OCTAVES : VLF/LF ionosphere observation network

Welcome Contact Station list Acknowledgments Collaboration Data Document Link Award Publication


Low frequency (LF) and very low frequency (VLF) radio waves propagate between earth’s surface and lower edge of ionosphere (70-90km, approx.) at long distance. As modification of the lower ionosphere causes changes in received signal amplitude and phase, LF/VLF radio observation is a useful probe to detect variation of electron density in the lower ionosphere. We have constructed radio observation network from low to high latitudes. Scientific targets of this network are

  • Energetic particle precipitation from radiation belts
  • Lightning effects on upper and middle atmospheres.
  • Solar X-ray flare and proton event effect on upper and middle atmospheres.
  • Effects of solar eclipse, atmospheric gravity waves, and sound wave on the lower ionosphere
  • Detection of gamma ray burst


  • PI: Fuminori Tsuchiya (Tohoku-U) tsuchiya _at_ pparc.gp.tohoku.ac.jp
  • Co-I: Hiroyo Ohya (Chiba-U) ohya _at_ faculty.chiba-u.jp
  • Co-I (database): Manabu Yagi (Kobe-U)

Station list

Code Location Latitude Longitude Antenna Data format
ATH Athabasca/Canada 54.7 246.7 LF4060 Ver2.X(2010-10-24 -)
KAG Kagoshima/Japan 43.45 143.77

LFL1010 (2016-12-20 – 2019-10-27)

DXonePro (2019-10-27 -)

Ver2.X(2016-12-20 -)
KEVO KEVO/Finland 69.70 27.14 loop antenna Ver2.6(2022-09-16 -)
MAM Maimaga/Russia 63.06 129.56


Ver2.X(2017-01-29 -)
NYA Ny-Alseund/Norway 78.933 11.867 LF4060 Ver2.X(2010-03-07 -)
PIN Pinawa/Canada 50.259 264.135 Loop antenna Ver2.X(2019-08-27-)
PKR Pokar Flat/AK USA 65.125 212.512 DXonePro Ver2.X(2014-10-17 -)
PTK Pontianak/Indonesia 00.003 109.367 LF4060 Ver2.X(2010-08-26 -)
RKB Rikubetsu/Japan 43.45 143.77 LF4060 Ver1.0(2006-03-08 – 2010-04-24)
Ver1.1(2010-04-28 – 2015-03-15)
Ver2.X(2015-03-15 -)
SGR Sasaguri/Japan 33.632 130.505 LFL1010 Ver2.X(2014-11-27 -2017-12-26)
SRB Saraburi/Thailand 14.528 100.910 LF4060 (2012-06-12 -) Ver2.X(2012-06-12 -)
DXonePro (2014-03-09 -)
TKN Takine/Japan 37.342 140.676 LFL1010 Ver2.X(2014-12-13 – 2015-03)
TWN Tainann/ROC 23.07 120.12 LF4060 (2007-12-28 -) Ver1.0(2007-12-28 – 2010-04-22)
DXonePro (2013-03-04 -) Ver1.1(2010-04-27 – 2014-11-15)
Ver2.X(2014-12-28 -)
ZAO Zao/Japan 38.10 140.53 DXonePro Ver1.0(2007-10-10 – 2010-02-21)
Ver2.X(2010-02-21 -2014-8-17)
  • Electric monopole : LF4060, DXonePro
  • Orthogonal magnetic loop : LFL1010


  • This project is carried out by the joint research program of the Institute for Space-Earth Environmental Research, Nagoya University.
  • This project is supported by the Inter–university Upper atmosphere Global Observation NETwork (IUGONET) project funded by the Ministry of Education, Culture, Sports, Science and Technology of Japan.
  • This project was supported by JSPS Grants-in-Aid for Scientific Research (20740281).
Code Site name Acknowledgments
ATH Athabasca/Canada Dr. Martin Connors, Athabasca University
KAG Kagoshima/Japan Dr. Shiokawa, Nagoya University
MAM Maimaga/Russia Dr. Dmitry Baishev, IKFIA SB RAS
NYA Ny-Alseund/Norway National Institute of Polar Research, Japan
    The Norwegian Polar Institute
PIN Pinawa/Canada Operated by Canadian Space Agency
PKR Polar Flat/AK USA Dr. Donald Hampton, University of Alaska, Fairbanks
PTK Pontianak/Indonesia Dr. Timbul Manik, LAPAN
RKB Rikubetsu/Japan Drs. Shiokawa and Miyoshi, Nagoya University
    Mr. Yokozeki, Rikubetsu observatory
SGR Sasaguri/Japan Drs. Yoshikawa, Abe, and Uozumi, Kyushu University
SRB Saraburi/Thailand Prof. Thanawat Jarupongsakul and Mr. Vijak Pangsapa, Chulalongkorn University
    Dr. Boossarasiri Thana , Promotion of Teaching Science and Technology (IPST)
TKN Takine/Japan Mr. Ohno, Hoshi-no-mura astronomical observatory
TWN Tainann/ROC Dr. Alfred Chen, NCKU
ZAO Zao/Japan Zao observatory, Tohoku University





Name Award Title of paper

Asuka Hirai
(Tohoku U)

150th SGEPSS Fall meeting (Nov 2021)
SGEPSS Student Good Presentation (Div-3)

The mechanism of frequency increase of IPDP type EMIC waves: event analysis of ground and satellite observations
Hiroki Nomoto

150th SGEPSS Fall meeting (Nov 2021)
SGEPSS Student Good Presentation (Div-3)

Modeling of Perturbation in the Lower Ionosphere caused by EMIC waves using Numerical Simulation of subionospheric VLF signals
Asuka Hirai
(Tohoku U)
Japan Geoscience Union 2021 (May 2021)
Japan Geoscience Union Meeting 2021 – Student Presentation Award
Properties of EMIC waves observed by Van Allen Probes and ground-based magnetometers during relativistic electron precipitation
 Tekkan Akashi
(Chiba U)

 Society of Atmospheric Electricity of Japan 99th Conference (Jan, 2021)
Student Presentation Awards

Takuya Miyashita
(Chiba U)
URSI-JRSM 2019 (Sept, 2019)
Student Paper Competition, Third Prize
ULF Modulation of Energetic Electron Precipitations Observed by VLF/LF Standard Radio Waves

Asuka Hirai
(Tohoku U)

15th AOGS Annual meeting (Jun 2018)
AOGS Best Student Poster Award (ST19-A010)
Temporal and Spatial Correspondence of Pc1/EMIC Waves and Energetic Electron Precipitation with Ground-Based Observation on 27 March, 2017

Related publication

  • Yuma Nozaki, Hiroyo Ohya, Fuminori Tsuchiya, Kenro Nozaki, Hiroyuki Nakata, and Kazuo Shiokawa (2022). Local Time and Seasonal Variations in the D-Region Ionosphere: Does It
    Reflect Sudden Stratospheric Warming Effects?. Special Section on URSI-JRSM2022, Radio Science Letters (volume 4). DOI:10.46620/22-0045
  • Kentaro Tanaka, Hiroyo Ohya, Fuminori Tsuchiya, Kenro Nozaki, Mariko Teramoto, Kazuo Shiokawa, Yoshizumi Miyoshi, Martin Connors, and Hiroyuki Nakata (2022). Ultra Low Frequency Modulation of Energetic Electron Precipitation in the D-Region Ionosphere in a Magnetically Quiet Time Using OCTAVE Very Low Frequency and Low Frequency (VLF/LF) Observations. Special Section on URSI-JRSM2022, Radio Science Letters (volume 4). DOI:10.46620/22-0049
  • Masaharu Nakayama, Hiroyo Ohya, Fuminori Tsuchiya, Kenro Nozaki, Kazuo Shiokawa, and Hiroyuki Nakata (2022). Horizontal Inhomogeneity in the D-Region Ionosphere During an X-Class
    Solar Flare Determined by OCTAVE VLF Observations. Special Section on URSI-JRSM2022, Radio Science Letters (volume 4). DOI:10.46620/22-0050
  • Akashi, T., H. Ohya, F. Tsuchiya, K. Nozaki, H. Nakata (2021). Variation in the D-region ionosphere after the 2015 Nepal earthquake using LF transmitter signals. Journal of Atmospheric Electricity, 40 (1), 1-9. https://doi.org/10.1541/jae.40.1
  • Kawamura, M., T. Sakanoi, M. Fukizawa, Y. Miyoshi, K. Hosokawa, F. Tsuchiya, Y. Katoh, Y. Ogawa, K. Asamura, S. Saito, H. Spence, A. Johnson, S. Oyama, U. Brändström (2021). Simultaneous Pulsating Aurora and Microburst Observations With Ground‐Based Fast Auroral Imagers and CubeSat FIREBIRD‐II. Geophysical Research Letters, 48(18). https://doi.org/10.1029/2021gl094494
  • Miyoshi, Y., S. Saito S. Kurita K. Asamura K. Hosokawa T. Sakanoi T. Mitani Y. Ogawa S. Oyama F. Tsuchiya S. L. Jones A. N. Jaynes J. B. Blake (2020). Relativistic electron microbursts as high energy tail of pulsating aurora electrons. Geophysical Research Letters, 47, e2020GL090360. https://doi.org/10.1029/2020GL090360
  • Miyashita, T., H. Ohya, F. Tsuchiya, A. Hirai, M. Ozaki, K. Shiokawa, Y. Miyoshi, N. Nishitani, M. Teramoto, M. Connors, S. G. Shepherd, Y. Kasahara, A. Kumamoto, M. Shoji, I. Shinohara, H. Nakata, T. Takano (2020),  ULF Modulation of Energetic Electron Precipitations Observed by VLF/LF Radio Propagation,  Radio Science Bulletin, Vol. 372, http://www.ursi.org/content/RSB/RSB_372_2020_03.pdf 
  • Hirai, A., F. Tsuchiya, T. Obara, Y. Kasaba, Y. Katoh, H. Misawa, K. Shiokawa, Y. Miyoshi, S. Kurita, S. Matsuda, M. Connors, T. Nagatsuma, K. Sakaguchi, Y. Kasahara, A. Kumamoto, A. Matsuoka, M. Shoji, I. Shinohara and J. M. Albert (2018), Temporal and Spatial Correspondence of Pc1/EMIC Waves and Relativistic Electron Precipitations Observed with Ground-Based Multi-Instruments on 27 March 2017, Geophysical Research Letters, https://doi.org/10.1029/2018GL080126
  • Tsuchiya, F., A. Hirai, T. Obara, H. Misawa, S. Kurita, Y. Miyoshi, K. Shiokawa, M. Connors, M. Ozaki, Y. Kasahara, A. Kumamoto, Y. Kasaba, A. Matsuoka, M. Shoji, I. Shinohara (2018), Energetic electron precipitation associated with pulsating aurora observed by VLF radio propagation during recovery phase of substorm on 27 March 2017, Geophysical Research Letters, https://doi.org/10.1029/2018GL080222
  • Ohya H., F. Tsuchiya, Y. Takishita, H. Shinagawa, K. Nozaki, K. Shiokawa(2018), Periodic Oscillations in the D Region Ionosphere After the 2011 Tohoku Earthquake Using LF Standard Radio Waves, Journal of Geophysical Research-Space physics 123(6) 5261-5270, https://doi.org/10.1029/2018JA025289
  • Shiokawa K, et al. (2017), Ground-based instruments of the PWING project to investigate dynamics of the inner magnetosphere at subauroral latitudes as a part of the ERG-ground coordinated observation network, Earth, Planets and Space201769:160, https://doi.org/10.1186/s40623-017-0745-9
  • Miyoshi, Y., S. Oyama, S. Saito, S. Kurita, H. Fujiwara, R. Kataoka, Y. Ebihara, C. Kletzing,G. Reeves, O. Santolik, M. Clilverd, C. J. Rodger, E. Turunen, and F. Tsuchiya (2015), Energetic electron precipitation associated with pulsating aurora: EISCAT and Van Allen Probe observations, Journal of Geophysical Research,120 2754-2766, https://doi.org/10.1002/2014JA020690
  • Shiokawa, K., Y. Yokoyama, A. Ieda, Y. Miyoshi, R. Nomura, S. Lee, N. Sunagawa, Y. Miyashita, M. Ozaki, K. Ishizaka, S. Yagitani, R. Kataoka, F. Tsuchiya, I. Schofield and M. Connors, Ground-based ELF/VLF chorus observations at subauroral latitudes—VLF-CHAIN Campaign, Journal of Geophysical Research 9 7363-7379, https://doi.org/10.1002/2014JA020161
  • Ohya, H., F. Tsuchiya, H. Nakata, K. Shiokawa, Y. Miyoshi, K. Yamashita, and Y. Takahashi (2012), Reflection height of daytime tweek atmospherics during the solar eclipse of 22 July 2009, J. Geophys Res. 117 A11310, https://doi.org/10.1029/2012JA018151
  • Tadokoro, H., F. Tsuchiya, Y. Miyoshi, Y. Katoh, A. Morioka, and H. Misawa (2009), Storm-time electron flux precipitation in the inner radiation belt cause by wave-particle interactions, Ann. Geophys 27 1669-1677, Ann. Geophys., 27, 1669-1677, https://doi.org/10.5194/angeo-27-1669-2009
  • Tadokoro, H., F. Tsuchiya, Y. Miyoshi, H. Misawa, A. Morioka, and D. S. Evans (2007), Electron flux enhancement in the inner radiation belt during moderate magnetic storms, Annales geophysicae 25(6) 1359-1364, https://doi.org/10.5194/angeo-25-1359-2007