The influence of tidal winds in the formation of blanketing sporadic e-layer over equatorial Brazilian region

Resende, L. C. A.; Batista, I. S.; Denardini, Clezio Marcos; Batista, P. P.; Carrasco, A. J.; Andrioli, V. F.; Moro, Juliano

doi:10.1016/j.jastp.2017.06.009

Cited by 29 publications

(56 citation statements)

References 28 publications

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“…We used the MIRE originally developed by Carrasco (2005) and Carrasco et al (2007), which was modified by Resende et al (2017aResende et al ( , 2017b. The extended version of MIRE included two major modifications: (1) Inclusion of a new wind model that correctly describes the wind dynamic over the Brazilian region; and (2) the seasonal variability of the metallic ions in the Es layer formation.…”

Section: Mire Modelmentioning

confidence: 99%

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Occurrence and Modeling Examination of Sporadic‐E Layers in the Region of the South America (Atlantic) Magnetic Anomaly

et al. 2019

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In this work, the occurrence of different types of sporadic-E layers (Es) was described for two stations located in the region of the South America Magnetic Anomaly: Jataí and São José dos Campos. The results show the hourly and monthly values of the Es occurrences and presented five types of layers (cusp, high, flat, low, and slant), with the flat/low types (Es f/l ) being the most frequent over both stations. We also analyzed the Es layer parameters of blanketing frequency (f b Es) and top frequency (f t Es) obtained from ionosonde data during storm-time periods, in order to investigate possible evidences of energetic particle-induced E-layer ionization. The results revealed increases in the values of the nighttime f t Es and f b Es, which can be related to the particle precipitation in the South America Magnetic Anomaly region. Additionally, we investigated the roles of the wind shear mechanism in the formation of the Es types by using a modified form of the Ionospheric E-Region Model (MIRE), which incorporates tidal winds obtained from meteor radar data. Furthermore, the electron densities deduced from f b Es parameter were compared with the maximum electron densities obtained from MIRE simulations. Depending on local time and season, the initial results revealed for both stations some discrepancies between modeled and measured electron densities. However, a better fitting was obtained when the amplitudes of the zonal/meridional wind components were adjusted by some factor, which may be attributed to the possible effects of day-to-day tidal wind variability and their interaction with gravity and planetary waves.Key Points:• The flat/low Es are the most frequent types of sporadic layers observed at the low-latitude stations • Es frequency parameters during moderate storms showed evidences of energetic particle-induced E-layer ionization around the SAMA region • Modeled and measured electron densities revealed the role of the wind shear mechanism in the formation of the observed Es layers

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Section: Mire Modelmentioning

confidence: 99%

“…However, we performed some modifications in MIRE to obtain a more realistic wind profile. In fact, Resende et al (2017aResende et al ( , 2017b) considered a constant wavelength in their simulations. Here, we adjust a wavelength tending to infinity above 120 km.…”

Section: Meteor Radar Wind Datamentioning

confidence: 99%

Occurrence and Modeling Examination of Sporadic‐E Layers in the Region of the South America (Atlantic) Magnetic Anomaly

et al. 2019

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“…CO 2 mixing ratios are taken as constant with height until 87.5 km, and then decrease exponentially. Chemical heating due to recombination of O 2 and O (Riese et al, 1994), and heating due to extreme ultraviolet radiation, are added. This is described in more detail by Fröhlich et al (2003a).…”

Section: Muam Circulation Model Predictionsmentioning

confidence: 99%

Quarterdiurnal signature in sporadic E occurrence rates and comparison with neutral wind shear

et al. 2019

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Abstract. The GPS radio occultation (RO) technique is used to study sporadic E (Es) layer plasma irregularities of the Earth's ionosphere on a global scale using GPS signal-to-noise ratio (SNR) profiles from the COSMIC/FORMOSAT-3 satellite. The maximum deviation from the mean SNR can be attributed to the height of the Es layer. Es are generally accepted to be produced by ion convergence due to vertical wind shear in the presence of a horizontal component of the Earth's magnetic field, while the wind shear is provided mainly by the solar tides. Here we present analyses of quarterdiurnal tide (QDT) signatures in Es occurrence rates. From a local comparison with mesosphere/lower thermosphere wind shear obtained with a meteor radar at Collm (51.3∘ N, 13.0∘ E), we find that the phases of the QDT in Es agree well with those of negative vertical shear of the zonal wind for all seasons except for summer, when the QDT amplitudes are small. We also compare the global QDT Es signal with numerical model results. The global distribution of the Es occurrence rates qualitatively agrees with the modeled zonal wind shears. The results indicate that zonal wind shear is indeed an important driving mechanism for the QDT seen in Es.

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“…Sporadic layers (Es) are electron density enhancements which appear in the lower ionospheric E region at heights between 90 and 130 km with a typical thickness of less than 5 km. The layers consist mainly of metallic ions (Fe + , Mg + , Ca + and Na + ) deposited by meteoric ablation (Whitehead, 1961;Layzer, 1972). The metallic ions have longer lifetimes than the nonmetallic ionized air constituents (O + , NO + , O 2 + ), which allow the formation of long-lasting sporadic E layers (Kopp, 1997).…”

Section: Introductionmentioning

confidence: 99%

Study of sporadic E layers based on GPS radio occultation measurements and digisonde data over the Brazilian region

et al. 2018

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This work presents new results about sporadic E-layers (Es layers) using GPS (global positioning system) radio occultation (RO) measurements obtained from the FORMOSAT-3/COSMIC satellites and digisonde data. The RO profiles are used to study the Es layer occurrence as well as its intensity of the signal-to-noise ratio (SNR) of the 50 Hz GPS L1 signal. The methodology was applied to identify the Es layer on RO measurements over Cachoeira Paulista, a low-latitude station in the Brazilian region, in which the Es layer development is not driven tidal winds only as it is at middle latitudes. The coincident events were analyzed using the RO technique and ionosonde observations during the year 2014 to 2016. We used the electron density obtained using the blanketing frequency parameter (fbEs) and the Es layer height (h'Es) acquired from the ionograms to validate the satellite measurements. The comparative results show that the Es layer characteristics extracted from the RO measurements are in good agreement with the Es layer parameters from the digisonde.

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The influence of tidal winds in the formation of blanketing sporadic e-layer over equatorial Brazilian region

Cited by 29 publications

References 28 publications

Occurrence and Modeling Examination of Sporadic‐E Layers in the Region of the South America (Atlantic) Magnetic Anomaly

Occurrence and Modeling Examination of Sporadic‐E Layers in the Region of the South America (Atlantic) Magnetic Anomaly

Quarterdiurnal signature in sporadic E occurrence rates and comparison with neutral wind shear

Study of sporadic E layers based on GPS radio occultation measurements and digisonde data over the Brazilian region

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