Upper thermospheric neutral wind and temperature measurements from an extended spatial field
First results are presented from a Scanning Doppler Imager (SCANDI) installed at the Nordlysstasjonen optical observatory near Longyearbyen, Svalbard (78.2° N, 15.8° E). Observations of the atomic oxygen 630 nm red line emission, originating in the upper thermosphere at around 250 km, have been used...
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Copernicus Publications
2008
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ftnonlinearchiv:oai:noa.gwlb.de:cop_mods_00031128 2023-05-15T16:04:48+02:00 Upper thermospheric neutral wind and temperature measurements from an extended spatial field Griffin, E. M. Aruliah, A. L. McWhirter, I. Yiu, H.-C. I. Charalambous, A. McCrea, I. 2008-09 electronic https://doi.org/10.5194/angeo-26-2649-2008 https://noa.gwlb.de/receive/cop_mods_00031128 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00031082/angeo-26-2649-2008.pdf https://angeo.copernicus.org/articles/26/2649/2008/angeo-26-2649-2008.pdf eng eng Copernicus Publications Annales Geophysicae -- http://www.bibliothek.uni-regensburg.de/ezeit/?1458425 -- https://www.ann-geophys.net/ -- https://www.ann-geophys.net/volumes.html -- http://link.springer.com/journal/585 -- 1432-0576 https://doi.org/10.5194/angeo-26-2649-2008 https://noa.gwlb.de/receive/cop_mods_00031128 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00031082/angeo-26-2649-2008.pdf https://angeo.copernicus.org/articles/26/2649/2008/angeo-26-2649-2008.pdf uneingeschränkt info:eu-repo/semantics/openAccess article Verlagsveröffentlichung article Text doc-type:article 2008 ftnonlinearchiv https://doi.org/10.5194/angeo-26-2649-2008 2022-02-08T22:46:52Z First results are presented from a Scanning Doppler Imager (SCANDI) installed at the Nordlysstasjonen optical observatory near Longyearbyen, Svalbard (78.2° N, 15.8° E). Observations of the atomic oxygen 630 nm red line emission, originating in the upper thermosphere at around 250 km, have been used to determine neutral winds and temperatures from multiple zones within an extended spatial field. The instrument utilises all-sky optics to achieve multiple simultaneous measurements, compared to the standard Fabry-Perot Interferometer (FPI) procedure of separate line-of-sight samples within a sequence of narrow angle look directions. SCANDI is colocated with such a standard FPI and comparison of neutral wind velocities between the instruments on the night of 15 March 2007 has revealed detailed and consistent structure in the wind field. Southward meridional wind enhancements of several hundred m/s are observed simultaneously with both instruments, revealing structure on scales not currently considered in thermospheric general circulation models (GCMs). The data from this night also demonstrate the influence of discrete auroral events on thermospheric behaviour. High intensities observed by SCANDI in the presence of auroral arcs coincide with a drop in measured neutral temperatures. This is interpreted as a result of the effective altitude of the 630 nm emission being lowered under conditions of soft auroral precipitation. The optical instruments as a consequence sample a region of lower temperature. This effect has been observed previously with lower thermospheric atomic oxygen emissions at 557.7 nm. The EISCAT Svalbard Radar (ESR) provides ion temperatures and electron densities for the night which confirm the influence of precipitation and heating during the auroral events. The minima of ion temperatures through the pre-midnight period provide a good match to the neutral temperatures measured with SCANDI, and to the colocated FPI temperatures. Article in Journal/Newspaper EISCAT Longyearbyen Svalbard Niedersächsisches Online-Archiv NOA Svalbard Longyearbyen Annales Geophysicae 26 9 2649 2655 |
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Niedersächsisches Online-Archiv NOA |
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ftnonlinearchiv |
language |
English |
topic |
article Verlagsveröffentlichung |
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article Verlagsveröffentlichung Griffin, E. M. Aruliah, A. L. McWhirter, I. Yiu, H.-C. I. Charalambous, A. McCrea, I. Upper thermospheric neutral wind and temperature measurements from an extended spatial field |
topic_facet |
article Verlagsveröffentlichung |
description |
First results are presented from a Scanning Doppler Imager (SCANDI) installed at the Nordlysstasjonen optical observatory near Longyearbyen, Svalbard (78.2° N, 15.8° E). Observations of the atomic oxygen 630 nm red line emission, originating in the upper thermosphere at around 250 km, have been used to determine neutral winds and temperatures from multiple zones within an extended spatial field. The instrument utilises all-sky optics to achieve multiple simultaneous measurements, compared to the standard Fabry-Perot Interferometer (FPI) procedure of separate line-of-sight samples within a sequence of narrow angle look directions. SCANDI is colocated with such a standard FPI and comparison of neutral wind velocities between the instruments on the night of 15 March 2007 has revealed detailed and consistent structure in the wind field. Southward meridional wind enhancements of several hundred m/s are observed simultaneously with both instruments, revealing structure on scales not currently considered in thermospheric general circulation models (GCMs). The data from this night also demonstrate the influence of discrete auroral events on thermospheric behaviour. High intensities observed by SCANDI in the presence of auroral arcs coincide with a drop in measured neutral temperatures. This is interpreted as a result of the effective altitude of the 630 nm emission being lowered under conditions of soft auroral precipitation. The optical instruments as a consequence sample a region of lower temperature. This effect has been observed previously with lower thermospheric atomic oxygen emissions at 557.7 nm. The EISCAT Svalbard Radar (ESR) provides ion temperatures and electron densities for the night which confirm the influence of precipitation and heating during the auroral events. The minima of ion temperatures through the pre-midnight period provide a good match to the neutral temperatures measured with SCANDI, and to the colocated FPI temperatures. |
format |
Article in Journal/Newspaper |
author |
Griffin, E. M. Aruliah, A. L. McWhirter, I. Yiu, H.-C. I. Charalambous, A. McCrea, I. |
author_facet |
Griffin, E. M. Aruliah, A. L. McWhirter, I. Yiu, H.-C. I. Charalambous, A. McCrea, I. |
author_sort |
Griffin, E. M. |
title |
Upper thermospheric neutral wind and temperature measurements from an extended spatial field |
title_short |
Upper thermospheric neutral wind and temperature measurements from an extended spatial field |
title_full |
Upper thermospheric neutral wind and temperature measurements from an extended spatial field |
title_fullStr |
Upper thermospheric neutral wind and temperature measurements from an extended spatial field |
title_full_unstemmed |
Upper thermospheric neutral wind and temperature measurements from an extended spatial field |
title_sort |
upper thermospheric neutral wind and temperature measurements from an extended spatial field |
publisher |
Copernicus Publications |
publishDate |
2008 |
url |
https://doi.org/10.5194/angeo-26-2649-2008 https://noa.gwlb.de/receive/cop_mods_00031128 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00031082/angeo-26-2649-2008.pdf https://angeo.copernicus.org/articles/26/2649/2008/angeo-26-2649-2008.pdf |
geographic |
Svalbard Longyearbyen |
geographic_facet |
Svalbard Longyearbyen |
genre |
EISCAT Longyearbyen Svalbard |
genre_facet |
EISCAT Longyearbyen Svalbard |
op_relation |
Annales Geophysicae -- http://www.bibliothek.uni-regensburg.de/ezeit/?1458425 -- https://www.ann-geophys.net/ -- https://www.ann-geophys.net/volumes.html -- http://link.springer.com/journal/585 -- 1432-0576 https://doi.org/10.5194/angeo-26-2649-2008 https://noa.gwlb.de/receive/cop_mods_00031128 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00031082/angeo-26-2649-2008.pdf https://angeo.copernicus.org/articles/26/2649/2008/angeo-26-2649-2008.pdf |
op_rights |
uneingeschränkt info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.5194/angeo-26-2649-2008 |
container_title |
Annales Geophysicae |
container_volume |
26 |
container_issue |
9 |
container_start_page |
2649 |
op_container_end_page |
2655 |
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1766400427734073344 |