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Assessment of electron density profiles over the Brazilian Region using radio occultation data aided by global ionospheric maps

Jerez, Gabriel and Prol, Fabricio and Alves, Daniele and Monico, João and Hernández-Pajares, Manuel (2020) Assessment of electron density profiles over the Brazilian Region using radio occultation data aided by global ionospheric maps. EGU General Assembly 2020, 4–8 May 2020, Online. doi: 10.5194/egusphere-egu2020-325.

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Official URL: https://meetingorganizer.copernicus.org/EGU2020/EGU2020-325.html

Abstract

The development of GNSS (Global Navigation Satellite System) and LEO (Low Earth Orbiting) satellites missions enhanced new possibilities of the terrestrial atmosphere probing. The Radio Occultation (RO) technique can be used to retrieve profiles from the neutral and the ionized atmosphere. An important advantage of using RO data is the spatial distribution, which enables global coverage. The signal transmitted by GNSS satellites and tracked by receivers embedded at the LEO satellites is influenced by the atmosphere which causes signal refraction. Due to the signal and atmospheric interaction, instead of a straight line, the signal propagates as a curved line in the path between the transmitter and receiver. The satellites geometry allows the retrieval of atmospheric refractive index, which carries several characteristics from ist composition, such as pressure and temperature of the neutral atmosphere, and electron density of the ionosphere. In 1995 GPS/MET (Global Positioning System/Meteorology) experiment was launched to prove the RO concept and, since then, several LEO missions with GNSS receiver embedded were developed, such as CHAMP (Challenging Mini-satellite Payload) (2001-2008), SAC-C (Satélite de Aplicaciones Cientificas-C) (2001-2013) and COSMIC (Constellation Observing System for Meteorology, Ionosphere and Climate) (2006-present). COSMIC is one of the RO missions with the greatest amount of atmospheric data available, mainly taking into account ionospheric information. In the RO technique, in general, the Abel retrieval is used to retrieve the refractive index. The Abel retrieval assumes a spherical symmetry of the atmosphere. When considering the electron density profiles, the main issue is related to regions with large horizontal gradients, where the spherical assumption presents the biggest degradation. In order to improve the ionospheric horizontal gradient used to retrieve electron density profiles, many researches have performed experiments using data from different sources. In this paper, we aimed to assess the electron density profiles over the Brazilian area (equatorial region), characterized by intense ionospheric variability, considering RO data and Global Ionospheric Maps (GIM). The data used is from COSMIC mission, in a period close to the last solar cycle peak (2013-2014). Ionosonde data were used as reference values to assess the RO with GIM aided data. Total Electron Content (TEC) data from GIM were used to estimate the variability of ionosphere between the ionosonde position and the profile locations. This research builds on a preliminary investigation related to the assessment of ROionospheric profiles over a region under intense ionospheric variability, such as the Brazilian territory. Future works may take into consideration the use of other ionospheric information such as regional ionospheric maps, with higher resolution, and ionospheric tomography.

Item URL in elib:https://elib.dlr.de/135203/
Document Type:Conference or Workshop Item (Other)
Title:Assessment of electron density profiles over the Brazilian Region using radio occultation data aided by global ionospheric maps
Authors:
AuthorsInstitution or Email of AuthorsAuthor's ORCID iD
Jerez, GabrielSao Paulo State University (UNESP)https://orcid.org/0000-0001-6893-2144
Prol, FabricioGerman Aerospace Center (DLR)https://orcid.org/0000-0002-7206-1705
Alves, DanieleSao Paulo State University (UNESP)UNSPECIFIED
Monico, JoãoSao Paulo State University (UNESP)UNSPECIFIED
Hernández-Pajares, ManuelUniversitat Politècnica de Catalunya (UPC-IonSA)UNSPECIFIED
Date:2020
Refereed publication:No
Open Access:Yes
Gold Open Access:No
In SCOPUS:No
In ISI Web of Science:No
DOI:10.5194/egusphere-egu2020-325
Status:Published
Keywords:radio-occultation; COSMIC; GPS/MET; SAC-C; GNSS; TEC; ionosphere
Event Title:EGU General Assembly 2020
Event Location:Online
Event Type:international Conference
Event Dates:4–8 May 2020
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Space
HGF - Program Themes:Communication and Navigation
DLR - Research area:Raumfahrt
DLR - Program:R KN - Kommunikation und Navigation
DLR - Research theme (Project):R - Vorhaben Ionosphäre (old)
Location: Neustrelitz
Institutes and Institutions:Institute for Solar-Terrestrial Physics > Space Weather Observation
Deposited By: Dos Santos Prol, Fabricio
Deposited On:01 Oct 2020 11:19
Last Modified:01 Oct 2020 11:19

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