Evaluation of ionospheric models for Central and South Americas

Klipp, Telmo dos Santos; Petry, Adriano; Souza, J. R.; Falcão, Gabriel; Velho, Haroldo Fraga de Campos; Paula, E. R. de; Antreich, Felix; Hoque, Mainul; Kriegel, Martin; Berdermann, Jens; Jakowski, N.; Fernández-Gómez, I.; Borries, Claudia; Sato, Hiroatsu; Wilken, Volker

doi:10.1016/j.asr.2019.09.005

Cited by 9 publications

(4 citation statements)

References 19 publications

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“…Since the daily mean TEC values from flags 11 and 22 follow the IGS data variation, they are coherent. Such coherence has been well explained by Klipp et al (2019). These authors have analyzed the IGS TEC for the equatorial, low and mid latitudes and also for the same period as presented in this work.…”

Section: Methodssupporting

confidence: 74%

Ionosonde Total Electron Content Evaluation Using IGS Data

Klipp

Petry

Falcão

et al. 2019

Preprint

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Abstract. In this work, a period of two years (2016–2017) of vertical total electron content (VTEC) from ionosondes operating in Brazil is compared to the International GNSS Service (IGS) data. Sounding instruments from National Institute for Space Research (INPE) provided the ionograms used, which were filtered based on confidence score (CS) and C-level flags evaluation. Differences between TEC from IGS maps and ionograms were accumulated in terms of root mean square error (RMSE). It has been noticed the TEC values provided by ionograms are systematically underestimated, which is attributed to a limitation in the electron density modeled for the ionogram topside that considers maximum height only around 800–900 Km, while IGS takes in account electron density from GNSS stations up to the satellite network orbits. The ionogram topside profiles covering the plasmasphere were re-modeled using an adaptive alpha-Chapman exponential decay that includes a transition function between the F2 layer and plasmasphere, and electron density integration height was extended to compute TEC. Chapman parameters for the F2 layer were extracted from each ionogram, and plasmaspheric scale height was set to 10,000 Km. Our analysis has shown the plasmaspheric basis electron density, assumed to be proportional to the electron peak density, plays an important role to reduce the RMSE values. Depending on the proportionality coefficient choice, mean RMSE reached a minimum of 5.32 TECU, that is 23 % lower than initial ionograms TEC errors.

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Section: Methodssupporting

confidence: 74%

Ionosonde Total Electron Content Evaluation Using IGS Data

Klipp

Petry

Falcão

et al. 2019

Preprint

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“…The flux values provided by EUVAC are smaller than SO-LAR2000 results in the photoionization processes, and this results in a decrease in TEC. Klipp et al (2019) compared the IGS TEC with the modeled TEC using different flux models (EUVAC and SO-LAR2000) over Central and South American regions. They showed different behavior of empirical models during different solar activity conditions.…”

Section: Observed Tec Variations and Its Comparison To Tec Simulated Using Different Euv Flux Modelsmentioning

confidence: 99%

Ionospheric response to solar extreme ultraviolet radiation variations: comparison based on CTIPe model simulations and satellite measurements

Vaishnav¹,

Schmölter

Jacobi³

et al. 2021

Ann. Geophys.

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Abstract. The ionospheric total electron content (TEC) provided by the International GNSS Service (IGS) and the TEC simulated by the Coupled Thermosphere Ionosphere Plasmasphere Electrodynamics (CTIPe) model have been used to investigate the delayed ionospheric response against solar flux and its trend during the years 2011 to 2013. The analysis of the distinct low-latitude and midlatitude TEC response over 15∘ E shows a better correlation of observed TEC and the solar radio flux index F10.7 in the Southern Hemisphere compared to the Northern Hemisphere. Thus, a significant hemispheric asymmetry is observed. The ionospheric delay estimated using model-simulated TEC is in good agreement with the delay estimated for observed TEC against the flux measured by the Solar Dynamics Observatory (SDO) extreme ultraviolet (EUV) Variability Experiment (EVE). The average delay for the observed (modeled) TEC is 17(16) h. The average delay calculated for observed and modeled TEC is 1 and 2 h longer in the Southern Hemisphere compared to the Northern Hemisphere. Furthermore, the observed TEC is compared with the modeled TEC simulated using the SOLAR2000 and EUVAC flux models within CTIPe over northern and southern hemispheric grid points. The analysis suggests that TEC simulated using the SOLAR2000 flux model overestimates the observed TEC, which is not the case when using the EUVAC flux model.

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“…Total Electron Contents (TEC) values provided by IGS in the range covered by GNSS monitoring stations were assumed as reference, and were compared with the TEC estimates by the physics-based model (SUPIM) and an empirical model (Neustrelitz TEC Model-Global, NTCM-GL). The discrepancies between SUPIM, NTCM-GL and IGS were caused by the solar flux models used as parametric entries to the models (Klipp et al 2019). It is worth mentioning that the discrepancies in the NTCM-GL results only occur during rapid increases in solar fluxes.…”

Section: Ionospheric Dynamics Over Brazilmentioning

confidence: 98%

The GNSS NavAer INCT Project Overview and Main Results

Monico

Paula

Moraes

et al. 2022

J. Aerosp. Technol. Manag.

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Air navigation is increasingly dependent on the use of Global Navigation Satellite Systems (GNSS). It allows the determination of the aircraft's position in all phases of the flight and brings many advantages. Although GNSS navigation results in gains, the radio signals from these systems are strongly influenced by the ionospheric environment. It introduces errors that can affect the accuracy, integrity, availability and continuity requirements established by the International Civil Aviation Organization (ICAO). The ionospheric layer has different behaviors depending on the latitude, time of day, season of the year, geomagnetic activity and solar cycle. Since Brazil is located in a region of low latitudes, it experiences a series of unique challenges when compared to regions of mid-latitudes. For this reason, the application of GNSS-based technologies in aviation over the Brazilian territory requires an in-depth assessment of the ionosphere effects. Therefore, the Instituto Nacional de Ciência e Tecnologia (INCT) named GNSS Technology for Supporting Air Navigation was formed in 2017 to better assess the ionosphere impacts and assist government agencies and companies in the development of safe air navigation procedures over Brazil in a near future. This paper presents the most relevant advances achieved so far within this multidisciplinary project that involves Brazilian research centers and universities.

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Evaluation of ionospheric models for Central and South Americas

Cited by 9 publications

References 19 publications

Ionosonde Total Electron Content Evaluation Using IGS Data

Ionosonde Total Electron Content Evaluation Using IGS Data

Ionospheric response to solar extreme ultraviolet radiation variations: comparison based on CTIPe model simulations and satellite measurements

The GNSS NavAer INCT Project Overview and Main Results

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