarabetsu (45.18°N, 141.76°E), and the Korean Space Weather Center stations of Icheon (37.14°N, 127.55°E) and Jeju (33.43°N, 126.29°E). A set of 288 poor-quality test mode ionograms for each of the 8 different radiolinks has been selected for this study, and the results are presented. In order to scale the Maximum Usable Frequencies (MUF) between the receiving and the transmitting ionosondes, a filtering procedure for the ionograms noise reduction has been applied in combination with an image recognition technique. Vertical equivalent ionograms have been then obtained using Martyn’s equivalent path theorem, and processed by Autoscala.

In November 2008, the ionosonde station at Boulder, Colorado, USA (40.0°N; 105.3°W) became the host of a new ionosonde (VIPIR, Vertical Incidence Pulsed Ionospheric Radar) developed and built by Scion Associates. The VIPIR is a fully digital frequency agile radar that operates between 0.3 and 26 MHz. It features 8 digital receivers and a digital transmit exciter. Extremely high performance analog receive electronics and a 4 kW solid state amplifier provide interface to the real world. This work describes the application of Autoscala to the ionograms recorded by this ionosonde. First results, in terms of ionograms and autoscaled characteristics, are presented and discussed.