Annual variations in westward auroral electrojet and substorm occurrence rate during solar cycle 23

Jianpeng Guo, T. I. Pulkkinen, E. I. Tanskanen, Xueshang Feng, Barbara A. Emery, Huixin Liu, Chaoxu Liu, Dingkun Zhong

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

The International Monitor for Auroral Geomagnetic Effects network magnetic measurements during the period 1995-2009 are used to characterize the annual variations in the westward electrojet. The results suggest that the annual variations in different local time sectors are quite different due to the different sources. In the MLT sector 2200-0100, the annual variations with maxima in winter suggest they are caused by the combined effects of the convective electric field and the conductivity associated with particle precipitation. Furthermore, the conductivity seems to play a more important role in the MLT sector ∼2200-2320, while the convective electric field appears to be more important in the MLT sector ∼2320-0100. In the MLT sector 0300-0600, the annual variations with maxima in summer suggest they are caused by solar EUV conductivity effect and the equinoctial effect. The solar EUV conductivity effect works by increasing ionospheric conductivity and enhancing the westward electrojet in summer, while the equinoctial effect works by decreasing solar wind-magnetosphere coupling efficiency and weakening the westward electrojet in winter. In the MLT sector 0100-0300, the annual variations are relatively weak and can be attributed to the combined effects of annual variations caused by all the previously mentioned effects. In addition, we find that a significant annual variation in substorm occurrence rate, mainly occurring in the premidnight region, is quite similar to that in the westward electrojet. We suggest that elevated solar wind driving during the winter months contributes to higher substorm occurrence in winter in the Northern Hemisphere. Key Points Annual variations of WEJ in 2200-0100 MLT are associated with solar wind driving Annual variations of WEJ in 0300-0600 MLT are due to EUV and equinoctial effect Solar wind driving contributes to higher substorm occurrence in winter

Original languageEnglish
Pages (from-to)2061-2068
Number of pages8
JournalJournal of Geophysical Research: Space Physics
Volume119
Issue number3
DOIs
Publication statusPublished - Jan 1 2014

Fingerprint

auroral electrojets
Solar wind
electrojet
annual variations
solar cycles
solar cycle
annual variation
occurrences
electrojets
winter
sectors
conductivity
electric field
solar wind
Electric fields
Magnetosphere
Magnetic variables measurement
summer
wind variations
ionospheric conductivity

All Science Journal Classification (ASJC) codes

  • Geophysics
  • Forestry
  • Oceanography
  • Aquatic Science
  • Ecology
  • Water Science and Technology
  • Soil Science
  • Geochemistry and Petrology
  • Earth-Surface Processes
  • Atmospheric Science
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science
  • Palaeontology

Cite this

Annual variations in westward auroral electrojet and substorm occurrence rate during solar cycle 23. / Guo, Jianpeng; Pulkkinen, T. I.; Tanskanen, E. I.; Feng, Xueshang; Emery, Barbara A.; Liu, Huixin; Liu, Chaoxu; Zhong, Dingkun.

In: Journal of Geophysical Research: Space Physics, Vol. 119, No. 3, 01.01.2014, p. 2061-2068.

Research output: Contribution to journalArticle

Guo, Jianpeng ; Pulkkinen, T. I. ; Tanskanen, E. I. ; Feng, Xueshang ; Emery, Barbara A. ; Liu, Huixin ; Liu, Chaoxu ; Zhong, Dingkun. / Annual variations in westward auroral electrojet and substorm occurrence rate during solar cycle 23. In: Journal of Geophysical Research: Space Physics. 2014 ; Vol. 119, No. 3. pp. 2061-2068.
@article{462c34abfc62404f92eafbf9e3707fc8,
title = "Annual variations in westward auroral electrojet and substorm occurrence rate during solar cycle 23",
abstract = "The International Monitor for Auroral Geomagnetic Effects network magnetic measurements during the period 1995-2009 are used to characterize the annual variations in the westward electrojet. The results suggest that the annual variations in different local time sectors are quite different due to the different sources. In the MLT sector 2200-0100, the annual variations with maxima in winter suggest they are caused by the combined effects of the convective electric field and the conductivity associated with particle precipitation. Furthermore, the conductivity seems to play a more important role in the MLT sector ∼2200-2320, while the convective electric field appears to be more important in the MLT sector ∼2320-0100. In the MLT sector 0300-0600, the annual variations with maxima in summer suggest they are caused by solar EUV conductivity effect and the equinoctial effect. The solar EUV conductivity effect works by increasing ionospheric conductivity and enhancing the westward electrojet in summer, while the equinoctial effect works by decreasing solar wind-magnetosphere coupling efficiency and weakening the westward electrojet in winter. In the MLT sector 0100-0300, the annual variations are relatively weak and can be attributed to the combined effects of annual variations caused by all the previously mentioned effects. In addition, we find that a significant annual variation in substorm occurrence rate, mainly occurring in the premidnight region, is quite similar to that in the westward electrojet. We suggest that elevated solar wind driving during the winter months contributes to higher substorm occurrence in winter in the Northern Hemisphere. Key Points Annual variations of WEJ in 2200-0100 MLT are associated with solar wind driving Annual variations of WEJ in 0300-0600 MLT are due to EUV and equinoctial effect Solar wind driving contributes to higher substorm occurrence in winter",
author = "Jianpeng Guo and Pulkkinen, {T. I.} and Tanskanen, {E. I.} and Xueshang Feng and Emery, {Barbara A.} and Huixin Liu and Chaoxu Liu and Dingkun Zhong",
year = "2014",
month = "1",
day = "1",
doi = "10.1002/2013JA019742",
language = "English",
volume = "119",
pages = "2061--2068",
journal = "Journal of Geophysical Research",
issn = "0148-0227",
number = "3",

}

TY - JOUR

T1 - Annual variations in westward auroral electrojet and substorm occurrence rate during solar cycle 23

AU - Guo, Jianpeng

AU - Pulkkinen, T. I.

AU - Tanskanen, E. I.

AU - Feng, Xueshang

AU - Emery, Barbara A.

AU - Liu, Huixin

AU - Liu, Chaoxu

AU - Zhong, Dingkun

PY - 2014/1/1

Y1 - 2014/1/1

N2 - The International Monitor for Auroral Geomagnetic Effects network magnetic measurements during the period 1995-2009 are used to characterize the annual variations in the westward electrojet. The results suggest that the annual variations in different local time sectors are quite different due to the different sources. In the MLT sector 2200-0100, the annual variations with maxima in winter suggest they are caused by the combined effects of the convective electric field and the conductivity associated with particle precipitation. Furthermore, the conductivity seems to play a more important role in the MLT sector ∼2200-2320, while the convective electric field appears to be more important in the MLT sector ∼2320-0100. In the MLT sector 0300-0600, the annual variations with maxima in summer suggest they are caused by solar EUV conductivity effect and the equinoctial effect. The solar EUV conductivity effect works by increasing ionospheric conductivity and enhancing the westward electrojet in summer, while the equinoctial effect works by decreasing solar wind-magnetosphere coupling efficiency and weakening the westward electrojet in winter. In the MLT sector 0100-0300, the annual variations are relatively weak and can be attributed to the combined effects of annual variations caused by all the previously mentioned effects. In addition, we find that a significant annual variation in substorm occurrence rate, mainly occurring in the premidnight region, is quite similar to that in the westward electrojet. We suggest that elevated solar wind driving during the winter months contributes to higher substorm occurrence in winter in the Northern Hemisphere. Key Points Annual variations of WEJ in 2200-0100 MLT are associated with solar wind driving Annual variations of WEJ in 0300-0600 MLT are due to EUV and equinoctial effect Solar wind driving contributes to higher substorm occurrence in winter

AB - The International Monitor for Auroral Geomagnetic Effects network magnetic measurements during the period 1995-2009 are used to characterize the annual variations in the westward electrojet. The results suggest that the annual variations in different local time sectors are quite different due to the different sources. In the MLT sector 2200-0100, the annual variations with maxima in winter suggest they are caused by the combined effects of the convective electric field and the conductivity associated with particle precipitation. Furthermore, the conductivity seems to play a more important role in the MLT sector ∼2200-2320, while the convective electric field appears to be more important in the MLT sector ∼2320-0100. In the MLT sector 0300-0600, the annual variations with maxima in summer suggest they are caused by solar EUV conductivity effect and the equinoctial effect. The solar EUV conductivity effect works by increasing ionospheric conductivity and enhancing the westward electrojet in summer, while the equinoctial effect works by decreasing solar wind-magnetosphere coupling efficiency and weakening the westward electrojet in winter. In the MLT sector 0100-0300, the annual variations are relatively weak and can be attributed to the combined effects of annual variations caused by all the previously mentioned effects. In addition, we find that a significant annual variation in substorm occurrence rate, mainly occurring in the premidnight region, is quite similar to that in the westward electrojet. We suggest that elevated solar wind driving during the winter months contributes to higher substorm occurrence in winter in the Northern Hemisphere. Key Points Annual variations of WEJ in 2200-0100 MLT are associated with solar wind driving Annual variations of WEJ in 0300-0600 MLT are due to EUV and equinoctial effect Solar wind driving contributes to higher substorm occurrence in winter

UR - http://www.scopus.com/inward/record.url?scp=84899064069&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84899064069&partnerID=8YFLogxK

U2 - 10.1002/2013JA019742

DO - 10.1002/2013JA019742

M3 - Article

AN - SCOPUS:84899064069

VL - 119

SP - 2061

EP - 2068

JO - Journal of Geophysical Research

JF - Journal of Geophysical Research

SN - 0148-0227

IS - 3

ER -