Log in

Comparing the diurnal variations in the SuperMAG auroral electrojet indices SML and SMU

  • Article
  • Geophysics
  • Published:
Chinese Science Bulletin

Abstract

Diurnal variations of the SuperMAG auroral electrojet indices (SML and SMU) were examined for the period of 1980–2010, and the differences between SML and SMU were especially analyzed. The diurnal variation of SML with a maximum at around 1100 UT has a prenoon-postnoon asymmetry. At solstices, the diurnal variation of SML is much stronger than that at equinoxes. For the SMU, two maxima are recorded in the diurnal variation with the bigger one at 1700 UT and the smaller one at 0400 UT. The seasonal variations are not obvious in the UT variation characteristics of SMU although the intensity of SMU is changed remarkably season by season. For both SML and SMU, the contributing stations are located at higher geomagnetic latitude around 1600 UT and at lower geomagnetic latitude around 0400 UT. These results indicate that: (1) the SML is mostly controlled by the convection electric field. Its diurnal variation is mainly correlated with the equinoctial and R-M hypothesis; (2) the SMU is largely controlled by the ionospheric conductance. Its diurnal variation is tightly correlated with the solar radiation.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Subscribe and save

Springer+ Basic
EUR 32.99 /Month
  • Get 10 units per month
  • Download Article/Chapter or Ebook
  • 1 Unit = 1 Article or 1 Chapter
  • Cancel anytime
Subscribe now

Buy Now

Price includes VAT (Germany)

Instant access to the full article PDF.

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5

Similar content being viewed by others

References

  1. Davis TN, Sugiura M (1966) Auroral electrojet activity index AE and its universal time variations. J Geophys Res 71:785–801

    Article  Google Scholar 

  2. Vassiliadis D, Klimas AJ, Baker DN et al (1995) A description of the solar wind-magnetosphere coupling based on nonlinear filters. J Geophys Res 100:3495–3512

    Article  Google Scholar 

  3. Kamide Y, Baumjohann W, Daglis IA et al (1998) Current understanding of magnetic storms: storm-substorm relationships. J Geophys Res 103:17705–17728

    Article  Google Scholar 

  4. Xu WY (2009) Variations of the auroral electrojet belt during substorms. Chin J Geophys 52:607–615 (in Chinese)

    Google Scholar 

  5. Zhou XY, Sun W, Ridley AJ et al (2011) Joule heating associated with auroral electrojets during magnetospheric substorms. J Geophys Res 116:A00I28

    Google Scholar 

  6. Du AM, Tsurutani BT, Sun W (2011) Solar wind energy input during prolonged, intense northward interplanetary magnetic fields: a new coupling function. J Geophys Res 116:A12215

    Article  Google Scholar 

  7. Feldstein YI, Grafe A, Gromova LI et al (1997) Auroral electrojets during geomagnetic storms. J Geophys Res 102:14223–14235

    Article  Google Scholar 

  8. Chen GX, Du AM, Xu WY et al (2001) Response of the high-latitude geomagnetic field to the geomagnetic storm of July 15–16, 2000. Sci China Ser A Math 31:111–119 (in Chinese)

    Google Scholar 

  9. Singh AK, Sinha AK, Rawat R et al (2012) A broad climatology of very high latitude substorms. Adv Space Res 50:1512–1523

    Article  Google Scholar 

  10. Akasofu SI (1977) Physics of Magnetospheric substorms. D Reidel Publishing Company, Dordrecht-Boston, pp 381–472

    Book  Google Scholar 

  11. Kamide Y, Akasofu SI (1983) Notes on the auroral electrojet indices. Rev Geophys Space Phys 21:1647–1656

    Article  Google Scholar 

  12. Xu WY, Chen GX (2004) Quantitative analysis of the relationship between polar ionospheric currents and the electrojet indices. Sci China Ser D Earth Sci 34:291–297 (in Chinese)

    Google Scholar 

  13. Ahn BH, Chen GX, Sun W et al (2005) Equatorward expansion of the westward electrojet during magnetically disturbed periods. J Geophys Res 110:A01305

    Google Scholar 

  14. Wang QJ, Du AM, Zhao XD et al (2009) Manifestation of the AE index in substorms on August 6, 1998. Chin J Geophys 52:2943–2950 (in Chinese)

    Google Scholar 

  15. Cortie AL (1912) Sunspots and terrestrial magnetic phenomena, 1898–1911: the cause of the annual variation in magnetic disturbances. MNRAS 73:52

    Article  Google Scholar 

  16. McIntosh DH (1959) On the annual variation of magnetic disturbance. Phil Trans R Soc Lond A 251:525–552

    Article  Google Scholar 

  17. Russell CT, McPherron RL (1973) Semiannual variation of geomagnetic activity. J Geophys Res 78:92–108

    Article  Google Scholar 

  18. Berthelier A (1976) Influence of the polarity of the interplanetary magnetic field on the annual and diurnal variations of magnetic activity. J Geophys Res 81:4546–4552

    Article  Google Scholar 

  19. Hajkowicz LA (1998) Longitudinal (UT) effect in the onset of auroral disturbances over two solar cycles as deduced from the AE-index. Ann Geophys 16:1573–1579

    Article  Google Scholar 

  20. Takalo J, Mursula K (2001) A model for the diurnal universal time variation of the Dst index. J Geophys Res 106:10905–10914

    Article  Google Scholar 

  21. Chen HF (2004) Analysis of the diurnal and semiannual variations of Dst index at different activity levels. J Geophys Res 109:A03212

    Google Scholar 

  22. Cliver EW, Kamide Y, Ling AG (2000) Mountains versus valleys: semiannual variation of geomagnetic activity. J Geophys Res 105:2413–2424

    Article  Google Scholar 

  23. Cliver EW, Kamide Y, Ling AG et al (2001) Semiannual variation of the geomagnetic Dst index: evidence for a dominant nonstorm component. J Geophys Res 106:21297–21304

    Article  Google Scholar 

  24. Cliver EW, Kamide Y, Ling AG (2002) The semiannual variation of geomagnetic activity: phase and profiles for 130 years of aa data. J Atmos Sol Terr Phys 64:47–53

    Article  Google Scholar 

  25. Zhao H, Zong QG (2012) Seasonal and diurnal variation of geomagnetic activity: Russell–McPherron effect during IMF polarity and/or extreme solar wind conditions. J Geophys Res 117:A11222

    Article  Google Scholar 

  26. Kamide Y, Kroehl HW (1994) Auroral electrojet activity during isolated substorms at different local times: a statistical study. Geophys Res Lett 21:389–392

    Article  Google Scholar 

  27. Chen GX, Xu WY, Wei ZG et al (2003) Auroral electrojet oval. Earth Planets Space 55:255–261

    Article  Google Scholar 

  28. Xu WY, Chen GX, Du AM et al (2008) Key points model for polar region currents. J Geophys Res 113:A03S11

    Google Scholar 

  29. Kamide Y, Kokubun S (1996) Two-component auroral electrojet: importance for substorm studies. J Geophys Res 101:13027–13046

    Article  Google Scholar 

  30. Ahn BH, Kroehl HW, Kamide Y et al (2000) Universal time variations of the auroral electrojet indices. J Geophys Res 105:267–275

    Article  Google Scholar 

  31. Ahn BH, Moon GH, Sun W et al (2002) Universal time variation of the Dst index and the relationship between the cumulative AL and Dst indices during geomagnetic storms. J Geophys Res 107:1409

    Article  Google Scholar 

  32. Ahn BH, Moon GH (2003) Seasonal and universal time variations of the AU, AL and Dst indices. J Korean Astron Soc 36:S93–S99

    Article  Google Scholar 

  33. Lyatsky W, Newell PT, Hamza A (2001) Solar illumination as cause of the equinoctial preference for geomagnetic activity. Geophys Res Lett 28:2352–2356

    Article  Google Scholar 

  34. Newell PT, Sotirelis T, Skura JP et al (2002) Ultraviolet insolation drives seasonal and diurnal space weather variations. J Geophys Res 107:1305

    Article  Google Scholar 

  35. Gjerloev JW, Hoffman RA, Ohtani S et al (2010) Response of the auroral electrojet indices to abrupt southward IMF turnings. Ann Geophys 28:1167–1182

    Article  Google Scholar 

  36. Newell PT, Gjerloev JW (2011) Evaluation of SuperMAG auroral electrojet indices as indicators of substorms and auroral power. J Geophys Res 116:A12211

    Article  Google Scholar 

  37. Newell PT, Gjerloev JW (2011) Substorm and magnetosphere characteristic scales inferred from the SuperMAG auroral electrojet indices. J Geophys Res 116:A12232

    Article  Google Scholar 

  38. Wan BD, Li M, Wang Y et al (2013) A preliminary analysis of the center latitude distribution of auroral electrojet. Prog Geophys 28:1655–1661 (in Chinese)

  39. Gjerloev JW (2012) The SuperMAG data processing technique. J Geophys Res 117:A09213

    Google Scholar 

  40. Ohtani S, Ueno G, Higuchi T et al (2005) Annual and semiannual variations of the location and intensity of large-scale field-aligned currents. J Geophys Res 110:A01216

    Google Scholar 

  41. Du AM, Tsurutani BT, Sun W (2008) Anomalous geomagnetic storm of 21–22 January 2005: a storm main phase during northward IMFs. J Geophys Res 113:A10214

    Article  Google Scholar 

  42. Sun W, Zhou XY, Du A (2008) Quantitative separation of the directly-driven and unloading components of the ionospheric electric field. Geophys Res Lett 35:L13104

    Article  Google Scholar 

  43. Mursula K, Hiltula T, Zieger B (2002) Latitudinal gradients of solar wind speed around the ecliptic: systematic displacement of the streamer belt. Geophys Res Lett 29:1738

    Article  Google Scholar 

  44. Boller BR, Stolov HL (1970) Kelvin-Helmholtz instability and the semiannual variation of geomagnetic activity. J Geophys Res 75:6073–6084

    Article  Google Scholar 

  45. Newell PT, Meng CI, Lyons KM (1996) Discrete aurorae are suppressed in sunlight. Nature 381:766–767

    Article  Google Scholar 

Download references

Acknowledgments

This work was supported by the National Basic Research Program of China (2014CB845903, 2011CB811404), the National Natural Science Foundation of China (41104110), the Ocean Public Welfare Scientific Research Project, State Oceanic Administration, China (201005017), and the Program of Chinese Academy of Sciences (ZDYZ2012-1).

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Aimin Du.

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Wang, Y., Du, A., Chen, G. et al. Comparing the diurnal variations in the SuperMAG auroral electrojet indices SML and SMU . Chin. Sci. Bull. 59, 3877–3883 (2014). https://doi.org/10.1007/s11434-014-0451-y

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s11434-014-0451-y

Keywords

Navigation