Comparison of observed hmF2 and IRI 2007 model with M(3000)F2 estimation of hmF2 at low solar activity for an equatorial station

Ehinlafa, O.E.; Falaiye, O A; Adeniyi, J.O.

doi:10.1016/j.asr.2010.02.018

Cited by 15 publications

(8 citation statements)

References 8 publications

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“…The IRI equation to convert M(3000)F2 to h m F2 is true under assumption that ionospheric electron concentration height-dependency is parabolic, though it is not always a good approximation. The recent research shows the significant deviations of the h m F2 model-predicted from the values obtained by Digisondes under different conditions Obrou et al, 2003;Zhang et al, 2004Zhang et al, , 2007Lee et al, 2008;Sethi et al, 2008;Ehinlafa et al, 2010;Oyeyemi et al, 2010;Magdaleno et al, 2011).…”

Section: Introductionmentioning

confidence: 97%

Global median model of the F2-layer peak height based on ionospheric radio-occultation and ground-based Digisonde observations

Шубин

2015

Advances in Space Research

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Section: Introductionmentioning

confidence: 97%

Global median model of the F2-layer peak height based on ionospheric radio-occultation and ground-based Digisonde observations

Шубин

2015

Advances in Space Research

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“…It is regularly applied in ionospheric assimilation frameworks [ Komjathy and Langley , ; Komjathy et al , ; Hernandez‐Pajares et al , ; Bust et al , ; Schmidt et al , ; Zeilhofer et al , ; Pezzopane et al , ; Galkin et al , ], in radar altimetry [ Ovodenko et al , ], in theoretical ring current models [ Ebihara et al , , ], and in high‐frequency (HF) communications forecasting [ Jodalen et al , ; Settimi et al , ; Athieno et al , ]. While several studies speak to the accuracy of the IRI at midlatitude and low latitude [ Sethi et al , ; Ehinlafa et al , ; Ezquer et al , ; Bilitza et al , ; Wichaipanich et al , ], the same cannot necessarily be said for its application to high‐latitude regions, where transport and particle precipitation events dominate ionospheric variability for large portions of the year [ Carlson , ; MacDougall and Jayachandran , ; Jayachandran et al , , ]. As the IRI was developed largely through the use of midlatitude and low‐latitude observations [ Bilitza et al , ], the performance of the IRI at high latitudes must be carefully assessed.…”

Section: Introductionmentioning

confidence: 99%

“…[]; however, these studies have been largely localized to the African, Indian, and South American sectors, all of which span comparable magnetic latitudes in the equatorial and low‐latitude zones. While other studies have examined the IRI's performance in the representation of individual components of the vertical electron density profile in all magnetic sectors [ Sethi et al , ; Ehinlafa et al , ; Ezquer et al , ; Bilitza et al , ; Wichaipanich et al , ; Themens et al , ], no research has been undertaken in assessing the IRI's TEC performance in high‐latitude regions. While Themens et al .…”

Section: Introductionmentioning

confidence: 99%

Solar activity variability in the IRI at high latitudes: Comparisons with GPS total electron content

Themens

Jayachandran

2016

JGR Space Physics

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Total electron content (TEC) measurements from 10 dual‐frequency GPS receivers in the Canadian High Arctic Ionospheric Network (CHAIN) are used to evaluate the performance of International Reference Ionosphere (IRI)‐2007 within the Canadian sector. Throughout the region, we see systematic underestimation of daytime TEC, particularly at solar maximum, where summer and equinox root‐mean‐square errors reach as high as 14 total electron content units, 1 TECU = 1016 el m−2 (TECU). It is also shown that the use of a monthly IG index, in place of the IRI's standard IG12 index, leads to an improvement in TEC specification by up to 3 TECU in the polar cap and up to 6 TECU in the subauroral region during periods of short‐term, large amplitude changes in solar activity. On diurnal timescales, variability in TEC is found to be underestimated by the IRI, during equinox periods, by up to 40% at subauroral latitudes and up to 70% in the polar cap region. During the winter, diurnal variations are overestimated by up to 40% in the subauroral region and are underestimated within the polar cap by up to 80%. Using collocated ionosonde data, we find IRI bottomside TEC to be within 1 TECU of observation with errors largest during the equinoxes. For the topside we find good agreement during the winter but significant underestimation of topside TEC by the IRI during summer and equinox periods, exceeding 6 TECU at times. By ingesting measured NmF2 into the IRI, we show that the topside thickness parameterization is the source of the bulk of the observed TEC errors.

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“…This study undertakes a thorough evaluation of key IRI parameters including F 2 peak electron density (NmF 2 ), F2 peak height (hmF 2 ), M(3000)F 2 propagation factor, bottomside thickness (B0), and topside thickness. There have been several studies that have evaluated the performance of IRI hmF 2 and NmF 2 products in midlatitude and low-latitude regions [Sethi et al, 2008;Ehinlafa et al, 2010;Ezquer et al, 2011;Bilitza et al, 2012;Wichaipanich et al, 2012], but only a select few have attempted to do so in high-latitude regions [Oyeyemi et al, 2010;Ezquer et al, 2011;Magdaleno et al, 2011;Maltseva et al, 2013], none of which have been within the polar cap or at magnetic latitudes as high as what we shall be considering in this study. The performance of the IRI bottomside thickness models has been evaluated mainly in equatorial and midlatitude regions [Sethi and Mahajan, 2002;Blanch et al, 2007;Adeniyi et al, 2008;McKinnell et al, 2009;Lee and Reinisch, 2012], where virtually no evaluation has been undertaken at high latitudes.…”

Section: Introductionmentioning

confidence: 99%

A top to bottom evaluation of IRI 2007 within the polar cap

et al. 2014

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Monthly median values of ionospheric peak height (hmF 2 ) and density (NmF 2 ), derived from ionosonde measurements at four Canadian High Arctic Ionospheric Network (CHAIN) stations situated within the polar cap and Auroral Oval, are used to evaluate the performance of the International Reference Ionosphere (IRI) 2007 empirical ionospheric model during the recent solar minimum between 2008 and 2010. This analysis demonstrates notable differences between IRI and ionosonde NmF 2 diurnal and seasonal behavior over the entire period studied, where good agreement is found during summer periods but otherwise errors in excess of 50% were prevalent, particularly during equinox periods. hmF 2 is found to be marginally overestimated during winter and equinox nighttime, while also being underestimated during summer and equinox daytime by in excess of 25%. These errors are shown to be related to significant mismodeling of the M(3000)F 2 propagation factor. The ionospheric bottomside thickness parameter (B0) is also evaluated using ionosonde measurements. It is found that both of the IRI's internal B0 models significantly misrepresent both seasonal and diurnal variations in bottomside thickness when compared to ionosonde observations, where errors at times exceed 40%. A comparison is also presented between IRI and Resolute (74.75N, 265.00E) Advanced Modular Incoherent Scatter Radar (AMISR)-derived topside thickness. It is found in this comparison that the IRI is capable of modeling ionospheric topside thickness exceptionally well during winter and summer periods but fails to represent significant diurnal variability during the equinoxes and seasonal variations.

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Comparison of observed hmF2 and IRI 2007 model with M(3000)F2 estimation of hmF2 at low solar activity for an equatorial station

Cited by 15 publications

References 8 publications

Global median model of the F2-layer peak height based on ionospheric radio-occultation and ground-based Digisonde observations

Global median model of the F2-layer peak height based on ionospheric radio-occultation and ground-based Digisonde observations

Solar activity variability in the IRI at high latitudes: Comparisons with GPS total electron content

A top to bottom evaluation of IRI 2007 within the polar cap

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