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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ftdoajarticles:oai:doaj.org/article:bd6ed1a761bd4aa0a269b324d46a4105 2023-05-15T16:04:49+02:00 Upper thermospheric neutral wind and temperature measurements from an extended spatial field E. M. Griffin A. L. Aruliah I. McWhirter H.-C. I. Yiu A. Charalambous I. McCrea 2008-09-01T00:00:00Z https://doi.org/10.5194/angeo-26-2649-2008 https://doaj.org/article/bd6ed1a761bd4aa0a269b324d46a4105 EN eng Copernicus Publications https://www.ann-geophys.net/26/2649/2008/angeo-26-2649-2008.pdf https://doaj.org/toc/0992-7689 https://doaj.org/toc/1432-0576 doi:10.5194/angeo-26-2649-2008 0992-7689 1432-0576 https://doaj.org/article/bd6ed1a761bd4aa0a269b324d46a4105 Annales Geophysicae, Vol 26, Pp 2649-2655 (2008) Science Q Physics QC1-999 Geophysics. Cosmic physics QC801-809 article 2008 ftdoajarticles https://doi.org/10.5194/angeo-26-2649-2008 2022-12-31T15:37:35Z 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 Directory of Open Access Journals: DOAJ Articles Svalbard Longyearbyen Annales Geophysicae 26 9 2649 2655 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Science Q Physics QC1-999 Geophysics. Cosmic physics QC801-809 |
spellingShingle |
Science Q Physics QC1-999 Geophysics. Cosmic physics QC801-809 E. M. Griffin A. L. Aruliah I. McWhirter H.-C. I. Yiu A. Charalambous I. McCrea Upper thermospheric neutral wind and temperature measurements from an extended spatial field |
topic_facet |
Science Q Physics QC1-999 Geophysics. Cosmic physics QC801-809 |
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 |
E. M. Griffin A. L. Aruliah I. McWhirter H.-C. I. Yiu A. Charalambous I. McCrea |
author_facet |
E. M. Griffin A. L. Aruliah I. McWhirter H.-C. I. Yiu A. Charalambous I. McCrea |
author_sort |
E. M. Griffin |
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://doaj.org/article/bd6ed1a761bd4aa0a269b324d46a4105 |
geographic |
Svalbard Longyearbyen |
geographic_facet |
Svalbard Longyearbyen |
genre |
EISCAT Longyearbyen Svalbard |
genre_facet |
EISCAT Longyearbyen Svalbard |
op_source |
Annales Geophysicae, Vol 26, Pp 2649-2655 (2008) |
op_relation |
https://www.ann-geophys.net/26/2649/2008/angeo-26-2649-2008.pdf https://doaj.org/toc/0992-7689 https://doaj.org/toc/1432-0576 doi:10.5194/angeo-26-2649-2008 0992-7689 1432-0576 https://doaj.org/article/bd6ed1a761bd4aa0a269b324d46a4105 |
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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1766400456374878208 |