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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

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

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Correia, Emilia [1, 2] ; Medeiros Raunheitte, Luis Tiago [2] ; Bageston, Jose Valentin [3] ; D'Amico, Dino Enrico [2]
Total Authors: 4
[1] INPE, Sao Jose Dos Campos, SP - Brazil
[2] Univ Presbiteriana Mackenzie, Ctr Radio Astron & Astrofis Mackenzie, Sao Paulo, SP - Brazil
[3] CRS INPE, Ctr Reg Sul Pesquisas Espaciais, Santa Maria, RS - Brazil
Total Affiliations: 3
Document type: Journal article
Source: Annales Geophysicae; v. 38, n. 2, p. 385-394, MAR 24 2020.
Web of Science Citations: 0

The goal of this work is to investigate the gravity wave (GW) characteristics in the low ionosphere using very low frequency (VLF) radio signals. The spatial modulations produced by the GWs affect the conditions of the electron density at reflection height of the VLF signals, which produce fluctuations of the electrical conductivity in the D region that can be detected as variations in the amplitude and phase of VLF narrowband signals. The analysis considered the VLF signal transmitted from the US Cutler, Maine (NAA) station that was received at Comandante Ferraz Brazilian Antarctic Station (EACF, 62.1 degrees S, 58.4 degrees W), with its great circle path crossing the Drake Passage longitudinally. The wave periods of the GWs detected in the low ionosphere are obtained using the wavelet analysis applied to the VLF amplitude. Here the VLF technique was used as a new aspect for monitoring GW activity. It was validated comparing the wave period and duration properties of one GW event observed simultaneously with a co-located airglow all-sky imager both operating at EACF. The statistical analysis of the seasonal variation of the wave periods detected using VLF technique for 2007 showed that the GW events occurred all observed days, with the waves with a period between 5 and 10 min dominating during night hours from May to September, while during daytime hours the waves with a period between 0 and 5 min are predominant the whole year and dominate all days from November to April. These results show that VLF technique is a powerful tool to obtain the wave period and duration of GW events in the low ionosphere, with the advantage of being independent of sky conditions, and it can be used during the whole day and year-round. (AU)

FAPESP's process: 19/05455-2 - Characterization of the ionospheric dynamics in the South American sector and Antarctica under the space weather conditions
Grantee:Emilia Correia
Support type: Regular Research Grants