Bibliography

Ionospheric Response Over Brazil to the August 2018 Geomagnetic Storm as Probed by CSES-01 and Swarm Satellites and by Local Ground-Based Observations

The geomagnetic storm that occurred on 25 August 25 2018, that is, during the minimum of solar cycle 24, is currently the strongest ever probed by the first China Seismo-Electromagnetic Satellite (CSES-01). By integrating the in situ measurements provided by CSES-01 (orbiting at altitude of 507 km) and by Swarm A satellite (orbiting at ca., 460 km) with ground-based observations (ionosondes, magnetometers, and Global Navigation Satellite System receivers), we investigate the ionospheric response at lower- and mid-latitudes over Brazil. Specifically, we investigate the electrodynamic disturbances driven by solar wind changes, by focusing on the disturbances driving modifications of the equatorial electrojet (EEJ). Our proposed multisensor technique analysis mainly highlights the variations in the topside and bottomside ionosphere, and the interplay between prompt penetrating electric fields and disturbance dynamo electric fields resulting in EEJ variations. Thanks to this approach and leveraging on the newly available CSES-01 data, we complement and extend what recently investigated in the Western South American sector, by highlighting the significant longitudinal differences, which mainly come from the occurrence of a daytime counter-EEJ during both 25 and 26 August at Braziliian longitudes and during part of 26 August only in the Peruvian sector. In addition, the increased thermospheric circulation driven by the storm has an impact on the EEJ during the recovery phase of the storm. The observations at the CSES-01/Swarm altitudes integrated with the ground-based observation recorded signatures of equatorial ionospheric anomaly crests formation and modification during daytime coupled with the positive ionospheric storm effects at midlatitude.

Spogli, L.; Sabbagh, D.; Regi, M.; Cesaroni, C.; Perrone, L.; Alfonsi, L.; Di Mauro, D.; Lepidi, S.; Campuzano, S.; Marchetti, D.; De Santis, A.; Malagnini, A.; Scotto, C.; Cianchini, G.; Shen, Xu; Piscini, A.; Ippolito, A.;

Published by: Journal of Geophysical Research: Space Physics      Published on:

YEAR: 2021     DOI: 10.1029/2020JA028368

Geomagnetic storms; Equatorial Electrojet; in situ plasma density; ionospheric elctroduamics; Ionospheric storms; low-latitude ionosphere

Longitudinal variations in thermospheric parameters under summer noontime conditions inferred from ionospheric observations: A comparison with empirical models

Mikhailov, Andrey; Perrone, Loredana;

Published by: Scientific reports      Published on:

YEAR: 2019     DOI:

The annual asymmetry in the F ₂ layer during deep solar minimum (2008-2009): December anomaly

Annual January/July midlatitude daytime asymmetry in monthly median N_mF₂ and model thermospheric parameters has been considered during deep solar minimum, (2008\textendash2009), when solar and geomagnetic activities were at the lowest level, to analyze the background effect due to the Sun-Earth minimum distance, perihelion, in the vicinity of the December solstice. Averaged over 10 midlatitude station pairs, the N_mF₂ asymmetry was found to be ≈1.23, while the average asymmetry for the annual component in N_mF₂ variations is ≈1.17. Annual asymmetry in monthly median neutral composition and temperature predicted by Mass Spectrometer Incoherent Scatter 86 (MSIS86) and MSISE00 thermospheric models along with the 7\% increase in solar EUV flux in the vicinity of the December solstice is sufficient to explain the observed annual asymmetry in N_mF₂. A hierarchy of aeronomic parameters responsible for the observed asymmetry in N_mF₂ has been established: the main contributor is atomic oxygen\textemdashabout 50\% of the total effect, [N₂] contributes around 35\% strongly compensating the [O] contribution, and solar EUV and T_n provide \<10\% each. The zonal mean annual asymmetry in MSIS86 atomic oxygen column density was shown to be 1.18 at low and middle latitudes, and this is close to the estimated asymmetry for the annual component in N_mF₂ variations. The earlier proposed mechanism of the December anomaly is considered as a plausible one to explain the 1.18 January/July asymmetry in the atomic oxygen variations and consequently the N_mF₂ annual daytime asymmetry at middle latitudes under the deep solar minimum.

Mikhailov, A.; Perrone, L.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 02/2015

YEAR: 2015     DOI: 10.1002/2014JA020929

midlatitude ionosphere; thermosphere composition and structure

Two types of positive disturbances in the daytime mid-latitude F2-layer: morphology and formation mechanisms

Mikhailov, A.V.; Perrone, L.; Smirnova, N.V.;

Published by: Journal of Atmospheric and Solar-Terrestrial Physics      Published on: Jan-06-2012

YEAR: 2012     DOI: 10.1016/j.jastp.2012.04.003

Retrieval of thermospheric parameters from routine ionospheric observations: assessment of method\textquoterights performance at mid-latitudes daytime hours

A new method has been developed to retrieve neutral temperature T_n and composition [O], [N₂], [O₂] from electron density profiles in the daytime mid-latitude F₂-region under both quiet and disturbed conditions. A comparison with CHAMP neutral gas density observations in the vicinity of Millstone Hill Incoherent Scatter Radar (ISR) has shown that the retrieved neutral gas densities coincide with the observed ones within the announced accuracy of CHAMP observations, provided that accurate N_e(h) ISR profiles are used for the retrieval. The performance of the method has also been tested ingesting Digisonde N_e(h) profiles. In this case the agreement with CHAMP neutral gas density observations is less successful. Possible factors that can influence the performance accuracy are investigated. These are mostly related to limitations due to the ionogram scaling and inversion methods, including performance limitations of the sounding technique itself, like for instance during G-conditions. Several tests presented here demonstrate that discrepancies in the hmF2 values provided by the Digisondes could have an important impact on the performance of the method. It should be noted that in all tests performed here using Digisonde N_e(h) profiles, the topside part is approximated with the NeQuick model and any assessment concerning the impact of the topside profiler on the accuracy of the method is beyond the scope of this investigation. Despite the limitations related to the use of Digisonde profiles, the proposed method has the potential to monitor the thermosphere at least with ISR N_e(h) profiles. Digisonde electron density profiles can also be used if quality improvements are made concerning the ionogram inversion methods.

Mikhailov, A.V.; Belehaki, A.; Perrone, L.; Zolesi, B.; Tsagouri, I.;

Published by: Journal of Space Weather and Space Climate      Published on: 06/2012

YEAR: 2012     DOI: 10.1051/swsc/2012002

ionosphere/atmosphere interactions; ionosphere: instruments; Ionospheric storms; techniques; thermospheric dynamics; topside ionosphere

Retrieval of thermospheric parameters from routine ionospheric observations: assessment of method’s performance at mid-latitudes daytime hours

Satellite observations similar to CHAMP or TIMED/GUVI provide valuable information on the thermosphere but they can be used only for scientific research rather than applications as a

Mikhailov, AV; Belehaki, A; Perrone, L; Zolesi, B; Tsagouri, I;

Published by: Journal of Space Weather and Space Climate      Published on:

YEAR: 2012     DOI: https://doi.org/10.1051/swsc/2012002

On the mechanism of seasonal and solar cycle NmF2 variations: A quantitative estimate of the main parameters contribution using incoherent scatter radar observations

Mikhailov, A.; Perrone, L.;

Published by: Journal of Geophysical Research      Published on: Jan-01-2011

YEAR: 2011     DOI: 10.1029/2010JA016122