Solar-Terrestrial Physics Solar-Terrestrial Physics Solar-Terrestrial Physics 2500-0535 89279 10.12737/stp-112202507 Results of current research Results of current research Results of current research Regional electron content responses to geomagnetic events at high, middle, and equatorial latitudes obtained by superposed epoch method using AE index Regional electron content responses to geomagnetic events at high, middle, and equatorial latitudes obtained by superposed epoch method using AE index https://orcid.org/0000-0002-0847-3553 Ратовский Константин Геннадьевич Ratovsky Konstantin Gennadyevich ratovsky@iszf.irk.ru

кандидат физико-математических наук;

candidate of physical and mathematical sciences;

 Клименко Максим Владимирович Klimenko Maksim Vladimirovich maksim.klimenko@mail.ru

кандидат физико-математических наук;

candidate of physical and mathematical sciences;

 Веснин Артем Михайлович Vesnin Artem Mihaylovich artem_vesnin@iszf.irk.ru Белюченко Куприян Владимирович Belyuchenko Kupriyan Vladimirovich kdei@list.ru Институт солнечно-земной физики СО РАН Иркутск Россия Institute of Solar-Terrestrial Physics SB RAS Irkutsk Russian Federation Западное отделение ИЗМИРАН Калининград Россия WD IZMIRAN Kaliningrad Russian Federation Балтийский федеральный университет имени И. Канта Калининград Россия I. Kant Baltic Federal University Kaliningrad Russian Federation Институт солнечно-земной физики СО РАН Иркутск Россия Institute of Solar Terrestrial Physics SB RAS Irkutsk Russian Federation Балтийский федеральный университет им. Иммануила Канта Immanuel Kant Baltic Federal University 26 06 2025 26 06 2025 11 2 69 77 02 10 2024 02 04 2025 https://zh-szf.ru/en/nauka/article/89279/view

The paper studies statistical patterns of regional electron content responses to geomagnetic events at high, middle, and equatorial latitudes. The regional electron content is the total electron content averaged over all longitudes in a given latitudinal zone. The statistical analysis includes the following: 1) identification of geomagnetic events based on the AE index and calculation of “reference” geomagnetic storms; 2) calculation of the regional electron content (REC) for five latitudinal zones (equatorial zone, mid-latitude zones of the Northern and Southern hemispheres, and high-latitude zones of the Northern and Southern hemispheres); 3) calculation of REC disturbances (ΔREC), which are relative (percentage) deviations of the observed values, from the 27-day running mean of REC and 4) obtaining the “reference” ionospheric response in the form of the dynamics of average ΔREC, obtained by the superposed epoch method. The superposed epoch method is implemented with the hourly resolution and key moments corresponding to the AE index maximum. Compared with our previous statistical analysis, implemented with daily resolution based on geomagnetic storm identification by the Dst index, the new method leads to a significant increase in the amplitude and the time-focusing of the response. The seasonal behavior of ionospheric responses was analyzed for correspondence to the thermospheric storm concept. The responses of the equatorial and mid-latitude zones of the Southern Hemisphere fit the thermospheric storm concept. In the mid-latitude zone of the Northern Hemisphere, there are a number of exceptions. The responses of the high-latitude zone show the need to take into account the mechanisms behind the formation of positive disturbances, which are absent in the thermospheric storm concept

The paper studies statistical patterns of regional electron content responses to geomagnetic events at high, middle, and equatorial latitudes. The regional electron content is the total electron content averaged over all longitudes in a given latitudinal zone. The statistical analysis includes the following: 1) identification of geomagnetic events based on the AE index and calculation of “reference” geomagnetic storms; 2) calculation of the regional electron content (REC) for five latitudinal zones (equatorial zone, mid-latitude zones of the Northern and Southern hemispheres, and high-latitude zones of the Northern and Southern hemispheres); 3) calculation of REC disturbances (ΔREC), which are relative (percentage) deviations of the observed values, from the 27-day running mean of REC and 4) obtaining the “reference” ionospheric response in the form of the dynamics of average ΔREC, obtained by the superposed epoch method. The superposed epoch method is implemented with the hourly resolution and key moments corresponding to the AE index maximum. Compared with our previous statistical analysis, implemented with daily resolution based on geomagnetic storm identification by the Dst index, the new method leads to a significant increase in the amplitude and the time-focusing of the response. The seasonal behavior of ionospheric responses was analyzed for correspondence to the thermospheric storm concept. The responses of the equatorial and mid-latitude zones of the Southern Hemisphere fit the thermospheric storm concept. In the mid-latitude zone of the Northern Hemisphere, there are a number of exceptions. The responses of the high-latitude zone show the need to take into account the mechanisms behind the formation of positive disturbances, which are absent in the thermospheric storm concept

 ionospheric response geomagnetic storm statistics superposed epoch method AE index ionospheric response geomagnetic storm statistics superposed epoch method AE index The research was financially supported by the Russian Science Foundation (Grant No. 23-27-00213) The research was financially supported by the Russian Science Foundation (Grant No. 23-27-00213)

Araujo-Pradere E.A., Fuller-Rowell T.J., Codrescu M.V., Bilitza D. Characteristics of the ionospheric variability as a function of season latitude local time and geomagnetic activity. Radio Sci. 2005, vol. 40, RS5009. DOI: 10.1029/2004RS003179. Araujo-Pradere E.A., Fuller-Rowell T.J., Codrescu M.V., Bilitza D. Characteristics of the ionospheric variability as a function of season latitude local time and geomagnetic activity. Radio Sci. 2005, vol. 40, RS5009. DOI: 10.1029/2004RS003179. Astafyeva E., Zakharenkova I., Förster M. Ionospheric response to the 2015 St. Patrick’s Day storm: A global multi-instrument overview. J. Geophys. Res.: Space Phys. 2015, vol. 120, no. 10, pp. 9023–9037. DOI: 10.1002/2015JA021629. Astafyeva E., Zakharenkova I., Förster M. Ionospheric response to the 2015 St. Patrick’s Day storm: A global multi-instrument overview. J. Geophys. Res.: Space Phys. 2015, vol. 120, no. 10, pp. 9023–9037. DOI: 10.1002/2015JA021629. Brjunelli B.E., Namgaladze A.A. Fizika ionosfery [Physics of the ionosphere]. Moscow, Nauka, 1988, 528 p. (In Russian). Brjunelli B.E., Namgaladze A.A. Fizika ionosfery [Physics of the ionosphere]. Moscow, Nauka, 1988, 528 p. (In Russian). Buonsanto M.J. Ionospheric Storms: A Review. Space Sci. Rev. 1999, vol. 88, no. 3-4, pp. 563–601. DOI: 10.1023/A:1005107532631. Buonsanto M.J. Ionospheric Storms: A Review. Space Sci. Rev. 1999, vol. 88, no. 3-4, pp. 563–601. DOI: 10.1023/A:1005107532631. Burešová D., Laštovička J. Pre-storm enhancements of foF2 above Europe. Adv. Space Res. 2007, vol. 39, no. 8, pp. 1298–1303. DOI: 10.1016/j.asr.2007.03.003. Burešová D., Laštovička J. Pre-storm enhancements of foF2 above Europe. Adv. Space Res. 2007, vol. 39, no. 8, pp. 1298–1303. DOI: 10.1016/j.asr.2007.03.003. da Silva R.P., Denardini C.M., Marques M.S., Resende L.C.A., Moro J., et al. Ionospheric total electron content responses to HILDCAA intervals. Ann. Geophys. 2020, vol. 38, no. 1, pp. 27–34. DOI: 10.5194/angeo-38-27-2020. da Silva R.P., Denardini C.M., Marques M.S., Resende L.C.A., Moro J., et al. Ionospheric total electron content responses to HILDCAA intervals. Ann. Geophys. 2020, vol. 38, no. 1, pp. 27–34. DOI: 10.5194/angeo-38-27-2020. Deminov M.G., Deminova G.F., Zherebtsov G.A., Polekh N.M. Statistical properties of variability of the quiet ionosphere F2-layer maximum parameters over Irkutsk under low solar activity. Adv. Space Res. 2011, vol. 51, no. 5, pp. 702–711. DOI: 10.1016/j.asr.2012.09.037. Deminov M.G., Deminova G.F., Zherebtsov G.A., Polekh N.M. Statistical properties of variability of the quiet ionosphere F2-layer maximum parameters over Irkutsk under low solar activity. Adv. Space Res. 2011, vol. 51, no. 5, pp. 702–711. DOI: 10.1016/j.asr.2012.09.037. Ercha A., Ridley A.J., Zhang D., Xiao Z. Analyzing the hemispheric asymmetry in the thermospheric density response to geomagnetic storms. J. Geophys. Res. 2012, vol. 117, no. A08317. DOI: 10.1029/2011JA017259. Ercha A., Ridley A.J., Zhang D., Xiao Z. Analyzing the hemispheric asymmetry in the thermospheric density response to geomagnetic storms. J. Geophys. Res. 2012, vol. 117, no. A08317. DOI: 10.1029/2011JA017259. Field P.R., Rishbeth H. The response of the ionospheric F2-layer to geomagnetic activity: an analysis of wordwide data. J. Atmos. Terr. Phys. 1997, vol. 59, no. 2, pp. 163–180. DOI: 10.1016/S1364-6826(96)00085-5. Field P.R., Rishbeth H. The response of the ionospheric F2-layer to geomagnetic activity: an analysis of wordwide data. J. Atmos. Terr. Phys. 1997, vol. 59, no. 2, pp. 163–180. DOI: 10.1016/S1364-6826(96)00085-5. Gonzalez W.D., Joselyn J.A., Kamide Y., Kroehl H.W., Rostoker G., Tsurutani B.T., et al. What is a geomagnetic storm? J. Geophys. Res. 1994, vol. 99, no. A4, pp. 5771–5792. DOI: 10.1029/93JA02867. Gonzalez W.D., Joselyn J.A., Kamide Y., Kroehl H.W., Rostoker G., Tsurutani B.T., et al. What is a geomagnetic storm? J. Geophys. Res. 1994, vol. 99, no. A4, pp. 5771–5792. DOI: 10.1029/93JA02867. Gonzalez W.D., Tsurutani B.T., Clúa de Gonzalez A.L. Interplanetary origin of geomagnetic storms. Space Sci. Rev. 1999, vol. 88, pp. 529–562. DOI: 10.1023/A:1005160129098. Gonzalez W.D., Tsurutani B.T., Clúa de Gonzalez A.L. Interplanetary origin of geomagnetic storms. Space Sci. Rev. 1999, vol. 88, pp. 529–562. DOI: 10.1023/A:1005160129098. Klimenko M.V., Klimenko V.V., Ratovsky K.G., Goncharenko L.P., Sahai Y., Fagundes P.R., et al. Numerical modeling of ionospheric effects in the middle- and low-latitude F region during geomagnetic storm sequence of 9–14 September 2005. Radio Sci. 2011, vol. 46, no. 3, RS0D03. DOI: 10.1029/2010RS004590. Klimenko M.V., Klimenko V.V., Ratovsky K.G., Goncharenko L.P., Sahai Y., Fagundes P.R., et al. Numerical modeling of ionospheric effects in the middle- and low-latitude F region during geomagnetic storm sequence of 9–14 September 2005. Radio Sci. 2011, vol. 46, no. 3, RS0D03. DOI: 10.1029/2010RS004590. Klimenko M.V., Klimenko V.V., Zakharenkova I.E., Ratovsky K.G., Korenkova N.A., Yasyukevich Yu.V., et al. Similarity and differences in morphology and mechanisms of the foF2 and TEC disturbances during the geomagnetic storms on 26–30 September 2011. Ann. Geophys. 2017, vol. 35, no. 4, pp. 923–938. DOI: 10.5194/angeo-35-923-2017. Klimenko M.V., Klimenko V.V., Zakharenkova I.E., Ratovsky K.G., Korenkova N.A., Yasyukevich Yu.V., et al. Similarity and differences in morphology and mechanisms of the foF2 and TEC disturbances during the geomagnetic storms on 26–30 September 2011. Ann. Geophys. 2017, vol. 35, no. 4, pp. 923–938. DOI: 10.5194/angeo-35-923-2017. Klimenko M.V., Klimenko V.V., Sukhodolov T.V., Bessarab F.S., Ratovsky K.G., Rozanov E.V. Role of internal atmospheric variability in the estimation of ionospheric response to solar and magnetospheric proton precipitation in January 2005. Adv. Space Res. 2023, vol. 71, iss. 11, pp. 4576–4586. DOI: 10.1016/j.asr.2023.01.012. Klimenko M.V., Klimenko V.V., Sukhodolov T.V., Bessarab F.S., Ratovsky K.G., Rozanov E.V. Role of internal atmospheric variability in the estimation of ionospheric response to solar and magnetospheric proton precipitation in January 2005. Adv. Space Res. 2023, vol. 71, iss. 11, pp. 4576–4586. DOI: 10.1016/j.asr.2023.01.012. Lei J., Zhu Q., Wang W., Burns A.G., Zhao B., Luan X., Zhong J., Dou X.. Response of the topside and bottomside ionosphere at low and middle latitudes to the October 2003 superstorms. J. Geophys. Res.: Space Phys. 2015, vol. 120, no. 8, pp. 6974–6986. DOI: 10.1002/2015JA021310. Lei J., Zhu Q., Wang W., Burns A.G., Zhao B., Luan X., Zhong J., Dou X.. Response of the topside and bottomside ionosphere at low and middle latitudes to the October 2003 superstorms. J. Geophys. Res.: Space Phys. 2015, vol. 120, no. 8, pp. 6974–6986. DOI: 10.1002/2015JA021310. Liu J., Wang W., Burns A., Yue X., Zhang S., Zhang Y., Huang C. Profiles of ionospheric storm-enhanced density during the 17 March 2015 great storm. J. Geophys. Res.: Space Phys. 2016, vol. 121, no. 1, pp. 727–744. DOI: 10.1002/2015JA021832. Liu J., Wang W., Burns A., Yue X., Zhang S., Zhang Y., Huang C. Profiles of ionospheric storm-enhanced density during the 17 March 2015 great storm. J. Geophys. Res.: Space Phys. 2016, vol. 121, no. 1, pp. 727–744. DOI: 10.1002/2015JA021832. Lu G., Richmond A.D., Roble R.G., Emery B.A. Coexistence of ionospheric positive and negative storm phases under northern winter conditions: A case study J. Geophys. Res. 2001, vol. 106, no. A11, pp. 24493–24504. DOI: 10.1029/2001JA000003. Lu G., Richmond A.D., Roble R.G., Emery B.A. Coexistence of ionospheric positive and negative storm phases under northern winter conditions: A case study J. Geophys. Res. 2001, vol. 106, no. A11, pp. 24493–24504. DOI: 10.1029/2001JA000003. Marques de Souza Franco A., Hajra R., Echer E., Bolzan M.J.A. Seasonal features of geomagnetic activity: a study on the solar activity dependence. Ann. Geophys. 2021, vol. 39, no. 5, pp. 929–943. DOI: 10.5194/angeo-39-929-2021. Marques de Souza Franco A., Hajra R., Echer E., Bolzan M.J.A. Seasonal features of geomagnetic activity: a study on the solar activity dependence. Ann. Geophys. 2021, vol. 39, no. 5, pp. 929–943. DOI: 10.5194/angeo-39-929-2021. Mayr H.G., Harris I., Spencer N.W. Some properties of upper atmosphere dynamics. Rev. Geophys. Space Phys. 1978, vol. 16, pp. 539–565. DOI: 10.1029/RG016i004p00539. Mayr H.G., Harris I., Spencer N.W. Some properties of upper atmosphere dynamics. Rev. Geophys. Space Phys. 1978, vol. 16, pp. 539–565. DOI: 10.1029/RG016i004p00539. Mendillo M. Storms in the ionosphere: Patterns and processes for total electron content. Rev. Geophys. 2006, vol. 44, RG4001. DOI: 10.1029/2005RG000193. Mendillo M. Storms in the ionosphere: Patterns and processes for total electron content. Rev. Geophys. 2006, vol. 44, RG4001. DOI: 10.1029/2005RG000193. Mikhailov A.V. Ionospheric F2-layer storms. Fis. Tierra. 2000, vol. 12, pp. 223–262. Mikhailov A.V. Ionospheric F2-layer storms. Fis. Tierra. 2000, vol. 12, pp. 223–262. Pedatella N.M. Impact of the lower atmosphere on the ionosphere response to a geomagnetic superstorm. Geophys. Res. Lett. 2016, vol. 43, pp. 9383–9389. DOI: 10.1002/2016GL070592. Pedatella N.M. Impact of the lower atmosphere on the ionosphere response to a geomagnetic superstorm. Geophys. Res. Lett. 2016, vol. 43, pp. 9383–9389. DOI: 10.1002/2016GL070592. Pedatella N.M., Liu H.-L. The influence of internal atmospheric variability on the ionosphere response to a geomagnetic storm. Geophys. Res. Lett. 2018, vol. 45, no. 10, pp. 4578–4585. DOI: 10.1029/2018GL077867. Pedatella N.M., Liu H.-L. The influence of internal atmospheric variability on the ionosphere response to a geomagnetic storm. Geophys. Res. Lett. 2018, vol. 45, no. 10, pp. 4578–4585. DOI: 10.1029/2018GL077867. Prölss G.W. Ionospheric F-region storms: unsolved problems. Characterizing the Ionosphere. Meeting Proc. RTO-MP739 IST-056. Paper 10. Neuilly-sur-Seine, France: RTO. 2006, pp. 10-1–10-20. Prölss G.W. Ionospheric F-region storms: unsolved problems. Characterizing the Ionosphere. Meeting Proc. RTO-MP739 IST-056. Paper 10. Neuilly-sur-Seine, France: RTO. 2006, pp. 10-1–10-20. Prölss G.W. Ionospheric storms at mid-latitudes: A short review. Midlatitude Ionospheric Dynamics and Disturbances, AGU Monograph. 2008, vol. 181, pp. 9–24. Prölss G.W. Ionospheric storms at mid-latitudes: A short review. Midlatitude Ionospheric Dynamics and Disturbances, AGU Monograph. 2008, vol. 181, pp. 9–24. Ratovsky K.G., Klimenko M.V., Klimenko V.V., Chirik N.V., Korenkova N.A., Kotova D.S. After-effects of geomagnetic storms: Statistical analysis and theoretical explanation. Solar-Terrestrial Physics. 2018, vol. 4, no. 4, pp. 26–32. DOI: 10.12737/stp-44201804. Ratovsky K.G., Klimenko M.V., Klimenko V.V., Chirik N.V., Korenkova N.A., Kotova D.S. After-effects of geomagnetic storms: Statistical analysis and theoretical explanation. Solar-Terrestrial Physics. 2018, vol. 4, no. 4, pp. 26–32. DOI: 10.12737/stp-44201804. Ratovsky K.G., Klimenko M.V., Yasyukevich Yu.V., Klimenko V.V., Vesnin A.M. Statistical analysis and interpretation of high-, mid- and low-latitude responses in regional electron content to geomagnetic storms. Atmosphere. 2020, vol. 11, no. 12, p. 1308. DOI: 10.3390/atmos11121308. Ratovsky K.G., Klimenko M.V., Yasyukevich Yu.V., Klimenko V.V., Vesnin A.M. Statistical analysis and interpretation of high-, mid- and low-latitude responses in regional electron content to geomagnetic storms. Atmosphere. 2020, vol. 11, no. 12, p. 1308. DOI: 10.3390/atmos11121308. Ratovsky K.G., Klimenko M.V., Vesnin A.M., Belyuchenko K.V., Yasyukevich Yu.V. Comparative analysis of geomagnetic events identified according to different indices. Bull. Russ. Acad. Sci. Phys. 2024, vol. 88, no. 3, pp. 296–302. DOI: 10.1134/S1062873823705433. Ratovsky K.G., Klimenko M.V., Vesnin A.M., Belyuchenko K.V., Yasyukevich Yu.V. Comparative analysis of geomagnetic events identified according to different indices. Bull. Russ. Acad. Sci. Phys. 2024, vol. 88, no. 3, pp. 296–302. DOI: 10.1134/S1062873823705433. Rishbeth H., Mendillo M. Patterns of F2-layer variability. J. Atmos. Solar-Terr. Phys. 2001, vol. 63, pp. 1661–1680. DOI: 10.1016/S1364-6826(01)00036-0. Rishbeth H., Mendillo M. Patterns of F2-layer variability. J. Atmos. Solar-Terr. Phys. 2001, vol. 63, pp. 1661–1680. DOI: 10.1016/S1364-6826(01)00036-0. Rodger A.S., Wrenn G.L., Rishbeth H. Geomagnetic storms in the Antarctic F-region. II. Physical interpretation. J. Atmos. Terr. Phys. 1989, vol. 51, no. 11-12, pp. 851–866. DOI: 10.1016/0021-9169(89)90002-0. Rodger A.S., Wrenn G.L., Rishbeth H. Geomagnetic storms in the Antarctic F-region. II. Physical interpretation. J. Atmos. Terr. Phys. 1989, vol. 51, no. 11-12, pp. 851–866. DOI: 10.1016/0021-9169(89)90002-0. Schaer S., Beutler G., Rothacher M. Mapping and predicting the ionosphere. Proc. IGS AC Workshop. Darmstadt, Germany, 1998, pp. 307–320. Schaer S., Beutler G., Rothacher M. Mapping and predicting the ionosphere. Proc. IGS AC Workshop. Darmstadt, Germany, 1998, pp. 307–320. Titheridge J.E., Buonsanto M.J. A Comparison of Northern and Southern hemisphere TEC storm behavior. J. Atmos. Terr. Phys. 1988, vol. 50, no. 9, pp. 763–780. DOI: 10.1016/0021-9169(88)90100-6. Titheridge J.E., Buonsanto M.J. A Comparison of Northern and Southern hemisphere TEC storm behavior. J. Atmos. Terr. Phys. 1988, vol. 50, no. 9, pp. 763–780. DOI: 10.1016/0021-9169(88)90100-6. Wrenn G.L., Rodger A.S., Rishbeth H. Geomagnetic storms in the Antarctic F-region. I. Diurnal and seasonal patterns for main phase effects. J. Atmos. Terr. Phys. 1987, vol. 49, no. 9, pp. 901–913. DOI: 10.1016/0021-9169(87)90004-3. Wrenn G.L., Rodger A.S., Rishbeth H. Geomagnetic storms in the Antarctic F-region. I. Diurnal and seasonal patterns for main phase effects. J. Atmos. Terr. Phys. 1987, vol. 49, no. 9, pp. 901–913. DOI: 10.1016/0021-9169(87)90004-3. URL: https://omniweb.gsfc.nasa.gov (accessed May 6, 2023). URL: https://omniweb.gsfc.nasa.gov (accessed May 6, 2023). URL: ftp://ftp.unibe.ch/aiub/CODE/ (accessed December 1, 2023). URL: ftp://ftp.unibe.ch/aiub/CODE/ (accessed December 1, 2023). URL: https://simurg.iszf.irk.ru/ (accessed December 1, 2023). URL: https://simurg.iszf.irk.ru/ (accessed December 1, 2023).