The ionospheric sounding data at two southern hemisphere stations, the Argentine Islands and Port Stanley, are analyzed using a method previously developed by the authors. Negative trends of the critical frequency foF2 are found for both stations. The magnitudes of the trends are close to those at the corresponding (close geomagnetic latitude) stations of the northern hemisphere, as considered ...

Abstract. In this work, Neural-Network-based single-station hourly daily foF2 and M(3000)F2 modelling of 15 European ionospheric stations is investigated. The data used are neural networks and hourly daily values from the period 1964– 1988 for training the neural networks and from the period 1989–1994 for checking the prediction accuracy. Two types of models are presented for the F2-layer criti...

This paper develops a significance test for evaluating the equality of the mean functions in two samples of spatially indexed functional data. The problem is motivated by an important question in space physics research which is related to the hypothesis of ionospheric global cooling (as opposed to the conjectured global warming of near surface atmosphere). The critical electron frequency of the...

To further improve the prediction accuracy of critical frequency ionospheric F2 layer (foF2), we use machine learning method (ML) to establish an explanatory dynamic model predict foF2. Firstly, according ML modeling process, three elements establishing a foF2 and four problems be solved are determined, idea concrete steps building determined. Then data collection is explained in detail, change...

The ionospheric effects of six intense geomagnetic storms with Dst index ≤ −100 nT that occurred in 2012 were studied at a low-latitude station, Darwin (Geomagnetic coordinates, 21.96° S, 202.84° E), low-mid-latitude Townsville (28.95° 220.72° and mid-latitude Canberra (45.65° 226.30° the Australian Region, by analyzing storm–time variations critical frequency F2-region (foF2). Out storms, stor...

Data of foF2, hmF2, B0 and B1 with half hourly interval resolution, which are scaled and deduced from ionograms recorded by DPS-4 digisonde at the low latitude station Hainan, China for the time period of March–August 2002, are analyzed for the diurnal and seasonal variation behavior of the ionosphere using the calculated monthly medians. Comparisons between the observational result and that of...

Background/Objectives: The ionospheric response to the tropical cyclone (TC) OCKHI of December 2017 in equatorial region is presented study. Methods/Statistical analysis: includes a change Total Electron Content (TEC) utilized using stations Tirunelveli and Bangalore. critical frequency (foF2) from Ionosonde over station also considered study TC effect F2 ionosphere. Findings: It has been obser...

With a new factor, effective sunspot number R eff , the results show that there were giant positive disturbances of foF2 around the epicentral zone on 9 May, 3 days prior to the earthquake. Our results indicate that the observed positive ionospheric disturbances were most possibly associated with the imminent earthquake and the new analytic method has good prospects in practice.

[1] Knowledge of solar sector polarity effects on the ionosphere may provide some clues in understanding of the ionospheric day-to-day variability and “hysteresis” effect on foF2. Ionospheric response to changes in solar sector polarity has not been fully documented previously, partly due to the limitation of observations. In this study, a solar-terrestrial connection ranging from solar sector ...

This study is the first which gives the climatology of the ionosphere at the northern tropical crest of ionization in the Asian sector. We use the data from Phu Thuy station, in Vietnam, through three solar cycles (20, 21 and 22), showing the complete morphology of ionosphere parameters by analyzing long term variation, solar cycle variation and geomagnetic activity effects, seasonal evolution ...