Assessment of IRI and IRI‐Plas models over the African equatorial and low‐latitude region

Adebiyi, S.J.; Adimula, I. A.; Oladipo, O.A.; Joshua, B.W.

doi:10.1002/2016ja022697

Cited by 24 publications

(15 citation statements)

References 27 publications

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“…(2018) compared the performance of IRI-Plas with other ionospheric models such as the IRI and NeQuick-2 models in the African region. In Adebiyi et al., 2016a, Adebiyi et al., 2016b, the predictions of the IRI-Plas and the three topside options of the IRI models were found to show latitudinal and seasonal trends. In other words, IRI-Plas model was found to perform better than the IRI in months and seasons where the IRI model underestimates TEC.…”

Section: Introductionmentioning

confidence: 98%

“…Studies to validate the IRI model at different regions have been conducted by different authors e.g. Adebiyi et al., 2014; Adebesin et al.,2014; Adebiyi et al., 2016a, b; Grynyshyna-Poliuga et al.,2015; Scidá et al., 2012, Olawepo et al., 2017 etc. Results from some of these studies have revealed discrepancies in the performance of the model, some of which have been attributed to its inability to account for the plasmaspheric contribution to the ionospheric total electron content (TEC) e.g.…”

Section: Introductionmentioning

confidence: 99%

“…Bolaji et al., 2017; Adebiyi et al., 2016a, b, 2017; Gulyaeva, 2011; Maltseva et al, 2013; Zakharenkova et al., 2015; Gordiyenko et al., 2018; Okoh et al., 2018; Ezquer et al., 2017). Adebiyi et al., 2016a, Adebiyi et al., 2016b, Bolaji et al. (2017) and Okoh et al.…”

Section: Introductionmentioning

confidence: 99%

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Storm time IRI-Plas model forecast for an African equatorial station

Adebiyi

Ikubanni

Adebesin

et al. 2019

Heliyon

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The limitation of ionospheric models in describing short-term ionospheric events has led to the development of data assimilative models e.g. the International Reference Ionosphere extended to Plasmasphere (IRI-Plas) model . This paper compares the IRI-Plas derived total electron content (TEC), the peak height (hmF2) and critical frequency (foF2) of the F2-layer with those obtained from Global Positioning System (GPS) receiver's and Digisonde Precision Sounder (DPS-4) measurements over Ilorin (Geog. Lat. 8.50 o N; Long. 4.50 o E, dip: – 7.9 o ) during geomagnetic storm days. The model estimation was done by assimilation of Ionosonde foF2 and TEC derived from GPS (GPS-TEC) and Global Ionospheric Map (GIM-TEC) into the model code. In order to study the effect of data assimilation on the model's representation, the “no input” option of the model was used as reference. The result shows that with the exception of the foF2 assimilation mode, all the options generally reproduced TEC quite well for all the storm days considered. Overall, the model adjusted with GPS-TEC gives the best prediction of TEC as it reduced the prediction error of TEC by a multiple of up to three compared to using the GIM-TEC. Also, all the options failed to reproduce the storm induced prominent features in the storm-time features of foF2 and hmF2. In other word, assimilation with the TEC does not generally improve the storm-time predictions of foF2 and hmF2 at the station. Consequently, for storm-time estimation of the F2-layer peak parameters, the ‘no input’ representation of the model is more valid at this station.

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Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

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Storm time IRI-Plas model forecast for an African equatorial station

Adebiyi

Ikubanni

Adebesin

et al. 2019

Heliyon

View full text Add to dashboard Cite

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“…In addition, Tariku (2019) noted that none of the versions of the IRI model are able to adequately estimate the variation of the VTEC over the equatorial and low latitude region (Ethiopia). Moreover, Adebiyi et al (2016), Ezquer et al (2017) and Zakharenkova et al (2015) discussed that the IRI‐Plas 2015 model generally showed overestimations as compared to the IRI 2012 model over the African equatorial and magnetic low latitude regions. Okoh et al (2018) also noted that the NeQuick 2 model tends to underestimate the VTEC variations during the high solar activity years.…”

Section: Introductionmentioning

confidence: 99%

Comparison of Performance of the IRI 2016, IRI‐Plas 2017, and NeQuick 2 Models During Different Solar Activity (2013–2018) Years Over South American Sector

Tariku

2020

Radio Science

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This study mainly focuses on the prediction of the variability of the vertical total electron content (VTEC) and validation of the new versions of the International Reference Ionosphere (IRI 2016), IRI extended to the plasmasphere (IRI‐Plas 2017), and NeQuick 2 models over the equatorial anomaly region during 2013–2018. The Global Positioning System (GPS)‐derived VTEC data inferred from the South American equatorial region during the relatively high (2013–2014), descending (2015–2016), and low (2017–2018) solar activity years have been considered as measurements to validate the models. The modeled (IRI 2016, IRI‐Plas 2017, and NeQuick 2) VTEC values are generally larger than the GPS‐derived VTEC values, with the highest overestimation being illustrated by the IRI‐Plas 2017 model. Small underestimations are also observed in employing the IRI 2016 and NeQuick 2 models, especially when the solar activity increases. The highest root‐mean‐square Deviations (RMSDs) reaching up to 10 TEC units (TECU) is observed in some hours while using the IRI‐Plas 2017 model during the high solar activity years. RMSDs less than 5 TECU are also observed on most of the hours while utilizing the model during all solar activity years. However, RMSD values less than 2 TECU (while using the NeQuick 2 model) and less than 1 TECU (while using the IRI 2016 model) are seen on most of the hours during 2013–2018. This shows that the performance of the IRI 2016 and NeQuick 2 is better than the IRI‐Plas 2017 with the IRI 2016 model consistently revealing the best in all solar activity years.

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“…The IRI model (and the IRI‐Plas as one of the extensions to the plasmasphere) has been reinstated by ISO (ISO 16457:2014) as given in https://www.iso.org/standard/61556.html in 2014. It has been shown in the literature that the assimilation of TEC into the model improves the representation of current ionospheric state significantly (Adebiyi et al, , ; Bolaji et al, ; Ezquer et al, ; Maltseva et al, , ; Panda et al, ; Zakharenkova et al, ). The IRI‐Plas model is available at http://ftp.izmiran.ru/pub/izmiran/SPIM/ as a FORTRAN code.…”

Section: Introductionmentioning

confidence: 99%

Performance of Solar Proxy Options of IRI‐Plas Model for Equinox Seasons

2018

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International Reference Ionosphere (IRI) is the most acclaimed climatic model of the ionosphere. Since 2009, the range of the IRI model has been extended to the Global Positioning System (GPS) orbital height of 20,000 km in the plasmasphere. The new model, which is called IRI extended to Plasmasphere (IRI‐Plas), can input not only the ionosonde foF2 and hmF2 but also the GPS‐total electron content (TEC). IRI‐Plas has been provided at http://www.ionolab.org, where online computation of ionospheric parameters is accomplished through a user‐friendly interface. The solar proxies that are available in IRI‐Plas can be listed as sunspot number (SSN1), SSN2, F10.7, global electron content (GEC), TEC, IG, Mg II, Lyman‐α, and GEC_RZ. In this study, ionosonde foF2 data are compared with IRI‐Plas foF2 values with the Consultative Committee International Radio (CCIR) and International Union of Radio Science (URSI) model choices for each solar proxy, with or without the GPS‐TEC input for the equinox months of October 2011 and March 2015. It has been observed that the best fitting model choices in Root Mean Square (RMS) and Normalized RMS (NRMS) sense are the Jet Propulsion Laboratory global ionospheric maps‐TEC input with Lyman‐α solar proxy option for both months. The input of TEC definitely lowers the difference between the model and ionosonde foF2 values. The IG and Mg II solar proxies produce similar model foF2 values, and they usually are the second and third best fits to the ionosonde foF2 for the midlatitude ionosphere. In high‐latitude regions, Jet Propulsion Laboratory global ionospheric map‐TEC inputs to IRI‐Plas with Lyman‐α, GEC_RZ, and TEC solar proxies are the best choices. In equatorial region, the best fitting solar proxies are IG, Lyman‐α, and Mg II.

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Assessment of IRI and IRI‐Plas models over the African equatorial and low‐latitude region

Cited by 24 publications

References 27 publications

Storm time IRI-Plas model forecast for an African equatorial station

Storm time IRI-Plas model forecast for an African equatorial station

Comparison of Performance of the IRI 2016, IRI‐Plas 2017, and NeQuick 2 Models During Different Solar Activity (2013–2018) Years Over South American Sector

Performance of Solar Proxy Options of IRI‐Plas Model for Equinox Seasons

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