Sunrise effects on VLF signals propagating over a long north-south path
We present a detailed study of the times of amplitude minima observed on the 12-Mm path from NAA (24 kHz, 1 MW, Cutler, Maine) to Faraday, Antarctica, during the period 1990–1995. (NAA is a naval transmitter call sign.) This study represents the first account of the effect of the sunrise terminator...
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American Geophysical Union
1999
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Online Access: | http://nora.nerc.ac.uk/id/eprint/503087/ https://doi.org/10.1029/1999RS900052 |
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ftnerc:oai:nora.nerc.ac.uk:503087 2023-05-15T13:48:07+02:00 Sunrise effects on VLF signals propagating over a long north-south path Clilverd, Mark A. Thomson, Neil R. Rodger, Craig J. 1999 http://nora.nerc.ac.uk/id/eprint/503087/ https://doi.org/10.1029/1999RS900052 unknown American Geophysical Union Clilverd, Mark A. orcid:0000-0002-7388-1529 Thomson, Neil R.; Rodger, Craig J. 1999 Sunrise effects on VLF signals propagating over a long north-south path. Radio Science, 34 (4). 939-948. https://doi.org/10.1029/1999RS900052 <https://doi.org/10.1029/1999RS900052> Publication - Article PeerReviewed 1999 ftnerc https://doi.org/10.1029/1999RS900052 2023-02-04T19:37:38Z We present a detailed study of the times of amplitude minima observed on the 12-Mm path from NAA (24 kHz, 1 MW, Cutler, Maine) to Faraday, Antarctica, during the period 1990–1995. (NAA is a naval transmitter call sign.) This study represents the first account of the effect of the sunrise terminator when it is parallel to a propagation path at some times of the year. Since the NAA-Faraday path is within 3° of the north-south meridian, parallel orientation happens close to the equinoxes, while the maximum angle of incidence occurs during the solstices. During the solstices the terminator takes a significant length of time to cross the entire propagation path, so modal conversion effects are observed over a range of hours. During the equinoxes, however, the leading edge of the night-day transition region crosses the whole propagation path within 20 min. The interpretation of the timing of minima is consistent with modal conversion taking place as the sunrise terminator crosses the NAA-Faraday transmission path at specific, consistent locations. The timing of minima is remarkably consistent from year to year. Long wave propagation modeling is used to show that the location of nightside minima at an altitude of 45–75 km in the subionospheric waveguide represents the location of the sunrise terminator on the great circle path when dayside minima occur. Article in Journal/Newspaper Antarc* Antarctica Natural Environment Research Council: NERC Open Research Archive Faraday ENVELOPE(-64.256,-64.256,-65.246,-65.246) Cutler ENVELOPE(-60.981,-60.981,-62.612,-62.612) Radio Science 34 4 939 948 |
institution |
Open Polar |
collection |
Natural Environment Research Council: NERC Open Research Archive |
op_collection_id |
ftnerc |
language |
unknown |
description |
We present a detailed study of the times of amplitude minima observed on the 12-Mm path from NAA (24 kHz, 1 MW, Cutler, Maine) to Faraday, Antarctica, during the period 1990–1995. (NAA is a naval transmitter call sign.) This study represents the first account of the effect of the sunrise terminator when it is parallel to a propagation path at some times of the year. Since the NAA-Faraday path is within 3° of the north-south meridian, parallel orientation happens close to the equinoxes, while the maximum angle of incidence occurs during the solstices. During the solstices the terminator takes a significant length of time to cross the entire propagation path, so modal conversion effects are observed over a range of hours. During the equinoxes, however, the leading edge of the night-day transition region crosses the whole propagation path within 20 min. The interpretation of the timing of minima is consistent with modal conversion taking place as the sunrise terminator crosses the NAA-Faraday transmission path at specific, consistent locations. The timing of minima is remarkably consistent from year to year. Long wave propagation modeling is used to show that the location of nightside minima at an altitude of 45–75 km in the subionospheric waveguide represents the location of the sunrise terminator on the great circle path when dayside minima occur. |
format |
Article in Journal/Newspaper |
author |
Clilverd, Mark A. Thomson, Neil R. Rodger, Craig J. |
spellingShingle |
Clilverd, Mark A. Thomson, Neil R. Rodger, Craig J. Sunrise effects on VLF signals propagating over a long north-south path |
author_facet |
Clilverd, Mark A. Thomson, Neil R. Rodger, Craig J. |
author_sort |
Clilverd, Mark A. |
title |
Sunrise effects on VLF signals propagating over a long north-south path |
title_short |
Sunrise effects on VLF signals propagating over a long north-south path |
title_full |
Sunrise effects on VLF signals propagating over a long north-south path |
title_fullStr |
Sunrise effects on VLF signals propagating over a long north-south path |
title_full_unstemmed |
Sunrise effects on VLF signals propagating over a long north-south path |
title_sort |
sunrise effects on vlf signals propagating over a long north-south path |
publisher |
American Geophysical Union |
publishDate |
1999 |
url |
http://nora.nerc.ac.uk/id/eprint/503087/ https://doi.org/10.1029/1999RS900052 |
long_lat |
ENVELOPE(-64.256,-64.256,-65.246,-65.246) ENVELOPE(-60.981,-60.981,-62.612,-62.612) |
geographic |
Faraday Cutler |
geographic_facet |
Faraday Cutler |
genre |
Antarc* Antarctica |
genre_facet |
Antarc* Antarctica |
op_relation |
Clilverd, Mark A. orcid:0000-0002-7388-1529 Thomson, Neil R.; Rodger, Craig J. 1999 Sunrise effects on VLF signals propagating over a long north-south path. Radio Science, 34 (4). 939-948. https://doi.org/10.1029/1999RS900052 <https://doi.org/10.1029/1999RS900052> |
op_doi |
https://doi.org/10.1029/1999RS900052 |
container_title |
Radio Science |
container_volume |
34 |
container_issue |
4 |
container_start_page |
939 |
op_container_end_page |
948 |
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1766248676751048704 |