University of Oulu

Kozlovsky, A., Shalimov, S., Lester, M., & Belova, E. (2021). Polar mesosphere summer echoes and possible signatures of pulsating aurora detected by the meteor radar. Journal of Geophysical Research: Space Physics, 126, e2020JA028855.

Polar mesosphere summer echoes and possible signatures of pulsating aurora detected by the meteor radar

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Author: Kozlovsky, A.1; Shalimov, S.2,3; Lester, M.4;
Organizations: 1Sodankylä Geophysical Observatory of the University of Oulu, Sodankylä, Finland
2Institute of Physics of the Earth, Moscow, Russia
3Space Research Institute, Moscow, Russia
4Department of Physics and Astronomy, University of Leicester, Leicester, UK
5Swedish Institute of Space Physics, Kiruna, Sweden
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 4 MB)
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Language: English
Published: American Geophysical Union, 2021
Publish Date: 2022-04-20


Using data of the all-sky interferometric meteor radar (SKiYMET, 36.9 MHz) operating in the Sodankylä Geophysical Observatory (67°22′N, 26°38′E, Finland) we found a specific type of polar mesosphere summer echo (PMSE), the power of which exhibits irregular variations at a frequency of the order of a few Hz. We classified such radar echoes as pulsating PMSE. These echoes were observed in late June-July in the morning sector (4–12 MLT) during geomagnetic storms. They were received from a narrow range of altitudes near 82 km, which corresponds to the altitude of noctilucent clouds where ice particles of about 50-nm radii exist. During pulsating PMSE, the SGO ionosonde showed an electron density of the order of 3 × 10¹¹ m⁻³ around 82 km, and enhanced D-region ionization was manifested in the cosmic noise absorption. We suggest that the power of PMSE is modulated by bursts of electron precipitation corresponding to the few-Hz internal modulation of pulsating aurora. During a short precipitation burst of 50–100 keV electrons, additional electrons can attach to the ice particles due to the presence of hyperthermal electrons according to the hypothesis proposed by Rosenberg et al. (2012, This leads to an increase of the power of PMSE. After the burst is ended, the ice particles are deionized with a characteristic time of about 0.2 s due to attractive interaction with ions.

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Series: Journal of geophysical research. Space physics
ISSN: 2169-9380
ISSN-E: 2169-9402
ISSN-L: 2169-9380
Volume: 126
Issue: 11
Article number: e2020JA028855
DOI: 10.1029/2020JA028855
Type of Publication: A1 Journal article – refereed
Field of Science: 115 Astronomy and space science
Funding: S. Shalimov acknowledges support from the Academy of Finland via Grant 322360. M. Lester acknowledges support by STFC Grant ST/S000429/1.
Academy of Finland Grant Number: 322360
Detailed Information: 322360 (Academy of Finland Funding decision)
Dataset Reference: The meteor radar data were collected at SGO ( Data used in the paper are available online (at The SGO ionosonde and CNA data are available at The OMNI data were obtained from the GSFC/SPDF OMNIWeb interface at The ESRAD data are available at
Copyright information: © 2021. American Geophysical Union.