On the variations in equatorial and low-latitude GPS-TEC and assessment of NeQuick-2, IRI-2016 and IRI-2020 models in the African longitude during solar cycle 24–25 - 2025
On the variations in equatorial and low-latitude GPS-TEC and assessment of NeQuick-2, IRI-2016 and IRI-2020 models in the African longitude during solar cycle 24–25
GPS; Ionosphere; IRI-2016; IRI-2020, NeQuick-2; Solar cycles 24–25; Total Electron Content; Equatorial and low latitudes; GPS TEC; International reference ionosphere-2016; International reference ionosphere-2020, nequick-2; International reference ionospheres; Ionospheric model; Solar cycle; Solar cycle 24–25; Total electron content; Aerospace Engineering; Astronomy and Astrophysics; Geophysics; Atmospheric Science; Space and Planetary Science; Earth and Planetary Sciences (all)
Abstract :
[en] Ionospheric models play a crucial role in understanding, prediction, and mitigation of the effects of ionospheric variability on a wide range of technological and scientific applications relying on space-based services. Conversely, the models need to be routinely updated with newer datasets and specifications to account for the regional discrepancies in the changing ionospheric conditions due to various dominant localized physical and chemical processes. Although there have been ongoing improvements to the extensively utilized empirical model known as the International Reference Ionosphere (IRI), the newly emerged version (IRI-2020) needs to undergo global testing. In this research, we carried out diurnal and seasonal variations in GPS-TEC and the assessment of some ionospheric models such as IRI-2016 and its recently updated version (IRI-2020), alongside the NeQuick-2 model at 2 stations each in the East, West and South in the equatorial and low-latitude African longitudes during different phases of solar cycles 24–25 (2016 – 2021). Also, we carried out statistical analysis between GPS-TEC and the ionospheric models using Root Mean Square Error (RMSE) and Mean Absolute Error (MAE), in order to show the model with the best forecasting capability in the African region. Diurnal, seasonal and solar cycle variations in GPS-TEC, NeQuick-2, IRI-2016 and IRI-2020 were observed, showing higher magnitudes in the West, followed by the East in close range and least in the Southern sector of the African longitudes. TEC Variations in some sectors in the African longitudes show a consistent trend in this research. More importantly, there are observed regional differences within the African longitudes owing to the wider coverage of landmass in the equatorial and low latitudes. However, TEC variations in the Northern sector of Africa are not included in the present research. From our observation, NeQuick-2 and IRI-2016 models either underestimate or overestimate GPS-TEC during different phases of the solar cycles at the three sectors in the African longitudes, whereas IRI-2020 shows mostly underestimating characteristics at the three sectors irrespective of solar activity conditions during the study period. Nevertheless, the underestimation or overestimation of NeQuick-2 and IRI-2016, and the underestimation of IRI-2020 are reflected in the RMSE and MAE values. Regrettably, the predictions from IRI-2020 model are not satisfactory at any of the three sectors in the African longitudes and prompt attention of the modeling community for further investigations towards possible refinements in the model specifications.
Disciplines :
Physics
Author, co-author :
Ogwala, Aghogho; Department of Physics, Eko University of Medicine and Health Sciences, Lagos, Nigeria
Akinbuli, Feyisara Fehintoluwa; Department of Physics, Lagos State University, Ojo, Lagos, Nigeria
Panda, Sampad Kumar; Department of Electronics and Communication Engineering, K L Deemed to be University, Guntur, India
Jamjareegulgarn, Punyawi; Department of Electrical Engineering, Faculty of Engineering, King Mongkut's Institute of Technology Ladkrabang, Prince of Chumphon Campus, Chumphon, Thailand
Siddiqui, Md Irfanul Haque; Mechanical Engineering Department, College of Engineering, King Saud University, Riyadh, Saudi Arabia
Kayode, Yusuf Olanrewaju ; Department of Physics, Lagos State University, Ojo, Lagos, Nigeria
Ashraf, Intesaaf ; Université de Liège - ULiège > Département de physique > Physique statistique
Somoye, Emmanuel Olufemi; Department of Physics, Lagos State University, Ojo, Lagos, Nigeria
Language :
English
Title :
On the variations in equatorial and low-latitude GPS-TEC and assessment of NeQuick-2, IRI-2016 and IRI-2020 models in the African longitude during solar cycle 24–25
TSRI - Thailand Science Research and Innovation KSU - King Saud University
Funding text :
The authors extend their appreciation to the Deanship of Scientific Research, Researchers Supporting Project number (RSPD2024R999), King Saud University, Riyadh, Saudi Arabia. PJ acknowledges the financial support for this research from Fundamental Fund (FF67) of the Thailand Science Research and Innovation Fund Grant Number: RE-KRIS/FF67/008. The authors acknowledge Gopi Krishna Seemala for providing the GPS-TEC analysis application program to conduct this research. The authors acknowledge UNAVCO for making TEC data available through www.unavco.com, the IRI working group for making IRI-2016 and IRI-2020 available online (https://kauai.ccmc.gsfc.nasa.gov/instantrun/iri/), and the NeQuick-2 model working group of the ICTP through http://tict4d.ictp.it/nequick2/nequick-2-web-model/. Finally, the authors like to thank Dr Oluwole J. Oyedokun for providing Fig. 1 of the present manuscript.The authors extend their appreciation to the Deanship of Scientific Research, Researchers Supporting Project number (RSPD2024R999), King Saud University, Riyadh, Saudi Arabia. PJ acknowledges the financial support for this research from Fundamental Fund (FF67) of the Thailand Science Research and Innovation Fund Grant Number: RE-KRIS/FF67/008. The authors acknowledge Gopi Krishna Seemala for providing the GPS-TEC analysis application program to conduct this research. The authors acknowledge UNAVCO for making TEC data available through www.unavco.com, the IRI working group for making IRI-2016 and IRI-2020 available online (https://kauai.ccmc.gsfc.nasa.gov/instantrun/iri/), and the NeQuick-2 model working group of the ICTP through http://tict4d.ictp.it/nequick2/nequick-2-web-model/. Finally, the authors like to thank Dr Oluwole J. Oyedokun for providing Figure 1 of the present manuscript.
A, E., Ridley, A.J, Zhang, D., Xiao, Z., 2012. Analyzing the hemispheric asymmetry in the thermospheric density response to geomagnetic storms. J. Geophys. Res.: Space Phys. 117, A08317. doi:10.1029/2011JA017259.
Adewale, A.O., Oyeyemi, E.O., Adeloye, A., Adeniyi, J.O., Oladipo, O.A., Comparison of total electron content predicted using the IRI-2007 model with GPS observations over Lagos, Nigeria. Indian J. Radio Space Phys. 40:1 (2011), 21–25.
Akala, A.O., Somoye, E.O., Adewale, A.O., Ojutalayo, E.W., Karia, S.P., Idolor, R.O., Doherty, P.H., Comparison of GPS-TEC observations over Addis Ababa with IRI-2012 model predictions during 2010–2013. Adv. Space Res. 56:8 (2015), 1686–1698, 10.1016/j.asr.2015.07.017.
Alcay, S., Oztan, G., Selvi, H.Z., Comparison of IRI_PLAS and IRI_2012 model predictions with GPS-TEC measurements in different latitude regions. Annales Geophysics, 60(5), 2017, G0549, 10.4401/ag-7311.
Arikan, F., Shukurov, S., Tuna, H., Arikan, O., Gulyaeva, T.L., Performance of GPS slant total electron content and IRI-Plas-STEC for days with ionospheric disturbance. Geod. Geodyn. 7:1 (2016), 1–10, 10.1016/j.geog.2015.12.009.
Bagiya, M.S., Joshi, H.P., Iyer, K.N., Aggarwal, M., Ravindran, S., Pathan, B.M., TEC variations during low solar activity period (2005–2007) near the Equatorial Ionospheric Anomaly Crest region in India. Ann. Geophys. 27:3 (2009), 1047–1057 https://dio.org/10.5194.angeo-27-1047-2009.
Balan, N., Bailey, G. J., Nair, R.B., 1991. Solar and magnetic activity effects on the latitudinal variations of nighttime TEC enhancement. Annales Geophysicae, 9, 60-69. ISSN 0939-4176.
Balan, N., Liu, L., Le, H., A brief review of the equatorial ionization anomaly and ionospheric irregularities. Earth Planet. Phys. 2:4 (2018), 257–275, 10.26464/epp2018025.
Bhuyan, P.K., Borah, R.R., TEC derived from GPS network in India and comparison with the IRI. Adv. Space Res. 39:5 (2007), 830–840, 10.1016/j.asr.2006.12.042.
Bilitza, D., IRI the International Standard for the Ionosphere. Adv. Radio Sci. 16 (2018), 1–11, 10.5194/ars-16-1-2018.
Bilitza, D., Altadill, D., Truhlik, V., Shubin, V., Galkin, I., Reinisch, B., Huang, X., International Reference Ionosphere 2016: From ionospheric climate to real-time weather predictions. Space Weather 15:2 (2017), 418–429, 10.1002/2016SW001593.
Bilitza, D., Pezzopane, M., Truhlik, V., Altadill, D., Reinisch, B.W., Pignalberi, A., The International Reference Ionosphere model: A review and description of an ionospheric benchmark. Reviews of Geophysics, 60, 2022, e2022RG000792, 10.1029/2022RG000792.
Bolaji, O.S., Oyeyemi, E.O., Adewale, A.O., Wu, Q., Okoh, D., Doherty, P.H., Jidele, P.A., Assessment of IRI-2012, NeQuick-2 and IRI-Plas 2015 models with observed equatorial ionization anomaly in Africa during 2009 sudden stratospheric warming event. J. Atmos. Sol. Terr. Phys. 164 (2017), 203–214, 10.1016/j.jastp.2017.08.025.
Chaurasiya, S.K., Patel, K., Kumar, S., Singh, A.K., Analysis of GPS-TEC and IRI model over equatorial and EIA stations during solar cycle 24. Adv. Space Res. 72:11 (2023), 4882–4895, 10.1016/j.asr.2023.09.014.
de Abreu, A., Martin, I., de Jesus, R., Bolzan, M., Venkatesh, K., Fagundes, P., Kumar, S., Comparison of GPS-TEC measurements with IRI2012-TEC predictions in the Brazilian sector during the unusual solar minimum 2009. Ann. Geophys., 60(3), 2017, 10.4401/ag-7300.
Eyelade, A., Adewale, A.O., Akala, A., Bolaji, O., Rabiu, A., Studying the variability in the diurnal and seasonal variations in GPS total electron content over Nigeria. Ann. Geophys. 35 (2017), 701–710, 10.5194/angeo-35-701-2017.
Ezquer, R.G., Scidá, L.A., Migoya Orué, Y., Nava, B., Cabrera, M.A., Brunini, C., NeQuick 2 and IRI Plas VTEC predictions for low latitude and South American sector. Adv. Space Res. 61:7 (2018), 1803–1818, 10.1016/j.asr.2017.10.003.
He, R., Li, M., Zhang, Q., Zhao, Q., A Comparison of a GNSS-GIM and the IRI-2020 model over China under different ionospheric conditions. Space Weather, 21, 2023, e2023SW003646, 10.1029/2023SW003646.
Karia, S.P., Patel, N.C., Pathak, K.N., Comparison of GPS based TEC measurements with the IRI-2012 model for the period of low to moderate solar activity (2009–2012) at the crest of equatorial anomaly in Indian region. Adv. Space Res. 55:8 (2015), 1965–1975, 10.1016/j.asr.2014.10.026.
Liu, L., Wang, W., Ning, B., Pirog, O.M., Kurkin, V.I., Solar activity variations of the ionospheric peak electron density. J. Geophys. Res., 111, 2006, A08304, 10.1029/2006JA011598.
Liu, L., Wang, W., Chen, Y., Le, H., Solar activity effects on the ionosphere: A brief review, Space Physics and Space Weather Geophysics. Chinese Science Bulletin 56:12 (2011), 1202–1211 doi: 10.1007.s11434-010-4226-9.
Maltseva, O.A., Mozhaeva, N.S., Poltavsky, O.S., Zhbankov, G.A., Use of TEC global maps and the IRI model to study ionospheric response to geomagnetic disturbances. Adv. Space Res. 49:6 (2012), 1076–1087, 10.1016/j.asr.2012.01.005.
Maltseva, O., Zhbankov, G., Mozhaeva, N., Advantages of the new model of IRI (IRI-Plas) to simulate the ionospheric electron density: Case of the European area. Adv. Radio Sci. 11 (2013), 307–311, 10.5194/ars-11-307-2013.
Marew, H., Agmos, A., Mersha, T., Performance evaluation for vertical TEC predictions over the East Africa and South America: IRI-2016 and IRI-2020. Adv. Space Res. 73:1 (2023), 698–715, 10.1016/j.ars.2023.09.055.
Nava, B., Coisson, P., Radicella, S.M., A new version of the NeQuick ionosphere electron density model. J. Atmos. Sol. Terr. Phys. 70:15 (2008), 1856–1862, 10.1016/J.jastp.2008.01.015.
Obafaye, A., Okoh, D., Adewale, A., Udochukwu, B., Rabiu, A., et al. Comparison of IRI-01cor, IRI-Plas 2017, Ne Quick-2 and NIGTEC models with GPS-TEC measurements over Nigeria. Sun and Geosphere 14:2 (2019), 147–160, 10.31401/SunGeo.2019.02.07.
Ogwala, A., Somoye, E.O., Panda, S.K., Ogunmodimu, O., Onori, E., Sharma, S.K., Okoh, D., Oyedokun, O., Total electron content at equatorial and low-, middle- and high-latitudes in African longitude sector and its comparison with IRI-2016 and IRI-PLAS 2017 models. Adv. Space Res. 68:5 (2021), 2160–2176, 10.1016/j.asr.2020.07.013.
Ogwala, A., Oyedokun, O., Olumodimu, O., Akala, A., Ashraf, M., Jamjareegulgarn, P., Panda, S.K., Longitudinal Variations in Equatorial Ionospheric TEC from GPS, Global Ionosphere Map and International Reference Ionosphere-2016 during the Descending and Minimum Phases of Solar Cycle 24. Universe 8 (2022), 1–24, 10.3390/universe8110575.
Okoh, D., Eze, A., Adedoja, O., Okere, B., Okeke, P., A comparison of IRI-TEC predictions with GPS-TEC measurements over Nsukka, Nigeria. Space Weather, 10, 2012, 10002, 10.1029/2012SW000830.
Okoh, D., Owolabi, O., Ekechukwu, C., Folarin, O., Arhiwo, G., Agbo, J., Bolaji, S., Rabiu, B., A regional GNSS-VTEC model over Nigeria using neural networks: A novel approach. Geod. Geodyn. 7:1 (2016), 19–31, 10.1016/j.geog.2016.03.003.
Okoh, D., Onwuneme, S., Seemala, G., Jin, S., Rabiu, B., Nava, B., Uwamahoro, J., Assessment of the NeQuick-2 and IRI-Plas 2017 models using global and long-term GNSS measurements. J. Atmos. Sol. Terr. Phys. 170 (2018), 1–10, 10.1016/j.jastp.2018.02.006.
Okoh, D., Habarulema, J.B., Rabiu, B., Seemala, G., Wisdom, J.B., Olwendo, J., et al. Storm-time modeling of the African regional ionospheric total electron content using artificial neural networks. Space Weather, 18, 2020, e2020SW002525, 10.1029/2020SW002525.
Olawepo, A.O., Adeniyi, J.O., Oluwadare, E.J., TEC variations and IRI-2012 performance at equatorial latitudes over Africa during low solar activity. Adv. Space Res. 59:7 (2017), 1800–1809, 10.1016/j.asr.2017.01.017.
Olwendo, O.J., Baki, P., Cilliers, P.J., Mito, C., Doherty, P., Comparison of GPS TEC variations with IRI-2007 TEC prediction at equatorial latitudes during a low solar activity (2009–2011) phase over the Kenyan region. Adv. Space Res. 52:10 (2013), 1770–1779, 10.1016/j.asr.2012.08.001.
Panda, S.K., Haralambous, H., Mefe, M., Dabbakuti, J.R.K.K., Tariku, Y.A., Ionospheric ans plasmaspheric electron contents from space-time collated digisonde, COSMIC, GPS observations and model assessments. Acta Astronaut. 179 (2021), 619–635, 10.1016/j.actaastro.2020.12.005.
Rabiu, A.B., Adewale, A.O., Abdulrahim, R.B., Oyeyemi, E.O., TEC derived from some GPS stations in Nigeria and comparison with the IRI and NeQuick models. Adv. Space Res. 53:9 (2014), 1290–1303, 10.1016/j.asr.2014.02.009.
Rama Rao, P.V.S., Niranjan, K., Prasad, D.S.V.V.D., Gopi Krishna, S., Uma, G., On the validity of the ionospheric pierce point (IPP) altitude of 350 km in the Indian equatorial and low-latitude sector. Annales Geophy. 24:8 (2006), 2159–2168, 10.5194/angeo-24-2159-2006.
Reddybattula, K.D., Panda, S.K., Ansari, K., Peddi, V.S.R., Analysis of ionospheric TEC from GPS, GIM and global ionosphere models during moderate, strong, and extreme geomagnetic storms over Indian region. Acta Astronaut. 161 (2019), 283–292, 10.1016/j.actaastro.2019.05.042.
Rishbeth, H., Müller-Wodarg, I.C.F., Zou, L., Fuller-Rowell, T.J., Millward, G.H., Moffett, R.J., Aylward, A.D., Annual and semiannual variations in the ionospheric F2-layer: II. Physical Discussion. Ann. Geophys. 18:8 (2000), 945–956, 10.1007/s00585-000-0945-6.
Sahu, S., Pal, A., Choudhary, R.K., Jain, A., Jain, S., Nighttime enhancements in the VTEC at anomaly crest region Bhopal: Solar and magnetic activity effects. Adv. Space Res. 66:10 (2020), 2289–2301, 10.1016/j.asr.2020.08.016.
Seemala, G.K., Katual, I., Kapil, P., Vichare, G., Seasonal and solar activity dependence of TEC over Bharati station. Antarctica. Polar Science, 38(2003), 2023, 101001, 10.1016/j.polar.2023.101001.
Seemala, G., Valladares, C., Statistics of total electron content depletions observed over the South American continent for the year 2008. Radio Sci. 46:05 (2011), 1–14, 10.1029/2011RS004722.
Sharma, S.K., Ansari, K., Panda, S.K., Analysis of Ionospheric TEC Variation over Manama, Bahrain, and Comparison with IRI-2012 and IRI-2016 Models. Arab. J. Sci. Eng. 43 (2018), 3823–3830, 10.1007/s13369-018-3128-z.
Sherif, A., Rabah, M., Mousa, A., Zaki, A., Sedeek, A., Assessing the performance of IRI-2016 and IRI-2020 models using COSMIC-2 GNSS radio occultation TEC data under different magnetic activities over Egypt. Journal of Applied Geodesy 18:1 (2024), 163–176, 10.1515/jag-2023-0068.
Shimeis, A., Amory-Mazaudier, C., Fleury, R., Mahrous, A.M., Hassan, A.F., Transient Variations of Vertical Total electron content over some African stations from 2002–2012. Adv. Space Res. 54:11 (2014), 2159–2171, 10.1016/j/asr.2014.07.038.
Torr, D.G., Torr, M.R., Richards, P.G., Causes of F region winter anomaly. Geophys. Res. Lett. 7:5 (1980), 301–304, 10.1029/GL007i005p00301.
Trivedi, R., Jain, S., Jain, A., Gwal, A.K., Solar and magnetic control on night-time enhancement in TEC near the crest of the Equatorial Ionization Anomaly. Adv. Space Res. 51:1 (2013), 61–68, 10.1016/j.asr.2012.08.016.
Willmott, C.J., Matsuura, K., 2005. Advantages of the mean absolute error (MAE) over the root mean square error (RMSE) in assessing average model performance. Climate Research 30(1), 79–82. doi: 103354/cr030079.
Yao, J.N., Nava, B., Obrou, O.K., Radicella, S.M., Validation of NeQuick 2 model over West African equatorial region using GNSS-derived Total Electron Content data. J. Atmos. Sol. Terr. Phys. 181 (2018), 1–9, 10.1016/j.jastp.2018.10.001.
Zakharenkova, I.E., Cherniak, I.V., Krankowski, A., Shagimuratov, I.I., Vertical TEC representation by IRI 2012 and IRI Plas models for European midlatitudes. Adv. Space Res. 55:8 (2015), 2070–2076, 10.1016/j.asr.2014.07.027.
Zhong, J., Lei, J., Wang, W., Burns, A.G., Yue, X., Dou, X., Longitudinal variations of topside ionospheric and plasmaspheric TEC. J. Geophys. Res. Space Phys. 122:6 (2017), 6737–6760, 10.1002/2017JA024191.
