Mesoscale structure of a morning sector ionospheric shear flow region determined by conjugate Cluster II and MIRACLE ground-based observations
International audience We analyse a conjunction event of the Cluster II spacecraft with the MIRACLE ground-based instrument net-work in northern Fennoscandia on 6 February 2001, between 23:00 and 00:00 UT. Shortly after the spacecraft were located at perigee, the Cluster II satellites' magnetic...
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Other Authors: | , , , , , , , , , , , , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
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HAL CCSD
2003
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Online Access: | https://hal.science/hal-00329276 https://hal.science/hal-00329276/document https://hal.science/hal-00329276/file/angeo-21-1737-2003.pdf |
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ftinsu:oai:HAL:hal-00329276v1 |
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openpolar |
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Open Polar |
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Institut national des sciences de l'Univers: HAL-INSU |
op_collection_id |
ftinsu |
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 Amm, O. Aikio, A. Bosqued, J.-M. Dunlop, M. Fazakerley, A. Janhunen, P. Kauristie, K. Lester, M. Sillanpää, I. Taylor, M. G. G. T. Vontrat-Reberac, A. Mursula, K. André, M. Mesoscale structure of a morning sector ionospheric shear flow region determined by conjugate Cluster II and MIRACLE ground-based observations |
topic_facet |
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU]Sciences of the Universe [physics]/Earth Sciences |
description |
International audience We analyse a conjunction event of the Cluster II spacecraft with the MIRACLE ground-based instrument net-work in northern Fennoscandia on 6 February 2001, between 23:00 and 00:00 UT. Shortly after the spacecraft were located at perigee, the Cluster II satellites' magnetic footpoints move northwards over Scandinavia and Svalbard, almost perfectly aligned with the central chain of the IMAGE magnetometer network, and cross a morning sector ionospheric shear zone during this passage. In this study we focus on the mesoscale structure of the ionosphere. Ionospheric conductances, true horizontal currents, and field-aligned currents (FAC) are calculated from the ground-based measurements of the IMAGE magnetometers and the STARE coherent scatter radar, using the 1-D method of characteristics. An excellent agreement between these results and the FAC observed by Cluster II is reached after averaging the Cluster measurements to mesoscales, as well as between the location of the convection reversal boundary (CRB), as observed by STARE and by the Cluster II EFW instrument. A sheet of downward FAC is observed in the vicinity of the CRB, which is mainly caused by the positive divergence of the electric field there. This FAC sheet is detached by 0.5°–2° of latitude from a more equatorward downward FAC sheet at the poleward flank of the westward electrojet. This latter FAC sheet, as well as the upward FAC at the equatorward flank of the jet, are mainly caused by meridional gradients in the ionospheric conductances, which reach up to 25 S in the electrojet region, but only ~ 5 S poleward of it, with a minimum at the CRB. Particle measurements show that the major part of the downward FAC is carried by upward flowing electrons, and only a small part by downward flowing ions. The open-closed field line boundary is found to be located 3°–4° poleward of the CRB, implying significant errors if the latter is used as a proxy of the former. |
author2 |
Finnish Meteorological Institute (FMI) University of Oulu Centre d'étude spatiale des rayonnements (CESR) Université Toulouse III - Paul Sabatier (UT3) Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP) Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3) Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Centre National de la Recherche Scientifique (CNRS) Space and Atmospheric Physics Group London Blackett Laboratory Imperial College London-Imperial College London Mullard Space Science Laboratory (MSSL) University College of London London (UCL) Radio and Space Plasma Physics Group Leicester (RSPP) University of Leicester Centre d'étude des environnements terrestre et planétaires (CETP) Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS) Swedish Institute of Space Physics Uppsala (IRF) |
format |
Article in Journal/Newspaper |
author |
Amm, O. Aikio, A. Bosqued, J.-M. Dunlop, M. Fazakerley, A. Janhunen, P. Kauristie, K. Lester, M. Sillanpää, I. Taylor, M. G. G. T. Vontrat-Reberac, A. Mursula, K. André, M. |
author_facet |
Amm, O. Aikio, A. Bosqued, J.-M. Dunlop, M. Fazakerley, A. Janhunen, P. Kauristie, K. Lester, M. Sillanpää, I. Taylor, M. G. G. T. Vontrat-Reberac, A. Mursula, K. André, M. |
author_sort |
Amm, O. |
title |
Mesoscale structure of a morning sector ionospheric shear flow region determined by conjugate Cluster II and MIRACLE ground-based observations |
title_short |
Mesoscale structure of a morning sector ionospheric shear flow region determined by conjugate Cluster II and MIRACLE ground-based observations |
title_full |
Mesoscale structure of a morning sector ionospheric shear flow region determined by conjugate Cluster II and MIRACLE ground-based observations |
title_fullStr |
Mesoscale structure of a morning sector ionospheric shear flow region determined by conjugate Cluster II and MIRACLE ground-based observations |
title_full_unstemmed |
Mesoscale structure of a morning sector ionospheric shear flow region determined by conjugate Cluster II and MIRACLE ground-based observations |
title_sort |
mesoscale structure of a morning sector ionospheric shear flow region determined by conjugate cluster ii and miracle ground-based observations |
publisher |
HAL CCSD |
publishDate |
2003 |
url |
https://hal.science/hal-00329276 https://hal.science/hal-00329276/document https://hal.science/hal-00329276/file/angeo-21-1737-2003.pdf |
geographic |
Svalbard |
geographic_facet |
Svalbard |
genre |
Fennoscandia Svalbard |
genre_facet |
Fennoscandia Svalbard |
op_source |
ISSN: 0992-7689 EISSN: 1432-0576 Annales Geophysicae https://hal.science/hal-00329276 Annales Geophysicae, 2003, 21 (8), pp.1737-1751 |
op_relation |
hal-00329276 https://hal.science/hal-00329276 https://hal.science/hal-00329276/document https://hal.science/hal-00329276/file/angeo-21-1737-2003.pdf |
op_rights |
info:eu-repo/semantics/OpenAccess |
_version_ |
1785582993270636544 |
spelling |
ftinsu:oai:HAL:hal-00329276v1 2023-12-17T10:30:05+01:00 Mesoscale structure of a morning sector ionospheric shear flow region determined by conjugate Cluster II and MIRACLE ground-based observations Amm, O. Aikio, A. Bosqued, J.-M. Dunlop, M. Fazakerley, A. Janhunen, P. Kauristie, K. Lester, M. Sillanpää, I. Taylor, M. G. G. T. Vontrat-Reberac, A. Mursula, K. André, M. Finnish Meteorological Institute (FMI) University of Oulu Centre d'étude spatiale des rayonnements (CESR) Université Toulouse III - Paul Sabatier (UT3) Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP) Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3) Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Centre National de la Recherche Scientifique (CNRS) Space and Atmospheric Physics Group London Blackett Laboratory Imperial College London-Imperial College London Mullard Space Science Laboratory (MSSL) University College of London London (UCL) Radio and Space Plasma Physics Group Leicester (RSPP) University of Leicester Centre d'étude des environnements terrestre et planétaires (CETP) Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS) Swedish Institute of Space Physics Uppsala (IRF) 2003 https://hal.science/hal-00329276 https://hal.science/hal-00329276/document https://hal.science/hal-00329276/file/angeo-21-1737-2003.pdf en eng HAL CCSD European Geosciences Union hal-00329276 https://hal.science/hal-00329276 https://hal.science/hal-00329276/document https://hal.science/hal-00329276/file/angeo-21-1737-2003.pdf info:eu-repo/semantics/OpenAccess ISSN: 0992-7689 EISSN: 1432-0576 Annales Geophysicae https://hal.science/hal-00329276 Annales Geophysicae, 2003, 21 (8), pp.1737-1751 [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 2003 ftinsu 2023-11-22T17:35:50Z International audience We analyse a conjunction event of the Cluster II spacecraft with the MIRACLE ground-based instrument net-work in northern Fennoscandia on 6 February 2001, between 23:00 and 00:00 UT. Shortly after the spacecraft were located at perigee, the Cluster II satellites' magnetic footpoints move northwards over Scandinavia and Svalbard, almost perfectly aligned with the central chain of the IMAGE magnetometer network, and cross a morning sector ionospheric shear zone during this passage. In this study we focus on the mesoscale structure of the ionosphere. Ionospheric conductances, true horizontal currents, and field-aligned currents (FAC) are calculated from the ground-based measurements of the IMAGE magnetometers and the STARE coherent scatter radar, using the 1-D method of characteristics. An excellent agreement between these results and the FAC observed by Cluster II is reached after averaging the Cluster measurements to mesoscales, as well as between the location of the convection reversal boundary (CRB), as observed by STARE and by the Cluster II EFW instrument. A sheet of downward FAC is observed in the vicinity of the CRB, which is mainly caused by the positive divergence of the electric field there. This FAC sheet is detached by 0.5°–2° of latitude from a more equatorward downward FAC sheet at the poleward flank of the westward electrojet. This latter FAC sheet, as well as the upward FAC at the equatorward flank of the jet, are mainly caused by meridional gradients in the ionospheric conductances, which reach up to 25 S in the electrojet region, but only ~ 5 S poleward of it, with a minimum at the CRB. Particle measurements show that the major part of the downward FAC is carried by upward flowing electrons, and only a small part by downward flowing ions. The open-closed field line boundary is found to be located 3°–4° poleward of the CRB, implying significant errors if the latter is used as a proxy of the former. Article in Journal/Newspaper Fennoscandia Svalbard Institut national des sciences de l'Univers: HAL-INSU Svalbard |