First ground-based optical analysis of H ? Doppler profiles close to local noon in the cusp
International audience Observations of hydrogen emissions along the magnetic zenith at Longyearbyen (78.2 N, 15.8 E geographic) are used to investigate the energy and source of protons precipitating into the high latitude region. During the hours around local solar noon (11:00 UT), measurements of t...
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ftinsu:oai:HAL:hal-00318183v1 2023-11-12T04:20:43+01:00 First ground-based optical analysis of H ? Doppler profiles close to local noon in the cusp Robertson, S. C. Lanchester, B. S. Galand, M. Lummerzheim, D. Stockton-Chalk, A. B. Aylward, A. D. Furniss, I. Baumgardner, J. Space Environment Physics Atmospheric Physics Laboratory UCL London University College of London London (UCL) Space and Atmospheric Physics Group London Blackett Laboratory Imperial College London-Imperial College London Geophysical Institute Center for Space Physics Boston (CSP) Boston University Boston (BU) 2006-10-20 https://hal.science/hal-00318183 https://hal.science/hal-00318183/document https://hal.science/hal-00318183/file/angeo-24-2543-2006.pdf en eng HAL CCSD European Geosciences Union hal-00318183 https://hal.science/hal-00318183 https://hal.science/hal-00318183/document https://hal.science/hal-00318183/file/angeo-24-2543-2006.pdf info:eu-repo/semantics/OpenAccess ISSN: 0992-7689 EISSN: 1432-0576 Annales Geophysicae https://hal.science/hal-00318183 Annales Geophysicae, 2006, 24 (10), pp.2543-2552 [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 2006 ftinsu 2023-10-25T16:25:04Z International audience Observations of hydrogen emissions along the magnetic zenith at Longyearbyen (78.2 N, 15.8 E geographic) are used to investigate the energy and source of protons precipitating into the high latitude region. During the hours around local solar noon (11:00 UT), measurements of the hydrogen Balmer ? line are severely affected by sunlight, such that most data until now have been disregarded during these times. Here we use a simple technique to subtract sunlight contamination from such spectral data. An example is shown in which the removal of twilight contamination reveals a brightening of H ? aurora over Svalbard on 27 November 2000 between 08:00 UT and 10:00 UT, which is centred on magnetic noon (08:48 UT). These data were measured by the High Throughput Imaging Echelle Spectrograph (HiTIES), one instrument on the Southampton-UCL Spectrographic Imaging Facility (SIF). Data from the IMAGE satellite confirms the location of a cusp "spot" over Svalbard at the time of the ground-based measurements, which moved in response to changes in the IMF conditions. A coincident pass of the DMSP F12 satellite provided input spectra for modelling studies of the H ? profiles, which confirm that the method for removing the twilight contamination is robust. The results described here are the first ground-based optical measurements of H ? Doppler profiles from the cusp region close to local solar noon, when scattered sunlight swamps the raw data. Article in Journal/Newspaper Longyearbyen Svalbard Institut national des sciences de l'Univers: HAL-INSU Longyearbyen Svalbard |
institution |
Open Polar |
collection |
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 Robertson, S. C. Lanchester, B. S. Galand, M. Lummerzheim, D. Stockton-Chalk, A. B. Aylward, A. D. Furniss, I. Baumgardner, J. First ground-based optical analysis of H ? Doppler profiles close to local noon in the cusp |
topic_facet |
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU]Sciences of the Universe [physics]/Earth Sciences |
description |
International audience Observations of hydrogen emissions along the magnetic zenith at Longyearbyen (78.2 N, 15.8 E geographic) are used to investigate the energy and source of protons precipitating into the high latitude region. During the hours around local solar noon (11:00 UT), measurements of the hydrogen Balmer ? line are severely affected by sunlight, such that most data until now have been disregarded during these times. Here we use a simple technique to subtract sunlight contamination from such spectral data. An example is shown in which the removal of twilight contamination reveals a brightening of H ? aurora over Svalbard on 27 November 2000 between 08:00 UT and 10:00 UT, which is centred on magnetic noon (08:48 UT). These data were measured by the High Throughput Imaging Echelle Spectrograph (HiTIES), one instrument on the Southampton-UCL Spectrographic Imaging Facility (SIF). Data from the IMAGE satellite confirms the location of a cusp "spot" over Svalbard at the time of the ground-based measurements, which moved in response to changes in the IMF conditions. A coincident pass of the DMSP F12 satellite provided input spectra for modelling studies of the H ? profiles, which confirm that the method for removing the twilight contamination is robust. The results described here are the first ground-based optical measurements of H ? Doppler profiles from the cusp region close to local solar noon, when scattered sunlight swamps the raw data. |
author2 |
Space Environment Physics Atmospheric Physics Laboratory UCL London University College of London London (UCL) Space and Atmospheric Physics Group London Blackett Laboratory Imperial College London-Imperial College London Geophysical Institute Center for Space Physics Boston (CSP) Boston University Boston (BU) |
format |
Article in Journal/Newspaper |
author |
Robertson, S. C. Lanchester, B. S. Galand, M. Lummerzheim, D. Stockton-Chalk, A. B. Aylward, A. D. Furniss, I. Baumgardner, J. |
author_facet |
Robertson, S. C. Lanchester, B. S. Galand, M. Lummerzheim, D. Stockton-Chalk, A. B. Aylward, A. D. Furniss, I. Baumgardner, J. |
author_sort |
Robertson, S. C. |
title |
First ground-based optical analysis of H ? Doppler profiles close to local noon in the cusp |
title_short |
First ground-based optical analysis of H ? Doppler profiles close to local noon in the cusp |
title_full |
First ground-based optical analysis of H ? Doppler profiles close to local noon in the cusp |
title_fullStr |
First ground-based optical analysis of H ? Doppler profiles close to local noon in the cusp |
title_full_unstemmed |
First ground-based optical analysis of H ? Doppler profiles close to local noon in the cusp |
title_sort |
first ground-based optical analysis of h ? doppler profiles close to local noon in the cusp |
publisher |
HAL CCSD |
publishDate |
2006 |
url |
https://hal.science/hal-00318183 https://hal.science/hal-00318183/document https://hal.science/hal-00318183/file/angeo-24-2543-2006.pdf |
geographic |
Longyearbyen Svalbard |
geographic_facet |
Longyearbyen Svalbard |
genre |
Longyearbyen Svalbard |
genre_facet |
Longyearbyen Svalbard |
op_source |
ISSN: 0992-7689 EISSN: 1432-0576 Annales Geophysicae https://hal.science/hal-00318183 Annales Geophysicae, 2006, 24 (10), pp.2543-2552 |
op_relation |
hal-00318183 https://hal.science/hal-00318183 https://hal.science/hal-00318183/document https://hal.science/hal-00318183/file/angeo-24-2543-2006.pdf |
op_rights |
info:eu-repo/semantics/OpenAccess |
_version_ |
1782336522925637632 |