OIASA application to oblique radio-sounding data recorded in Korea

Abstract

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.