Thickness parameters in the empirical modeling of bottomside electron density profiles

Radicella, S. M.; Alazo-Cuartas, K.; Migoya-Orué, Yenca; Kashcheyev, A.

doi:10.1016/j.asr.2020.12.037

Cited by 5 publications

(6 citation statements)

References 8 publications

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“…The assimilation of storm time experimentally derived thickness parameter B2 into empirical models to improve the ability of such models to be adapted to different geomagnetic conditions is planned to be investigated. Such investigation is in line with the results obtained by [14,15].…”

Section: Supplementary Materialssupporting

confidence: 92%

“…More recently, ref. [15] discussed the performance of different options for thickness parameters in IRI and NeQuick models by comparing modeled and experimental profiles. At the same time, they proposed the use of experimentally derived thickness parameters in the models to better represent and also forecast the electron density profile.…”

Section: Introductionmentioning

confidence: 99%

“…At the same time, they proposed the use of experimentally derived thickness parameters in the models to better represent and also forecast the electron density profile. The climate behavior of experimentally derived and modelled thickness parameters have been studied regionally and globally [15][16][17][18], while their behavior under storm conditions has not been fully explored.…”

Section: Introductionmentioning

confidence: 99%

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B2 Thickness Parameter Response to Equinoctial Geomagnetic Storms

Migoya-Orué

Alazo-Cuartas

Kashcheyev

et al. 2021

Sensors

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The thickness parameters that most empirical models use are generally defined by empirical relations related to ionogram characteristics. This is the case with the NeQuick model that uses an inflection point below the F2 layer peak to define a thickness parameter of the F2 bottomside of the electron density profile, which is named B2. This study is focused on the effects of geomagnetic storms on the thickness parameter B2. We selected three equinoctial storms, namely 17 March 2013, 2 October 2013 and 17 March 2015. To investigate the behavior of the B2 parameter before, during and after those events, we have analyzed variations of GNSS derived vertical TEC (VTEC) and maximum electron density (NmF2) obtained from manually scaled ionograms over 20 stations at middle and low latitudes of Asian, Euro-African and American longitude sectors. The results show two main kinds of responses after the onset of the geomagnetic events: a peak of B2 parameter prior to the increase in VTEC and NmF2 (in ~60% of the cases) and a fluctuation in B2 associated with a decrease in VTEC and NmF2 (~25% of the cases). The behavior observed has been related to the dominant factor acting after the CME shocks associated with positive and negative storm effects. Investigation into the time delay of the different measurements according to location showed that B2 reacts before NmF2 and VTEC after the onset of the storms in all the cases. The sensitivity shown by B2 during the studied storms might indicate that experimentally derived thickness parameter B2 could be incorporated into the empirical models such as NeQuick in order to adapt them to storm situations that represent extreme cases of ionospheric weather-like conditions.

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Section: Supplementary Materialssupporting

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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B2 Thickness Parameter Response to Equinoctial Geomagnetic Storms

Migoya-Orué

Alazo-Cuartas

Kashcheyev

et al. 2021

Sensors

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“…In the bottomside F2-layer, the H parameter is called B 2bot [Leitinger et al, 2005;Radicella et al, 2021] and is analytically parameterized as:…”

Section: Slab Thickness As Modelled By Nequickmentioning

confidence: 99%

Ionospheric equivalent slab thickness ingestion into the NeQuick model

Pignalberi,

Nava,

Pietrella

et al. 2024

Annals of Geophysics

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The ionospheric equivalent slab thickness (τ), defined as the ratio of the vertical total electron content (vTEC) to the ionospheric F2-layer electron density maximum (NmF2), is a parameter providing useful information on the shape of the vertical electron density profile. However, the use of this information is of difficult practical application in empirical ionosphere models, such as the NeQuick model, because by design they do not explicitly include τ as a modelling parameter. In this work, we investigated the opportunity of using measured τ values to improve the empirical modelling of the ionosphere vertical electron density profile by NeQuick. Measured τ values were obtained through NmF2 observations and vTEC measurements obtained between 2001 and 2019 by an ionosonde and a ground-based GNSS receiver, respectively, co-located at Rome ionospheric station (41.8° N, 12.5° E; Italy). NeQuick τ was obtained as the ratio between modelled NmF2 and vTEC values, the latter obtained by integration of the vertical profile. As a first step, τ values modelled by NeQuick were compared with corresponding values measured at Rome station to highlight diurnal, seasonal, and solar activity differences. Then, measured τ values were ingested in NeQuick through a three-parameter assimilation procedure which first assimilate F2-layer peak characteristics to constrain the F2-layer anchor point, and then assimilate vTEC to optimize the F2-layer shape through the NeQuick F2-layer thickness parameter, namely B2bot. The assimilation procedure provides information on how the NeQuick B2bot has to be modified to match measured τ values, and then on how the shape of the F2-layer profile has to be changed accordingly. Our results highlight that, in many cases, the NeQuick B2bot has to be increased to match observations, which has implications on the modelling of the NeQuick bottomside and topside effective scale heights.

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“…Obtaining this new analytical formulation for H 0 , referred to as H 0,corr , was possible by constraining the NeQuick topside formulation to the characteristics of the F2-layer peak (hmF2 and the absolute maximum of electron density of the F2 layer, NmF2), as outlined by the International Reference Ionosphere UPdate (IRI UP) method across the European region [36,37], and to the electron density measurements obtained by Swarm satellites [38,39]. Since the original NeQuick models H 0 as a function of the bottomside thickness parameter [40,41], it exhibits a strong coupling between the bottomside and the topside part of the ionosphere, which in some cases causes inaccurate results [33,42,43]. The new formulation H 0,corr , also based on in-situ measurements, improved the performance of the NeQuick topside representation at middle latitudes [35,44] and low latitudes [45,46].…”

Section: Introductionmentioning

confidence: 99%

An Update of the NeQuick-Corr Topside Ionosphere Modeling Based on New Datasets

Pezzopane,

Pignalberi,

Pietrella

et al. 2024

Atmosphere

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A new analytical formula for H0, one of the three parameters (H0, g, and r) on which the NeQuick model is based to describe the altitude profile of the electron density above the F2-layer peak height hmF2, has recently been proposed. This new analytical representation of H0, called H0,corr, relies on numerical grids based on two different types of datasets. On one side, electron density observations by the Swarm satellites over Europe from December 2013 to September 2018, and on the other side, IRI UP (International Reference Ionosphere UPdate) maps over Europe of the critical frequency of the ordinary mode of propagation associated with the F2 layer, foF2, and hmF2, at 15 min cadence for the same period. The new NeQuick topside representation based on H0,corr, hereafter referred to as NeQuick-corr, improved the original NeQuick topside representation. This work updates the numerical grids of H0,corr by extending the underlying Swarm and IRI UP datasets until December 2021, thus allowing coverage of low solar activity levels, as well. Moreover, concerning Swarm, besides the original dataset, the calibrated one is considered, and corresponding grids of H0,corr calculated. At the same time, the role of g is investigated, by considering values different from the reference one, equal to 0.125, currently adopted. To understand what are the best H0,corr grids to be considered for the NeQuick-corr topside representation, vertical total electron content data for low, middle, and high latitudes, recorded from five low-Earth-orbit satellite missions (COSMIC/FORMOSAT-3, GRACE, METOP, TerraSAR-X, and Swarm) have been analyzed. The updated H0,corr grids based on the original Swarm dataset with a value for g = 0.15, and the updated H0,corr grids based on the calibrated Swarm dataset with a value for g = 0.14, are those for which the best results are obtained. The results show that the performance of the different NeQuick-corr models is reliable also for low latitudes, even though these are outside the spatial domain for which the H0,corr grids were obtained, and are dependent on solar activity.

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Thickness parameters in the empirical modeling of bottomside electron density profiles

Cited by 5 publications

References 8 publications

B2 Thickness Parameter Response to Equinoctial Geomagnetic Storms

B2 Thickness Parameter Response to Equinoctial Geomagnetic Storms

Ionospheric equivalent slab thickness ingestion into the NeQuick model

An Update of the NeQuick-Corr Topside Ionosphere Modeling Based on New Datasets

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