Nightside studies of coherent HF Radar spectral width behaviour
A previous case study found a relationship between high spectral width measured by the CUTLASS Finland HF radar and elevated electron temperatures observed by the EISCAT and ESR incoherent scatter radars in the post-midnight sector of magnetic local time. This paper expands that work by briefly re-e...
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ftleicesterunfig:oai:figshare.com:article/10145678 2023-05-15T16:04:42+02:00 Nightside studies of coherent HF Radar spectral width behaviour E. E. Woodfield J. A. Davies M. Lester T. K. Yeoman P. Eglitis M. Lockwood 2002-09-30T00:00:00Z https://figshare.com/articles/conference_contribution/Nightside_studies_of_coherent_HF_Radar_spectral_width_behaviour/10145678 unknown 2381/39286 https://figshare.com/articles/conference_contribution/Nightside_studies_of_coherent_HF_Radar_spectral_width_behaviour/10145678 All Rights Reserved Uncategorized Science & Technology Physical Sciences Astronomy & Astrophysics Geosciences Multidisciplinary Meteorology & Atmospheric Sciences Geology ionosphere auroral ionosphere ionospheric irregularities HIGH-LATITUDE CONVECTION EISCAT SVALBARD RADAR POLAR-CAP BOUNDARY F-REGION IONOSPHERIC CUSP PARTICLE-PRECIPITATION ISOLATED SUBSTORM PLASMA SUPERDARN SYSTEM Text Conference contribution 2002 ftleicesterunfig 2021-11-11T19:36:44Z A previous case study found a relationship between high spectral width measured by the CUTLASS Finland HF radar and elevated electron temperatures observed by the EISCAT and ESR incoherent scatter radars in the post-midnight sector of magnetic local time. This paper expands that work by briefly re-examining that interval and looking in depth at two further case studies. In all three cases a region of high HF spectral width (>200 ms-1) exists poleward of a region of low HF spectral width (<200 ms-1). Each case, however, occurs under quite different geomagnetic conditions. The original case study occurred during an interval with no observed electrojet activity, the second study during a transition from quiet to active conditions with a clear band of ion frictional heating indicating the location of the flow reversal boundary, and the third during an isolated sub-storm. These case studies indicate that the relationship between elevated electron temperature and high HF radar spectral width appears on closed field lines after 03:00 magnetic local time (MLT) on the nightside. It is not clear whether the same relationship would hold on open field lines, since our analysis of this relationship is restricted in latitude. We find two important properties of high spectral width data on the nightside. Firstly the high spectral width values occur on both open and closed field lines, and secondly that the power spectra which exhibit high widths are both single-peak and multiple-peak. In general the regions of high spectral width (>200 ms-1) have more multiple-peak spectra than the regions of low spectral widths whilst still maintaining a majority of single-peak spectra. We also find that the region of ion frictional heating is collocated with many multiple-peak HF spectra. Several mechanisms for the generation of high spectral width have been proposed which would produce multiple-peak spectra, these are discussed in relation to the data presented here. Since the regions of high spectral width are observed both on ... Conference Object EISCAT Svalbard University of Leicester: Figshare Svalbard |
institution |
Open Polar |
collection |
University of Leicester: Figshare |
op_collection_id |
ftleicesterunfig |
language |
unknown |
topic |
Uncategorized Science & Technology Physical Sciences Astronomy & Astrophysics Geosciences Multidisciplinary Meteorology & Atmospheric Sciences Geology ionosphere auroral ionosphere ionospheric irregularities HIGH-LATITUDE CONVECTION EISCAT SVALBARD RADAR POLAR-CAP BOUNDARY F-REGION IONOSPHERIC CUSP PARTICLE-PRECIPITATION ISOLATED SUBSTORM PLASMA SUPERDARN SYSTEM |
spellingShingle |
Uncategorized Science & Technology Physical Sciences Astronomy & Astrophysics Geosciences Multidisciplinary Meteorology & Atmospheric Sciences Geology ionosphere auroral ionosphere ionospheric irregularities HIGH-LATITUDE CONVECTION EISCAT SVALBARD RADAR POLAR-CAP BOUNDARY F-REGION IONOSPHERIC CUSP PARTICLE-PRECIPITATION ISOLATED SUBSTORM PLASMA SUPERDARN SYSTEM E. E. Woodfield J. A. Davies M. Lester T. K. Yeoman P. Eglitis M. Lockwood Nightside studies of coherent HF Radar spectral width behaviour |
topic_facet |
Uncategorized Science & Technology Physical Sciences Astronomy & Astrophysics Geosciences Multidisciplinary Meteorology & Atmospheric Sciences Geology ionosphere auroral ionosphere ionospheric irregularities HIGH-LATITUDE CONVECTION EISCAT SVALBARD RADAR POLAR-CAP BOUNDARY F-REGION IONOSPHERIC CUSP PARTICLE-PRECIPITATION ISOLATED SUBSTORM PLASMA SUPERDARN SYSTEM |
description |
A previous case study found a relationship between high spectral width measured by the CUTLASS Finland HF radar and elevated electron temperatures observed by the EISCAT and ESR incoherent scatter radars in the post-midnight sector of magnetic local time. This paper expands that work by briefly re-examining that interval and looking in depth at two further case studies. In all three cases a region of high HF spectral width (>200 ms-1) exists poleward of a region of low HF spectral width (<200 ms-1). Each case, however, occurs under quite different geomagnetic conditions. The original case study occurred during an interval with no observed electrojet activity, the second study during a transition from quiet to active conditions with a clear band of ion frictional heating indicating the location of the flow reversal boundary, and the third during an isolated sub-storm. These case studies indicate that the relationship between elevated electron temperature and high HF radar spectral width appears on closed field lines after 03:00 magnetic local time (MLT) on the nightside. It is not clear whether the same relationship would hold on open field lines, since our analysis of this relationship is restricted in latitude. We find two important properties of high spectral width data on the nightside. Firstly the high spectral width values occur on both open and closed field lines, and secondly that the power spectra which exhibit high widths are both single-peak and multiple-peak. In general the regions of high spectral width (>200 ms-1) have more multiple-peak spectra than the regions of low spectral widths whilst still maintaining a majority of single-peak spectra. We also find that the region of ion frictional heating is collocated with many multiple-peak HF spectra. Several mechanisms for the generation of high spectral width have been proposed which would produce multiple-peak spectra, these are discussed in relation to the data presented here. Since the regions of high spectral width are observed both on ... |
format |
Conference Object |
author |
E. E. Woodfield J. A. Davies M. Lester T. K. Yeoman P. Eglitis M. Lockwood |
author_facet |
E. E. Woodfield J. A. Davies M. Lester T. K. Yeoman P. Eglitis M. Lockwood |
author_sort |
E. E. Woodfield |
title |
Nightside studies of coherent HF Radar spectral width behaviour |
title_short |
Nightside studies of coherent HF Radar spectral width behaviour |
title_full |
Nightside studies of coherent HF Radar spectral width behaviour |
title_fullStr |
Nightside studies of coherent HF Radar spectral width behaviour |
title_full_unstemmed |
Nightside studies of coherent HF Radar spectral width behaviour |
title_sort |
nightside studies of coherent hf radar spectral width behaviour |
publishDate |
2002 |
url |
https://figshare.com/articles/conference_contribution/Nightside_studies_of_coherent_HF_Radar_spectral_width_behaviour/10145678 |
geographic |
Svalbard |
geographic_facet |
Svalbard |
genre |
EISCAT Svalbard |
genre_facet |
EISCAT Svalbard |
op_relation |
2381/39286 https://figshare.com/articles/conference_contribution/Nightside_studies_of_coherent_HF_Radar_spectral_width_behaviour/10145678 |
op_rights |
All Rights Reserved |
_version_ |
1766400316997107712 |