New Chung-Li Ionosonde in Taiwan: System Description and Preliminary Results

In spite of being interrupted several times in its long history operation since 1950, the routine observation ionosphere with various ionosondes installed at Chung-Li station Taiwan has been achieved successively for more than seven decades. this article, system characteristics latest ionosonde and algorithm developed by National Central University ionogram scaling true height analysis, which started to routinely operate 2020, are introduced. The new is a pulse radar that transmits train short pulses respective carrier frequencies between 2 30 MHz frequency separation 50 kHz. duration an entire sweep 294.13 s, divided into 561 channels. 16-bit complementary code employed increase signal-to-noise reflected echoes. observational range from 70 1221 km resolution 3.84 km. We automatically scale such profile ionospheric electron density can be retrieved. observed traces ordinary wave (O-wave) extraordinary (X-wave) displayed on were first identified separated using 2-dimensional autocorrelation analysis combined image projection method. used stepwise regression. With help International Reference Ionosphere (IRI) model Quasi-Parabolic Segment (QPS) model, we carried out retrieve based O-wave trace. An examination showed parameters (i.e., foF2, h’F2) retrieved automatic essentially good agreement those obtained manual scaling. ionosonde-measured foF2 hmF2 also compared FORMOSAT-7 measurements made GPS radio occultation technique. results show correlation coefficient, root mean squared deviation, difference were, respectively, ranges 0.878 0.93, 0.73 1.06 MHz, −0.43 −0.26 0.701 0.8, 22.39 28.45 km, −9.28 11.06 hmF2.