HF radar observations of high-aspect angle backscatter from the E-region
International audience We present evidence for the observation of high-aspect angle HF radar backscatter from the auroral electrojets, and describe the spectral characteristics of these echoes. Such backscatter is observed at very near ranges where ionospheric refraction is not sufficient to bring t...
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ftccsdartic:oai:HAL:hal-00329300v1 2023-11-12T04:19:18+01:00 HF radar observations of high-aspect angle backscatter from the E-region Milan, S. E. Lester, M. Yeoman, T. K. Robinson, T. R. Uspensky, M. V. Villain, J.-P. Department of Physics and Astronomy Leicester University of Leicester Finnish Meteorological Institute (FMI) Centre National de la Recherche Scientifique (CNRS) 2004-03-19 https://hal.science/hal-00329300 https://hal.science/hal-00329300/document https://hal.science/hal-00329300/file/angeo-22-829-2004.pdf en eng HAL CCSD European Geosciences Union hal-00329300 https://hal.science/hal-00329300 https://hal.science/hal-00329300/document https://hal.science/hal-00329300/file/angeo-22-829-2004.pdf info:eu-repo/semantics/OpenAccess ISSN: 0992-7689 EISSN: 1432-0576 Annales Geophysicae https://hal.science/hal-00329300 Annales Geophysicae, 2004, 22 (3), pp.829-847 [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU]Sciences of the Universe [physics]/Earth Sciences info:eu-repo/semantics/article Journal articles 2004 ftccsdartic 2023-10-21T23:03:18Z International audience We present evidence for the observation of high-aspect angle HF radar backscatter from the auroral electrojets, and describe the spectral characteristics of these echoes. Such backscatter is observed at very near ranges where ionospheric refraction is not sufficient to bring the sounding radio waves to orthogonality with the magnetic field; the frequency dependence of this propagation effect is investigated with the Stereo upgrade of the CUTLASS Iceland radar. We term the occurrence of such echoes the "high-aspect angle irregularity region" or HAIR. It is suggested that backscatter is observed at aspect angles as high as 30°, with an aspect sensitivity as low as 1dB deg –1 . These echoes are distinguished from normal electrojet backscatter by having low Doppler shifts with an azimuthal dependence that appears more consistent with the direction of the convection electric field than with the expected electron drift direction. This is discussed in terms of the linear theory dispersion relation for electrojet waves. Key words. Ionosphere (ionospheric irregularities; plasma waves and instabilities; auroral ionosphere) Article in Journal/Newspaper Iceland Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) |
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Open Polar |
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Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) |
op_collection_id |
ftccsdartic |
language |
English |
topic |
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU]Sciences of the Universe [physics]/Earth Sciences |
spellingShingle |
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU]Sciences of the Universe [physics]/Earth Sciences Milan, S. E. Lester, M. Yeoman, T. K. Robinson, T. R. Uspensky, M. V. Villain, J.-P. HF radar observations of high-aspect angle backscatter from the E-region |
topic_facet |
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU]Sciences of the Universe [physics]/Earth Sciences |
description |
International audience We present evidence for the observation of high-aspect angle HF radar backscatter from the auroral electrojets, and describe the spectral characteristics of these echoes. Such backscatter is observed at very near ranges where ionospheric refraction is not sufficient to bring the sounding radio waves to orthogonality with the magnetic field; the frequency dependence of this propagation effect is investigated with the Stereo upgrade of the CUTLASS Iceland radar. We term the occurrence of such echoes the "high-aspect angle irregularity region" or HAIR. It is suggested that backscatter is observed at aspect angles as high as 30°, with an aspect sensitivity as low as 1dB deg –1 . These echoes are distinguished from normal electrojet backscatter by having low Doppler shifts with an azimuthal dependence that appears more consistent with the direction of the convection electric field than with the expected electron drift direction. This is discussed in terms of the linear theory dispersion relation for electrojet waves. Key words. Ionosphere (ionospheric irregularities; plasma waves and instabilities; auroral ionosphere) |
author2 |
Department of Physics and Astronomy Leicester University of Leicester Finnish Meteorological Institute (FMI) Centre National de la Recherche Scientifique (CNRS) |
format |
Article in Journal/Newspaper |
author |
Milan, S. E. Lester, M. Yeoman, T. K. Robinson, T. R. Uspensky, M. V. Villain, J.-P. |
author_facet |
Milan, S. E. Lester, M. Yeoman, T. K. Robinson, T. R. Uspensky, M. V. Villain, J.-P. |
author_sort |
Milan, S. E. |
title |
HF radar observations of high-aspect angle backscatter from the E-region |
title_short |
HF radar observations of high-aspect angle backscatter from the E-region |
title_full |
HF radar observations of high-aspect angle backscatter from the E-region |
title_fullStr |
HF radar observations of high-aspect angle backscatter from the E-region |
title_full_unstemmed |
HF radar observations of high-aspect angle backscatter from the E-region |
title_sort |
hf radar observations of high-aspect angle backscatter from the e-region |
publisher |
HAL CCSD |
publishDate |
2004 |
url |
https://hal.science/hal-00329300 https://hal.science/hal-00329300/document https://hal.science/hal-00329300/file/angeo-22-829-2004.pdf |
genre |
Iceland |
genre_facet |
Iceland |
op_source |
ISSN: 0992-7689 EISSN: 1432-0576 Annales Geophysicae https://hal.science/hal-00329300 Annales Geophysicae, 2004, 22 (3), pp.829-847 |
op_relation |
hal-00329300 https://hal.science/hal-00329300 https://hal.science/hal-00329300/document https://hal.science/hal-00329300/file/angeo-22-829-2004.pdf |
op_rights |
info:eu-repo/semantics/OpenAccess |
_version_ |
1782335783702626304 |