Journal cover Journal topic
Annales Geophysicae An interactive open-access journal of the European Geosciences Union
Journal topic

Journal metrics

Journal metrics

  • IF value: 1.585 IF 1.585
  • IF 5-year value: 1.698 IF 5-year
    1.698
  • CiteScore value: 1.62 CiteScore
    1.62
  • SNIP value: 0.820 SNIP 0.820
  • IPP value: 1.52 IPP 1.52
  • SJR value: 0.781 SJR 0.781
  • Scimago H <br class='hide-on-tablet hide-on-mobile'>index value: 83 Scimago H
    index 83
  • h5-index value: 24 h5-index 24
Volume 25, issue 11
Ann. Geophys., 25, 2393–2403, 2007
https://doi.org/10.5194/angeo-25-2393-2007
© Author(s) 2007. This work is distributed under
the Creative Commons Attribution 3.0 License.
Ann. Geophys., 25, 2393–2403, 2007
https://doi.org/10.5194/angeo-25-2393-2007
© Author(s) 2007. This work is distributed under
the Creative Commons Attribution 3.0 License.

  29 Nov 2007

29 Nov 2007

Electromagnetic energy deposition rate in the polar upper thermosphere derived from the EISCAT Svalbard radar and CUTLASS Finland radar observations

H. Fujiwara1, R. Kataoka2, M. Suzuki1, S. Maeda3, S. Nozawa4, K. Hosokawa5, H. Fukunishi1, N. Sato6, and M. Lester7 H. Fujiwara et al.
  • 1Department of Geophysics, Graduate School of Science, Tohoku University, Sendai, Japan
  • 2RIKEN (The Institute of Physics and Chemical Research), Saitama, Japan
  • 3Faculty for the Study of Contemporary Society, Kyoto Women's University, Kyoto, Japan
  • 4Solar-Terrestrial Environment Laboratory, Nagoya University, Nagoya, Japan
  • 5The University of Electro-Communications, Tokyo, Japan
  • 6National Institute of Polar Research, Tokyo, Japan
  • 7Department of Physics and Astronomy, University of Leicester, Leicester, UK

Abstract. From simultaneous observations of the European incoherent scatter Svalbard radar (ESR) and the Cooperative UK Twin Located Auroral Sounding System (CUTLASS) Finland radar on 9 March 1999, we have derived the height distributions of the thermospheric heating rate at the F region height in association with electromagnetic energy inputs into the dayside polar cap/cusp region. The ESR and CUTLASS radar observations provide the ionospheric parameters with fine time-resolutions of a few minutes. Although the geomagnetic activity was rather moderate (Kp=3+~4), the electric field obtained from the ESR data sometimes shows values exceeding 40 mV/m. The estimated passive energy deposition rates are also larger than 150 W/kg in the upper thermosphere over the ESR site during the period of the enhanced electric field. In addition, enhancements of the Pedersen conductivity also contribute to heating the upper thermosphere, while there is only a small contribution for thermospheric heating from the direct particle heating due to soft particle precipitation in the dayside polar cap/cusp region. In the same period, the CUTLASS observations of the ion drift show the signature of poleward moving pulsed ionospheric flows with a recurrence rate of about 10–20 min. The estimated electromagnetic energy deposition rate shows the existence of the strong heat source in the dayside polar cap/cusp region of the upper thermosphere in association with the dayside magnetospheric phenomena of reconnections and flux transfer events.

Publications Copernicus
Download
Citation