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Studying tsunami effects on ionospheric parameters using global positioning system
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Zahra Foroodi   , Mahammad Mahdi Alizadeh Elizei * |
| K.N Toosi University of Technology |
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Abstract: (1865 Views) |
| The rapid displacement of the ocean floor during large ocean earthquakes causes the propagation of tsunami waves on the surface of sea and gravity waves in the atmosphere. Gravity are buoyancy oscillations that can propagate both horizontally and vertically and their propagation is under gravity force of earth effect. Gravity waves pierce the ionosphere layer after passing through the troposphere layer. In addition to transferring energy to the ionosphere, cause significant changes in ionospheric parameters, so they have significant effects on the propagation of radio waves through this dispersive medium. In this study, two-frequency measurements of the Global Positioning System (GPS) and ionosonde were used to determine the duration and effect of ionospheric perturbations in response to the tsunami induced by the 2011 Tokyo earthquake. The critical frequency of the F2 layer (fof2) data also showed clear disturbances that were consistent with GPS observation. Furthermore, gravity waves and tsunami waves have similar propagation properties, so gravity waves can be used for tsunami warnings. To further investigate the spatial variation in ionospheric electron density (IED) was used from FORMOSAT-3/COSMIC satellites electron density of ionospheric profiles for both reference and observation periods. the reduction in IED started from 200km and continued up to 272km altitude, and the minimum reduction was 2.2×105 el/cm3 that has happened in the 225 km altitude. The IED increased up to 767 km altitude continuously such that the maximum increase was 3.92×105 el/cm3 in 357 km altitude. |
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| Keywords: ionospheric disturbances, gravity waves, coupling ionosphere and troposphere, tsunami |
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Full-Text [PDF 1712 kb]
(320 Downloads)
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Type of Study: Research |
Subject:
Geodesy
Received: 2020/12/13 | Accepted: 2021/02/13 | ePublished ahead of print: 2022/01/1 | Published: 2022/11/1
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