English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

. The goal of this work is to investigate the gravity wave (GW)characteristics in the low ionosphere using very low frequency (VLF) radiosignals. The spatial modulations produced by the GWs affect the conditionsof the electron density at reflection height of the VLF signals, whichproduce fluctuations of the electrical conductivity in the D region that canbe detected as variations in the amplitude and phase of VLF narrowbandsignals. The analysis considered the VLF signal transmitted from the USCutler, Maine (NAA) station that was received at Comandante Ferraz BrazilianAntarctic Station (EACF, 62.1 ∘  S, 58.4 ∘  W), with its great circlepath crossing the Drake Passage longitudinally. The wave periods of the GWsdetected in the low ionosphere are obtained using the wavelet analysisapplied to the VLF amplitude. Here the VLF technique was used as a newaspect for monitoring GW activity. It was validated comparing the waveperiod and duration properties of one GW event observed simultaneously witha co-located airglow all-sky imager both operating at EACF. The statisticalanalysis of the seasonal variation of the wave periods detected using VLFtechnique for 2007 showed that the GW events occurred all observed days,with the waves with a period between 5 and 10 min dominating during nighthours from May to September, while during daytime hours the waves witha period between 0 and 5 min are predominant the whole year and dominateall days from November to April. These results show that VLF technique is apowerful tool to obtain the wave period and duration of GW events in the lowionosphere, with the advantage of being independent of sky conditions, and it canbe used during the whole day and year-round.

Characterization of gravity waves in the lower ionosphere using very low frequency observations at Comandante Ferraz Brazilian Antarctic Station