Preprints
https://doi.org/10.5194/angeo-2021-27
https://doi.org/10.5194/angeo-2021-27

  24 Jun 2021

24 Jun 2021

Review status: this preprint is currently under review for the journal ANGEO.

Seasonal features of geomagnetic activity: evidence for solar activity dependence?

Adriane Marques de Souza Franco1, Rajkumar Hajra2, Ezequiel Echer1, and Mauricio José Alves Bolzan3 Adriane Marques de Souza Franco et al.
  • 1Instituto Nacional de Pesquisas Espaciais (INPE), São José dos Campos, Brazil
  • 2Indian Institute of Technology Indore, Simrol, Indore 453552, India
  • 3Federal University of Jatai, Jatai, Brazil

Abstract. Seasonal features of geomagnetic activity and their solar wind-interplanetary drivers are studied using more than 5 solar cycles of geomagnetic activity and solar wind observations. This study involves a total of 1239 geomagnetic storms of varying intensity identified using the Dst index from January 1963 to December 2019, a total of 75863 substorms identified from the SML index from January 1976 to December 2019, a total of 145 high-intensity long-duration continuous auroral electrojet (AE) activity (HILDCAA) events identified using the AE index from January 1975 to December 2017. The occurrence rates of the substorms, geomagnetic storms, including moderate (−50 nT ≥ Dst > −100 nT) and intense (−100 nT ≥ Dst > −250 nT), exhibit a significant semi-annual variation (periodicity ~ 6 months), while the super storms (Dst ≤ −250 nT) and HILDCAAs do not exhibit any clear seasonal feature. The geomagnetic activity indices Dst and ap exhibit a semi-annual variation while AE exhibits an annual variation (periodicity ~ 1 year). The annual and semi-annual variations are found to be driven by the annual variation of the solar wind speed Vsw and the semi-annual variation of the coupling function V Bs (where V = Vsw, and Bs is the southward component of the interplanetary magnetic field), respectively. We present a detailed analysis of the annual and semi-annual variations and their dependencies on the solar activity cycles separated as the odd, even, weak and strong solar cycles.

Adriane Marques de Souza Franco et al.

Status: open (until 13 Aug 2021)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • CC1: 'Comment on angeo-2021-27', Paul PUKITE, 26 Jun 2021 reply
  • RC1: 'Comment on angeo-2021-27', Anonymous Referee #1, 04 Jul 2021 reply

Adriane Marques de Souza Franco et al.

Adriane Marques de Souza Franco et al.

Viewed

Total article views: 343 (including HTML, PDF, and XML)
HTML PDF XML Total BibTeX EndNote
281 55 7 343 3 2
  • HTML: 281
  • PDF: 55
  • XML: 7
  • Total: 343
  • BibTeX: 3
  • EndNote: 2
Views and downloads (calculated since 24 Jun 2021)
Cumulative views and downloads (calculated since 24 Jun 2021)

Viewed (geographical distribution)

Total article views: 319 (including HTML, PDF, and XML) Thereof 319 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 
Latest update: 24 Jul 2021
Download
Short summary
We used an up-to-date list of substorms, HILDCAAs and geomagnetic storms of varying intensity along with all availablegeomagnetic indices during the space exploration era to explore the seasonal features of the geomagnetic activity and their drivers. As substorms, HILDCAAs and magnetic storms of varying intensity have varying solar/interplanetary drivers, such astudy is important for a complete understanding of the seasonal features of the geomagnetic response to the solar/interplanetary events.