In this paper we confine our attention to the analysis of amplitude and phase data acquired by monitoring VLF/LF radio signals emitted by four European transmitters during a seven-year period (2008-2014). All the data were recorded at a Belgrade site (44.85^{0} N, 20.38^{0} E) by the Stanford University ELF/VLF receiver AWESOME. Propagation of VLF/LF radio signal takes place in the Earth-ionosphere waveguide and strongly depends on ionization level of the D-region, which means that it is mainly controlled by solar conditions. Some results of amplitude and phase variations on GQD/22.10 kHz, DHO/23.40 kHz, ICV/20.27 kHz and NSC/45.90 kHz radio signals measurements at short distances (D < 2 Mm) over Central Europe and their interpretation are summarized in this paper. Attention is restricted to regular diurnal, seasonal and solar variations including sunrise and sunset effects on propagation characteristics of four VLF/LF radio signals. We study VLF/LF propagation over short path as a superposition of different number of discrete modes which depends on the variations of the path parameters. Although the solar X-ray flare effects on propagation of VLF/LF radio signals are well recognized on all paths, similarities and differences between them are defined under existing conditions over the paths. Statistical results show that the size of amplitude and phase perturbations on VLF/LF radio signal is in correlation with the intensity of X-ray flux. We present the calculations of electron density enhancements in the D-region caused by different classes of solar X-ray flares during the period of ascending phase and maximum of the solar cycle 24.


    Access

    Access via TIB

    Check availability in my library

    Order at Subito €


    Export, share and cite



    Title :

    A study of VLF signals variations associated with the changes of ionization level in the D-region in consequence of solar conditions



    Published in:

    Publication date :

    2016




    Type of media :

    Article (Journal)


    Type of material :

    Print


    Language :

    English



    Classification :

    BKL:    55.60 Raumfahrttechnik / 50.93 / 55.60 / 50.93 Weltraumforschung





    On climbing fiber signals and their consequence(s)

    Simpson, J. I. / Wylie, D. R. / De Zeeuw, C. I. et al. | British Library Conference Proceedings | 1997


    More on climbing fiber signals and their consequence(s)

    Simpson, J. I. / Wylie, D. R. / De Zeeuw, C. I. et al. | British Library Conference Proceedings | 1997