Simultaneous FPI and TMA measurements of the lower thermospheric wind in the vicinity of the poleward expanding aurora after substorm onset
Abstract Lower thermospheric wind fluctuations in the vicinity of an auroral arc immediately before and after a substorm onset were examined by analyzing data from a ground‐based green line Fabry‐Perot interferometer (FPI; optical wavelength of 557.7 nm) at Tromsø, Norway, and in situ measurements f...
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ftunivoulu:oai:oulu.fi:nbnfi-fe201902215930 2023-07-30T04:07:18+02:00 Simultaneous FPI and TMA measurements of the lower thermospheric wind in the vicinity of the poleward expanding aurora after substorm onset Oyama, S.-i. (Shin-ichiro) Kubota, K. (Ken) Morinaga, T. (Takatoshi) Tsuda, T. T. (Takuo T.) Kurihara, J. (Junichi) Larsen, M. F. (Miguel F.) Yamamoto, M. (Masayuki) Cai, L. (Lei) 2017 application/pdf http://urn.fi/urn:nbn:fi-fe201902215930 eng eng American Geophysical Union info:eu-repo/semantics/openAccess © 2017. American Geophysical Union. All Rights Reserved. info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion 2017 ftunivoulu 2023-07-08T19:55:26Z Abstract Lower thermospheric wind fluctuations in the vicinity of an auroral arc immediately before and after a substorm onset were examined by analyzing data from a ground‐based green line Fabry‐Perot interferometer (FPI; optical wavelength of 557.7 nm) at Tromsø, Norway, and in situ measurements from a trimethyl aluminum (TMA) trail released from a sounding rocket launched during the Dynamics and Energetics of the Lower Thermosphere in Aurora 2 (DELTA‐2) campaign on 26 January 2009. Soon after the rocket launch but before disappearance of the TMA trail, a substorm onset occurred. The DELTA‐2 TMA experiment appears to be the first case in which the substorm onset occurred during the TMA wind measurement. It is known that energy dissipation induced by the ionospheric closure current is compacted at the poleward side of the discrete arc in the ionospheric morning cell. Both FPI and TMA measurements were made at the poleward side, but the FPI measured winds nearer to the poleward edge of the arc than the TMA by 110–130 km. The FPI winds at distance of 53–74 km relative to the arc edge showed clear fluctuations immediately after the substorm onset, but there was no obvious similar fluctuation in the TMA‐measured winds. The difference in the response at the two locations suggests that energy dissipation sufficient to be detected as the FPI/TMA wind perturbations was confined to the area from the poleward edge of the arc to a relative distance shorter than 163–203 km but longer than 53–74 km in this event. Article in Journal/Newspaper Tromsø Jultika - University of Oulu repository Norway Tromsø |
institution |
Open Polar |
collection |
Jultika - University of Oulu repository |
op_collection_id |
ftunivoulu |
language |
English |
description |
Abstract Lower thermospheric wind fluctuations in the vicinity of an auroral arc immediately before and after a substorm onset were examined by analyzing data from a ground‐based green line Fabry‐Perot interferometer (FPI; optical wavelength of 557.7 nm) at Tromsø, Norway, and in situ measurements from a trimethyl aluminum (TMA) trail released from a sounding rocket launched during the Dynamics and Energetics of the Lower Thermosphere in Aurora 2 (DELTA‐2) campaign on 26 January 2009. Soon after the rocket launch but before disappearance of the TMA trail, a substorm onset occurred. The DELTA‐2 TMA experiment appears to be the first case in which the substorm onset occurred during the TMA wind measurement. It is known that energy dissipation induced by the ionospheric closure current is compacted at the poleward side of the discrete arc in the ionospheric morning cell. Both FPI and TMA measurements were made at the poleward side, but the FPI measured winds nearer to the poleward edge of the arc than the TMA by 110–130 km. The FPI winds at distance of 53–74 km relative to the arc edge showed clear fluctuations immediately after the substorm onset, but there was no obvious similar fluctuation in the TMA‐measured winds. The difference in the response at the two locations suggests that energy dissipation sufficient to be detected as the FPI/TMA wind perturbations was confined to the area from the poleward edge of the arc to a relative distance shorter than 163–203 km but longer than 53–74 km in this event. |
format |
Article in Journal/Newspaper |
author |
Oyama, S.-i. (Shin-ichiro) Kubota, K. (Ken) Morinaga, T. (Takatoshi) Tsuda, T. T. (Takuo T.) Kurihara, J. (Junichi) Larsen, M. F. (Miguel F.) Yamamoto, M. (Masayuki) Cai, L. (Lei) |
spellingShingle |
Oyama, S.-i. (Shin-ichiro) Kubota, K. (Ken) Morinaga, T. (Takatoshi) Tsuda, T. T. (Takuo T.) Kurihara, J. (Junichi) Larsen, M. F. (Miguel F.) Yamamoto, M. (Masayuki) Cai, L. (Lei) Simultaneous FPI and TMA measurements of the lower thermospheric wind in the vicinity of the poleward expanding aurora after substorm onset |
author_facet |
Oyama, S.-i. (Shin-ichiro) Kubota, K. (Ken) Morinaga, T. (Takatoshi) Tsuda, T. T. (Takuo T.) Kurihara, J. (Junichi) Larsen, M. F. (Miguel F.) Yamamoto, M. (Masayuki) Cai, L. (Lei) |
author_sort |
Oyama, S.-i. (Shin-ichiro) |
title |
Simultaneous FPI and TMA measurements of the lower thermospheric wind in the vicinity of the poleward expanding aurora after substorm onset |
title_short |
Simultaneous FPI and TMA measurements of the lower thermospheric wind in the vicinity of the poleward expanding aurora after substorm onset |
title_full |
Simultaneous FPI and TMA measurements of the lower thermospheric wind in the vicinity of the poleward expanding aurora after substorm onset |
title_fullStr |
Simultaneous FPI and TMA measurements of the lower thermospheric wind in the vicinity of the poleward expanding aurora after substorm onset |
title_full_unstemmed |
Simultaneous FPI and TMA measurements of the lower thermospheric wind in the vicinity of the poleward expanding aurora after substorm onset |
title_sort |
simultaneous fpi and tma measurements of the lower thermospheric wind in the vicinity of the poleward expanding aurora after substorm onset |
publisher |
American Geophysical Union |
publishDate |
2017 |
url |
http://urn.fi/urn:nbn:fi-fe201902215930 |
geographic |
Norway Tromsø |
geographic_facet |
Norway Tromsø |
genre |
Tromsø |
genre_facet |
Tromsø |
op_rights |
info:eu-repo/semantics/openAccess © 2017. American Geophysical Union. All Rights Reserved. |
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1772820549972525056 |