Variations of VLF Wave Intensity Analyzed via Principal Component Analysis
International audience Wave intensity measured in the very low frequency (VLF) range (up to 20 kHz) is typically represented using frequency-time spectrograms. Since the characterization of spectrogram main features and/or their direct comparison is a challenging task, we transform the measurements...
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ftobservparis:oai:HAL:insu-03559378v1 2024-09-15T18:25:40+00:00 Variations of VLF Wave Intensity Analyzed via Principal Component Analysis Bezděková, Barbora Němec, František Parrot, Michel Manninen, Jyrki Krupařová, Oksana Laboratoire de Physique et Chimie de l'Environnement et de l'Espace (LPC2E) Observatoire des Sciences de l'Univers en région Centre (OSUC) Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales Paris (CNES) online, France 2021 https://insu.hal.science/insu-03559378 https://insu.hal.science/insu-03559378/document https://insu.hal.science/insu-03559378/file/EGU21-2805-print.pdf https://doi.org/10.5194/egusphere-egu21-2805 en eng HAL CCSD info:eu-repo/semantics/altIdentifier/doi/10.5194/egusphere-egu21-2805 insu-03559378 https://insu.hal.science/insu-03559378 https://insu.hal.science/insu-03559378/document https://insu.hal.science/insu-03559378/file/EGU21-2805-print.pdf BIBCODE: 2021EGUGA.23.2805B doi:10.5194/egusphere-egu21-2805 http://creativecommons.org/licenses/by/ info:eu-repo/semantics/OpenAccess vEGU21 https://insu.hal.science/insu-03559378 vEGU21, 2021, online, France. ⟨10.5194/egusphere-egu21-2805⟩ [SDU]Sciences of the Universe [physics] info:eu-repo/semantics/conferenceObject Conference papers 2021 ftobservparis https://doi.org/10.5194/egusphere-egu21-2805 2024-06-25T00:01:25Z International audience Wave intensity measured in the very low frequency (VLF) range (up to 20 kHz) is typically represented using frequency-time spectrograms. Since the characterization of spectrogram main features and/or their direct comparison is a challenging task, we transform the measurements of the low-altitude DEMETER spacecraft using the principal component analysis (PCA). The present study is focused on both the physical interpretation of the first two principal components and their application to real physical problems. To understand the physical meaning of the first principal components, their scatter plot is constructed and discussed. Moreover, the dependence of the first principal component (PC1) coefficients on the geomagnetic activity and their seasonal/longitudinal variations are analyzed. The obtained distributions are well comparable with those obtained by previous studies for average wave intensities, indicating that the PC1 coefficients are directly related to the overall wave intensity. Furthermore, the variations of PC1 coefficients around interplanetary (IP) shock arrivals are analyzed, suggesting that the fast forward shock occurrence has the most significant effect. It is shown that the wave intensity variations depend on the wave intensity detected before the shock arrival. The shock strength and interplanetary magnetic field orientation are also important. To further demonstrate the adaptability of PCA, we use a similar method to analyze also ground-based VLF measurements performed by the Kannuslehto station located in northern Finland. Conference Object Northern Finland Archive de l'Observatoire de Paris (HAL) |
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Open Polar |
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Archive de l'Observatoire de Paris (HAL) |
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ftobservparis |
language |
English |
topic |
[SDU]Sciences of the Universe [physics] |
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[SDU]Sciences of the Universe [physics] Bezděková, Barbora Němec, František Parrot, Michel Manninen, Jyrki Krupařová, Oksana Variations of VLF Wave Intensity Analyzed via Principal Component Analysis |
topic_facet |
[SDU]Sciences of the Universe [physics] |
description |
International audience Wave intensity measured in the very low frequency (VLF) range (up to 20 kHz) is typically represented using frequency-time spectrograms. Since the characterization of spectrogram main features and/or their direct comparison is a challenging task, we transform the measurements of the low-altitude DEMETER spacecraft using the principal component analysis (PCA). The present study is focused on both the physical interpretation of the first two principal components and their application to real physical problems. To understand the physical meaning of the first principal components, their scatter plot is constructed and discussed. Moreover, the dependence of the first principal component (PC1) coefficients on the geomagnetic activity and their seasonal/longitudinal variations are analyzed. The obtained distributions are well comparable with those obtained by previous studies for average wave intensities, indicating that the PC1 coefficients are directly related to the overall wave intensity. Furthermore, the variations of PC1 coefficients around interplanetary (IP) shock arrivals are analyzed, suggesting that the fast forward shock occurrence has the most significant effect. It is shown that the wave intensity variations depend on the wave intensity detected before the shock arrival. The shock strength and interplanetary magnetic field orientation are also important. To further demonstrate the adaptability of PCA, we use a similar method to analyze also ground-based VLF measurements performed by the Kannuslehto station located in northern Finland. |
author2 |
Laboratoire de Physique et Chimie de l'Environnement et de l'Espace (LPC2E) Observatoire des Sciences de l'Univers en région Centre (OSUC) Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales Paris (CNES) |
format |
Conference Object |
author |
Bezděková, Barbora Němec, František Parrot, Michel Manninen, Jyrki Krupařová, Oksana |
author_facet |
Bezděková, Barbora Němec, František Parrot, Michel Manninen, Jyrki Krupařová, Oksana |
author_sort |
Bezděková, Barbora |
title |
Variations of VLF Wave Intensity Analyzed via Principal Component Analysis |
title_short |
Variations of VLF Wave Intensity Analyzed via Principal Component Analysis |
title_full |
Variations of VLF Wave Intensity Analyzed via Principal Component Analysis |
title_fullStr |
Variations of VLF Wave Intensity Analyzed via Principal Component Analysis |
title_full_unstemmed |
Variations of VLF Wave Intensity Analyzed via Principal Component Analysis |
title_sort |
variations of vlf wave intensity analyzed via principal component analysis |
publisher |
HAL CCSD |
publishDate |
2021 |
url |
https://insu.hal.science/insu-03559378 https://insu.hal.science/insu-03559378/document https://insu.hal.science/insu-03559378/file/EGU21-2805-print.pdf https://doi.org/10.5194/egusphere-egu21-2805 |
op_coverage |
online, France |
genre |
Northern Finland |
genre_facet |
Northern Finland |
op_source |
vEGU21 https://insu.hal.science/insu-03559378 vEGU21, 2021, online, France. ⟨10.5194/egusphere-egu21-2805⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.5194/egusphere-egu21-2805 insu-03559378 https://insu.hal.science/insu-03559378 https://insu.hal.science/insu-03559378/document https://insu.hal.science/insu-03559378/file/EGU21-2805-print.pdf BIBCODE: 2021EGUGA.23.2805B doi:10.5194/egusphere-egu21-2805 |
op_rights |
http://creativecommons.org/licenses/by/ info:eu-repo/semantics/OpenAccess |
op_doi |
https://doi.org/10.5194/egusphere-egu21-2805 |
_version_ |
1810466158865809408 |