Articles | Volume 40, issue 4
https://doi.org/10.5194/angeo-40-475-2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/angeo-40-475-2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Regular paper
| 
12 Jul 2022
Regular paper |
| 12 Jul 2022
| 12 Jul 2022
Reconstruction of precipitating electrons and three-dimensional structure of a pulsating auroral patch from monochromatic auroral images obtained from multiple observation points
Mizuki Fukizawa
CORRESPONDING AUTHOR
National Institute of Polar Research, Tachikawa 190-8518, Japan
Takeshi Sakanoi
Graduate School of Science, Tohoku University, Sendai 980-8578,
Japan
Yoshimasa Tanaka
National Institute of Polar Research, Tachikawa 190-8518, Japan
Polar Environment Data Science Center, Joint Support-Center for Data
Science Research, Research Organization of Information and Systems,
Tachikawa 190-0014, Japan
Department of Polar Science, The Graduate University for Advanced
Studies (SOKENDAI), Tachikawa 190-8518, Japan
Yasunobu Ogawa
National Institute of Polar Research, Tachikawa 190-8518, Japan
Polar Environment Data Science Center, Joint Support-Center for Data
Science Research, Research Organization of Information and Systems,
Tachikawa 190-0014, Japan
Department of Polar Science, The Graduate University for Advanced
Studies (SOKENDAI), Tachikawa 190-8518, Japan
Keisuke Hosokawa
Graduate School of Informatics and Engineering, University of
Electro-Communications, Chofu 182-8585, Japan
Björn Gustavsson
Department of Physics and Technology, Arctic University of Norway (UiT), 9037
Tromsø, Norway
Kirsti Kauristie
Space Research and Observation Technologies, Finnish Meteorological Institute, 00101 Helsinki, Finland
Alexander Kozlovsky
Sodankylä Geophysical Observatory, University of Oulu, 90014 Oulu, Finland
Tero Raita
Sodankylä Geophysical Observatory, University of Oulu, 90014 Oulu, Finland
Urban Brändström
Solar Terrestrial Atmosphere Research Program (STAR), Swedish Institute of Space Physics (IRF), 981 28 Kiruna, Sweden
Tima Sergienko
Solar Terrestrial Atmosphere Research Program (STAR), Swedish Institute of Space Physics (IRF), 981 28 Kiruna, Sweden
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Gunter Stober, Alan Liu, Alexander Kozlovsky, Zishun Qiao, Witali Krochin, Guochun Shi, Johan Kero, Masaki Tsutsumi, Njål Gulbrandsen, Satonori Nozawa, Mark Lester, Kathrin Baumgarten, Evgenia Belova, and Nicholas Mitchell
Ann. Geophys., 41, 197–208, https://doi.org/10.5194/angeo-41-197-2023, https://doi.org/10.5194/angeo-41-197-2023, 2023
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The Hunga Tonga–Hunga Ha‘apai volcanic eruption was one of the most vigorous volcanic explosions in the last centuries. The eruption launched many atmospheric waves traveling around the Earth. In this study, we identify these volcanic waves at the edge of space in the mesosphere/lower-thermosphere, leveraging wind observations conducted with multi-static meteor radars in northern Europe and with the Chilean Observation Network De Meteor Radars (CONDOR).
Johann Stamm, Juha Vierinen, Björn Gustavsson, and Andres Spicher
Ann. Geophys., 41, 55–67, https://doi.org/10.5194/angeo-41-55-2023, https://doi.org/10.5194/angeo-41-55-2023, 2023
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The study of some ionospheric events benefit from the knowledge of how the physics varies over a volume and over time. Examples are studies of aurora or energy deposition. With EISCAT3D, measurements of ion velocity vectors in a volume will be possible for the first time. We present a technique that uses a set of such measurements to estimate electric field and neutral wind. The technique relies on adding restrictions to the estimates. We successfully consider restrictions based on physics.
Daniel K. Whiter, Noora Partamies, Björn Gustavsson, and Kirsti Kauristie
Ann. Geophys., 41, 1–12, https://doi.org/10.5194/angeo-41-1-2023, https://doi.org/10.5194/angeo-41-1-2023, 2023
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Gunter Stober, Alan Liu, Alexander Kozlovsky, Zishun Qiao, Ales Kuchar, Christoph Jacobi, Chris Meek, Diego Janches, Guiping Liu, Masaki Tsutsumi, Njål Gulbrandsen, Satonori Nozawa, Mark Lester, Evgenia Belova, Johan Kero, and Nicholas Mitchell
Atmos. Meas. Tech., 15, 5769–5792, https://doi.org/10.5194/amt-15-5769-2022, https://doi.org/10.5194/amt-15-5769-2022, 2022
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Noora Partamies, Daniel Whiter, Kirsti Kauristie, and Stefano Massetti
Ann. Geophys., 40, 605–618, https://doi.org/10.5194/angeo-40-605-2022, https://doi.org/10.5194/angeo-40-605-2022, 2022
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Sebastian Käki, Ari Viljanen, Liisa Juusola, and Kirsti Kauristie
Ann. Geophys., 40, 107–119, https://doi.org/10.5194/angeo-40-107-2022, https://doi.org/10.5194/angeo-40-107-2022, 2022
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During auroral substorms, the ionospheric electric currents change rapidly, and a large amount of energy is dissipated. We combine ionospheric current data derived from the Swarm satellite mission with the substorm database from the SuperMAG ground magnetometer network. We obtain statistics of the strength and location of the currents relative to the substorm onset. Our results show that low-earth orbit satellites give a coherent picture of the main features in the substorm current system.
Fasil Tesema, Noora Partamies, Daniel K. Whiter, and Yasunobu Ogawa
Ann. Geophys., 40, 1–10, https://doi.org/10.5194/angeo-40-1-2022, https://doi.org/10.5194/angeo-40-1-2022, 2022
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In this study, we present the comparison between an auroral model and EISCAT radar electron densities during pulsating aurorae. We test whether an overpassing satellite measurement of the average energy spectrum is a reasonable estimate for pulsating aurora electron precipitation. When patchy pulsating aurora is dominant in the morning sector, the overpass-averaged spectrum is found to be a reasonable estimate – but not when there is a mix of pulsating aurora types in the post-midnight sector.
Johann Stamm, Juha Vierinen, and Björn Gustavsson
Ann. Geophys., 39, 961–974, https://doi.org/10.5194/angeo-39-961-2021, https://doi.org/10.5194/angeo-39-961-2021, 2021
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Measurements of the electric field and neutral wind in the ionosphere are important for understanding energy flows or electric currents. With incoherent scatter radars (ISRs), we can measure the velocity of the ions, which depends on both the electrical field and the neutral wind. In this paper, we investigate methods to use ISR data to find reasonable values for both parameters. We find that electric field can be well measured down to 125 km height and neutral wind below this height.
Gunter Stober, Alexander Kozlovsky, Alan Liu, Zishun Qiao, Masaki Tsutsumi, Chris Hall, Satonori Nozawa, Mark Lester, Evgenia Belova, Johan Kero, Patrick J. Espy, Robert E. Hibbins, and Nicholas Mitchell
Atmos. Meas. Tech., 14, 6509–6532, https://doi.org/10.5194/amt-14-6509-2021, https://doi.org/10.5194/amt-14-6509-2021, 2021
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Wind observations at the edge to space, 70–110 km altitude, are challenging. Meteor radars have become a widely used instrument to obtain mean wind profiles above an instrument for these heights. We describe an advanced mathematical concept and present a tomographic analysis using several meteor radars located in Finland, Sweden and Norway, as well as Chile, to derive the three-dimensional flow field. We show an example of a gravity wave decelerating the mean flow.
Gunter Stober, Ales Kuchar, Dimitry Pokhotelov, Huixin Liu, Han-Li Liu, Hauke Schmidt, Christoph Jacobi, Kathrin Baumgarten, Peter Brown, Diego Janches, Damian Murphy, Alexander Kozlovsky, Mark Lester, Evgenia Belova, Johan Kero, and Nicholas Mitchell
Atmos. Chem. Phys., 21, 13855–13902, https://doi.org/10.5194/acp-21-13855-2021, https://doi.org/10.5194/acp-21-13855-2021, 2021
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Little is known about the climate change of wind systems in the mesosphere and lower thermosphere at the edge of space at altitudes from 70–110 km. Meteor radars represent a well-accepted remote sensing technique to measure winds at these altitudes. Here we present a state-of-the-art climatological interhemispheric comparison using continuous and long-lasting observations from worldwide distributed meteor radars from the Arctic to the Antarctic and sophisticated general circulation models.
Nadezda Yagova, Alexander Kozlovsky, Evgeny Fedorov, and Olga Kozyreva
Ann. Geophys., 39, 549–562, https://doi.org/10.5194/angeo-39-549-2021, https://doi.org/10.5194/angeo-39-549-2021, 2021
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We present a study of ultralow-frequency waves in the ionosphere and on the ground. These waves are very slow (their periods are about several minutes). They are registered on the ground as geomagnetic pulsations. No simple dependence exists between geomagnetic and ionospheric pulsations. Here we study not only selected pulsations with very high amplitudes but also usual pulsations and try to answer the question, which pulsation parameters are favorable for modulation of the ionosphere?
Emranul Sarkar, Alexander Kozlovsky, Thomas Ulich, Ilkka Virtanen, Mark Lester, and Bernd Kaifler
Atmos. Meas. Tech., 14, 4157–4169, https://doi.org/10.5194/amt-14-4157-2021, https://doi.org/10.5194/amt-14-4157-2021, 2021
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The biasing effect in meteor radar temperature has been a pressing issue for the last 2 decades. This paper has addressed the underlying reasons for such a biasing effect on both theoretical and experimental grounds. An improved statistical method has been developed which allows atmospheric temperatures at around 90 km to be measured with meteor radar in an independent way such that any subsequent bias correction or calibration is no longer required.
Daniel Kastinen, Johan Kero, Alexander Kozlovsky, and Mark Lester
Atmos. Meas. Tech., 14, 3583–3596, https://doi.org/10.5194/amt-14-3583-2021, https://doi.org/10.5194/amt-14-3583-2021, 2021
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When a meteor enters the atmosphere, it causes a trail of diffusing plasma that moves with the neutral wind. An interferometric radar system can measure such trails and determine its location. However, there is a chance of determining the wrong position due to noise. We simulate this behaviour and use the simulations to successfully determine the true location of ambiguous events. We also successfully test two simple temporal integration methods for avoiding such erroneous determinations.
Torbjørn Tveito, Juha Vierinen, Björn Gustavsson, and Viswanathan Lakshmi Narayanan
Ann. Geophys., 39, 427–438, https://doi.org/10.5194/angeo-39-427-2021, https://doi.org/10.5194/angeo-39-427-2021, 2021
Short summary
Short summary
This work explores the role of EISCAT 3D as a tool for planetary mapping. Due to the challenges inherent in detecting the signals reflected from faraway bodies, we have concluded that only the Moon is a viable mapping target. We estimate the impact of the ionosphere on lunar mapping, concluding that its distorting effects should be easily manageable. EISCAT 3D will be useful for mapping the lunar nearside due to its previously unused frequency (233 MHz) and its interferometric capabilities.
Johann Stamm, Juha Vierinen, Juan M. Urco, Björn Gustavsson, and Jorge L. Chau
Ann. Geophys., 39, 119–134, https://doi.org/10.5194/angeo-39-119-2021, https://doi.org/10.5194/angeo-39-119-2021, 2021
Cited articles
Aso, T., Hashimoto, T., Abe, M., Ono, T., and Ejiri, M.: On the analysis of
aurora stereo observations, J. Geomagn. Geoelectr., 42, 579–595,
https://doi.org/10.5636/jgg.42.579, 1990.
Aso, T., Ejiri, M., Miyaoka, H., Hashimoto, T., Abu, T. Y., and Abe, M.:
Aurora stereo observation in Iceland, Proc. NIPR Symp. Up. Atmos. Phys., 6,
1–14, 1993.
Aso, T., Ejiri, M., Urashima, A., Miyaoka, H., Steen, Å.,
Brändstrom, U., and Gustavsson, B.: First results of auroral tomography
from ALIS-Japan multi-station observations in March, 1995, Earth Planet.
Space, 50, 81–86, https://doi.org/10.1186/BF03352088, 1998.
Brown, N. B., Davis, T. N., Hallinan, T. J., and Stenbaek-Nielsen, H. C.:
Altitude of pulsating aurora determined by a new instrumental thechnique,
Geophys. Res. Lett., 3, 403–404, https://doi.org/10.1029/GL003i007p00403, 1976.
Davis, T. N.: Observed characteristics of auroral forms, Space Sci. Rev., 22, 77–113, https://doi.org/10.1007/BF00215814, 1978.
Frey, S., Frey, H. U., Carr, D. J., Bauer, O. H., and Haerendel, G.: Auroral
emission profiles extracted from three-dimensionally reconstructed arcs, J.
Geophys. Res.-Space, 101, 21731–21741, https://doi.org/10.1029/96ja01899,
1996.
Fujii, R., Oguti, T., and Yamamoto, T.: Relationships between pulsating auroras and field-aligned electric currents, Mem. Natl. Inst. Polar Res. Spec. Issue, 36, 95–1003, 1985.
Fukizawa, M.: Movie A1, Logo TIB AV-Portal
[video], https://doi.org/10.5446/57558, 2022.
Gillies, D. M., Knudsen, D., Spanswick, E., Donovan, E., Burchill, J., and Patrick, M.: Swarm observations of field-aligned currents associated with pulsating auroral patches, J. Geophys. Res. A, 120, 9484–9499, https://doi.org/10.1002/2015JA021416, 2015.
Hosokawa, K. and Ogawa, Y.: Pedersen current carried by electrons in auroral D-region, Geophys. Res. Lett., 37, 1–5, https://doi.org/10.1029/2010GL044746, 2010.
Jones, A. V.: Aurora, D. Reidel Publishing Company, Dordrecht, Springer, ISBN 978-94-010-2099-2, 1974.
Jones, S. L., Lessard, M. R., Fernandes, P. A., Lummerzheim, D., Semeter, J.
L., Heinselman, C. J., Lynch, K. A., Michell, R. G., Kintner, P. M.,
Stenbaek-Nielsen, H. C., and Asamura, K.: PFISR and ROPA observations of
pulsating aurora, J. Atmos. Sol.-Terr. Phys., 71, 708–716,
https://doi.org/10.1016/j.jastp.2008.10.004, 2009.
Kataoka, R., Fukuda, Y., Uchida, H. A., Yamada, H., Miyoshi, Y., Ebihara,
Y., Dahlgren, H., and Hampton, D.: High-speed stereoscopy of aurora, Ann.
Geophys., 34, 41–44, https://doi.org/10.5194/angeo-34-41-2016, 2016.
Kennel, C. F. and Petschek, H. E.: Limit on stably trapped particle fluxes,
J. Geophys. Res., 71, 1–28, https://doi.org/10.1029/JZ071i001p00001, 1966.
McEwen, D. J., Yee, E., Whalen, B. A., and Yau, A. W.: Electron energy
measurements in pulsating auroras, Can. J. Phys., 59, 1106–1115,
https://doi.org/10.1139/p81-146, 1981.
Miyoshi, Y., Saito, S., Seki, K., Nishiyama, T., Kataoka, R., Asamura, K.,
Katoh, Y., Ebihara, Y., Sakanoi, T., Hirahara, M., Oyama, S., Kurita, S., and
Santolik, O.: Relation between energy spectra of pulsating aurora electrons
and frequency spectra of whistler-mode chorus waves, J. Geophys. Res.-Space, 120, 7728–7736, https://doi.org/10.1002/2015JA021562, 2015.
Nygrén, T., Markkanen, M., Lehtinen, M., and Kaila, K.: Application of
stochastic inversion in auroral tomography, Ann. Geophys., 14,
1124–1133, https://doi.org/10.1007/s00585-996-1124-1, 1997.
Ogawa, Y.: Watec observation database in NIPR [data set], http://pc115.seg20.nipr.ac.jp/www/optical/watec/skb/awi/rawdata/, last access: 6 June 2022a.
Ogawa, Y.: EISCAT database in NIPR, EISCAT [data set], http://pc115.seg20.nipr.ac.jp/www/eiscatdata/, last access: 27 February, 2022b.
Ogawa, Y., Tanaka, Y., Kadokura, A., Hosokawa, K., Ebihara, Y., Motoba, T.,
Gustavsson, B., Brändström, U., Sato, Y., Oyama, S., Ozaki, M.,
Raita, T., Sigernes, F., Nozawa, S., Shiokawa, K., Kosch, M., Kauristie, K.,
Hall, C., Suzuki, S., Miyoshi, Y., Gerrard, A., Miyaoka, H., and Fujii, R.:
Development of low-cost multi-wavelength imager system for studies of aurora
and airglow, Polar Sci., 23, 100501, https://doi.org/10.1016/j.polar.2019.100501, 2020a.
Ogawa, Y., Kadokura, A., and Ejiri, M. K.: Optical calibration system of NIPR
for aurora and airglow observations, Polar Sci., 26, 100570,
https://doi.org/10.1016/j.polar.2020.100570, 2020b.
Picone, J. M., Hedin, A. E., Drob, D. P., and Aikin, A. C.: NRLMSISE-00
empirical model of the atmosphere: Statistical comparisons and scientific
issues, J. Geophys. Res.-Space, 107, 1468,
https://doi.org/10.1029/2002JA009430, 2002.
Raita, T. and Kauristie, K.: Subset of the MIRACLE emCCD all-sky camera data at 427.8 nm from ABK and KIL on 18 Feb 2018 00–02 UT, Etsin [data set], https://doi.org/10.23729/e86df44b-8dad-44e5-89f3-4bea0d3d1236, 2022.
Sangalli, L., Partamies, N., Syrjäsuo, M., Enell, C. F., Kauristie, K.,
and Mäkinen, S.: Performance study of the new EMCCD-based all-sky
cameras for auroral imaging, Int. J. Remote Sens., 32, 2987–3003,
https://doi.org/10.1080/01431161.2010.541505, 2011.
Sato, N., Wright, D. M., Carlson, C. W., Ebihara, Y., Sato, M., Saemundsson,
T., Milan, S. E., and Lester, M.: Generation region of pulsating aurora
obtained simultaneously by the FAST satellite and a Syowa-Iceland conjugate
pair of observatories, J. Geophys. Res.-Space, 109, 1–15,
https://doi.org/10.1029/2004JA010419, 2004.
Semeter, J. and Kamalabadi, F.: Determination of primary electron spectra
from incoherent scatter radar measurements of the auroral e region, Radio
Sci., 40, RS2006, https://doi.org/10.1029/2004RS003042, 2005.
Sergienko, T. and Ivanov, V.: A new approach to calculate the excitation of
atmospheric gases by auroral electron impact, Ann. Geophys. Eur. Geophys.
Soc., 11, 717–727, 1993.
Shepherd, G. G. and Fälthammar, C.-G.: Implications of extreme thinness
of pulsating auroral structures, J. Geophys. Res.-Space, 85,
217–218, https://doi.org/10.1029/ja085ia01p00217, 1980.
Stenbaek-Nielsen, H. C. and Hallinan, T. J.: Pulsating auroras: Evidence for
noncollisional thermalization of precipitating electrons, J. Geophys. Res.,
84, 3257–3271, https://doi.org/10.1029/JA084iA07p03257, 1979.
Stone, M.: Cross-validatory choice and assessment of statistical predictions
(with discussion), J. R. Stat. Soc. Ser. B, 38, 102–102,
https://doi.org/10.1111/j.2517-6161.1976.tb01573.x, 1974.
Tanaka, Y. M., Aso, T., Gustavsson, B., Tanabe, K., Ogawa, Y., Kadokura, A.,
Miyaoka, H., Sergienko, T., Brändström, U., and Sandahl, I.:
Feasibility study on Generalized-Aurora Computed Tomography, Ann. Geophys.,
29, 551–562, https://doi.org/10.5194/angeo-29-551-2011, 2011.
Vickrey, J. F., Vondrak, R. R., and Matthews, S. J.: Energy deposition by
precipitating particles and Joule dissipation in the auroral ionosphere, J.
Geophys. Res.-Space, 87, 5184–5196, https://doi.org/10.1029/ja087ia07p05184,
1982.
Walls, F. L. and Dunn, G. H.: Measurement of total cross sections for
electron recombination with NO+ and O
Yamamoto, T.: On the temporal fluctuations of pulsating auroral luminosity,
J. Geophys. Res., 93, 897–911, https://doi.org/10.1029/JA093iA02p00897, 1988.
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Short summary
The pulsating auroral generation mechanism has been investigated by observing precipitating electrons using rockets or satellites. However, it is difficult for such observations to distinguish temporal changes from spatial ones. In this study, we reconstructed the horizontal 2-D distribution of precipitating electrons using only auroral images. The 3-D aurora structure was also reconstructed. We found that there were both spatial and temporal changes in the precipitating electron energy.
The pulsating auroral generation mechanism has been investigated by observing precipitating...
