An inter-hemispheric, statistical study of nightside spectral width distributions from coherent HF scatter radars

A statistical investigation of the Doppler spectral width parameter routinely observed by HF coherent radars has been conducted between the Northern and Southern Hemispheres for the nightside ionosphere. Data from the SuperDARN radars at Thykkvibær, Iceland and Syowa East, Antarctica have been emplo...

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Published in:Annales Geophysicae
Main Authors: E. E. Woodfield, K. Hosokawa, S. E. Milan, N. Sato, M. Lester
Format: Article in Journal/Newspaper
Language:English
Published: Copernicus Publications 2002
Subjects:
Q
Online Access:https://doi.org/10.5194/angeo-20-1921-2002
https://doaj.org/article/172384b08b734dd38a4a299a33de5407
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spelling ftdoajarticles:oai:doaj.org/article:172384b08b734dd38a4a299a33de5407 2023-05-15T13:34:40+02:00 An inter-hemispheric, statistical study of nightside spectral width distributions from coherent HF scatter radars E. E. Woodfield K. Hosokawa S. E. Milan N. Sato M. Lester 2002-12-01T00:00:00Z https://doi.org/10.5194/angeo-20-1921-2002 https://doaj.org/article/172384b08b734dd38a4a299a33de5407 EN eng Copernicus Publications https://www.ann-geophys.net/20/1921/2002/angeo-20-1921-2002.pdf https://doaj.org/toc/0992-7689 https://doaj.org/toc/1432-0576 doi:10.5194/angeo-20-1921-2002 0992-7689 1432-0576 https://doaj.org/article/172384b08b734dd38a4a299a33de5407 Annales Geophysicae, Vol 20, Pp 1921-1934 (2002) Science Q Physics QC1-999 Geophysics. Cosmic physics QC801-809 article 2002 ftdoajarticles https://doi.org/10.5194/angeo-20-1921-2002 2022-12-30T22:32:49Z A statistical investigation of the Doppler spectral width parameter routinely observed by HF coherent radars has been conducted between the Northern and Southern Hemispheres for the nightside ionosphere. Data from the SuperDARN radars at Thykkvibær, Iceland and Syowa East, Antarctica have been employed for this purpose. Both radars frequently observe regions of high (>200 ms -1 ) spectral width polewards of low (<200 ms -1 ) spectral width. Three years of data from both radars have been analysed both for the spectral width and line of sight velocity. The pointing direction of these two radars is such that the flow reversal boundary may be estimated from the velocity data, and therefore, we have an estimate of the open/closed field line boundary location for comparison with the high spectral widths. Five key observations regarding the behaviour of the spectral width on the nightside have been made. These are (i) the two radars observe similar characteristics on a statistical basis; (ii) a latitudinal dependence related to magnetic local time is found in both hemispheres; (iii) a seasonal dependence of the spectral width is observed by both radars, which shows a marked absence of latitudinal dependence during the summer months; (iv) in general, the Syowa East spectral width tends to be larger than that from Iceland East, and (v) the highest spectral widths seem to appear on both open and closed field lines. Points (i) and (ii) indicate that the cause of high spectral width is magnetospheric in origin. Point (iii) suggests that either the propagation of the HF radio waves to regions of high spectral width or the generating mechanism(s) for high spectral width is affected by solar illumination or other seasonal effects. Point (iv) suggests that the radar beams from each of the radars are subject either to different instrumental or propagation effects, or different geophysical conditions due to their locations, although we suggest that this result is more likely to be due to geophysical effects. Point (v) leads ... Article in Journal/Newspaper Antarc* Antarctica East Antarctica Iceland Directory of Open Access Journals: DOAJ Articles East Antarctica Annales Geophysicae 20 12 1921 1934
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. E. Woodfield
K. Hosokawa
S. E. Milan
N. Sato
M. Lester
An inter-hemispheric, statistical study of nightside spectral width distributions from coherent HF scatter radars
topic_facet Science
Q
Physics
QC1-999
Geophysics. Cosmic physics
QC801-809
description A statistical investigation of the Doppler spectral width parameter routinely observed by HF coherent radars has been conducted between the Northern and Southern Hemispheres for the nightside ionosphere. Data from the SuperDARN radars at Thykkvibær, Iceland and Syowa East, Antarctica have been employed for this purpose. Both radars frequently observe regions of high (>200 ms -1 ) spectral width polewards of low (<200 ms -1 ) spectral width. Three years of data from both radars have been analysed both for the spectral width and line of sight velocity. The pointing direction of these two radars is such that the flow reversal boundary may be estimated from the velocity data, and therefore, we have an estimate of the open/closed field line boundary location for comparison with the high spectral widths. Five key observations regarding the behaviour of the spectral width on the nightside have been made. These are (i) the two radars observe similar characteristics on a statistical basis; (ii) a latitudinal dependence related to magnetic local time is found in both hemispheres; (iii) a seasonal dependence of the spectral width is observed by both radars, which shows a marked absence of latitudinal dependence during the summer months; (iv) in general, the Syowa East spectral width tends to be larger than that from Iceland East, and (v) the highest spectral widths seem to appear on both open and closed field lines. Points (i) and (ii) indicate that the cause of high spectral width is magnetospheric in origin. Point (iii) suggests that either the propagation of the HF radio waves to regions of high spectral width or the generating mechanism(s) for high spectral width is affected by solar illumination or other seasonal effects. Point (iv) suggests that the radar beams from each of the radars are subject either to different instrumental or propagation effects, or different geophysical conditions due to their locations, although we suggest that this result is more likely to be due to geophysical effects. Point (v) leads ...
format Article in Journal/Newspaper
author E. E. Woodfield
K. Hosokawa
S. E. Milan
N. Sato
M. Lester
author_facet E. E. Woodfield
K. Hosokawa
S. E. Milan
N. Sato
M. Lester
author_sort E. E. Woodfield
title An inter-hemispheric, statistical study of nightside spectral width distributions from coherent HF scatter radars
title_short An inter-hemispheric, statistical study of nightside spectral width distributions from coherent HF scatter radars
title_full An inter-hemispheric, statistical study of nightside spectral width distributions from coherent HF scatter radars
title_fullStr An inter-hemispheric, statistical study of nightside spectral width distributions from coherent HF scatter radars
title_full_unstemmed An inter-hemispheric, statistical study of nightside spectral width distributions from coherent HF scatter radars
title_sort inter-hemispheric, statistical study of nightside spectral width distributions from coherent hf scatter radars
publisher Copernicus Publications
publishDate 2002
url https://doi.org/10.5194/angeo-20-1921-2002
https://doaj.org/article/172384b08b734dd38a4a299a33de5407
geographic East Antarctica
geographic_facet East Antarctica
genre Antarc*
Antarctica
East Antarctica
Iceland
genre_facet Antarc*
Antarctica
East Antarctica
Iceland
op_source Annales Geophysicae, Vol 20, Pp 1921-1934 (2002)
op_relation https://www.ann-geophys.net/20/1921/2002/angeo-20-1921-2002.pdf
https://doaj.org/toc/0992-7689
https://doaj.org/toc/1432-0576
doi:10.5194/angeo-20-1921-2002
0992-7689
1432-0576
https://doaj.org/article/172384b08b734dd38a4a299a33de5407
op_doi https://doi.org/10.5194/angeo-20-1921-2002
container_title Annales Geophysicae
container_volume 20
container_issue 12
container_start_page 1921
op_container_end_page 1934
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