Diurnal and annual variations in 10-kHz radio noise
It is shown that the investigation of lightning activity levels, using very low frequency radio emissions near 10 kHz, needs to take into account the significant influences of subionospheric propagation. Ten-kilohertz spectral power measurements made at Halley, Antarctica (76°S, 26°W), show at least...
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American Geophysical Union
1999
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ftnerc:oai:nora.nerc.ac.uk:503088 2023-05-15T13:48:07+02:00 Diurnal and annual variations in 10-kHz radio noise Clilverd, Mark A. Watkins, Nicholas W. Smith, Andy J. Yearby, Keith H. 1999 http://nora.nerc.ac.uk/id/eprint/503088/ https://doi.org/10.1029/1999RS900009 unknown American Geophysical Union Clilverd, Mark A. orcid:0000-0002-7388-1529 Watkins, Nicholas W.; Smith, Andy J.; Yearby, Keith H. 1999 Diurnal and annual variations in 10-kHz radio noise. Radio Science, 34 (4). 933-938. https://doi.org/10.1029/1999RS900009 <https://doi.org/10.1029/1999RS900009> Publication - Article PeerReviewed 1999 ftnerc https://doi.org/10.1029/1999RS900009 2023-02-04T19:37:38Z It is shown that the investigation of lightning activity levels, using very low frequency radio emissions near 10 kHz, needs to take into account the significant influences of subionospheric propagation. Ten-kilohertz spectral power measurements made at Halley, Antarctica (76°S, 26°W), show at least two significant periodicities. The largest variation (10 dB) is due to the diurnal cycle and is strongly dominated by South American thunderstorm activity levels. The effect of African thunderstorm activity is observable in the diurnal variation plots but is strongly reduced by disadvantageous propagation conditions. The analysis suggests that given two identical tropical source regions, one situated east and one situated west, of a polar receiver site, the region to the west will tend to dominate the diurnal variation. The smaller annual variation at Halley (3 dB) can be explained by the improved subionospheric propagation conditions during the Southern Hemisphere winter counterbalancing the seasonal effects of decreased source activity in South America. Article in Journal/Newspaper Antarc* Antarctica Natural Environment Research Council: NERC Open Research Archive Radio Science 34 4 933 938 |
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Open Polar |
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Natural Environment Research Council: NERC Open Research Archive |
op_collection_id |
ftnerc |
language |
unknown |
description |
It is shown that the investigation of lightning activity levels, using very low frequency radio emissions near 10 kHz, needs to take into account the significant influences of subionospheric propagation. Ten-kilohertz spectral power measurements made at Halley, Antarctica (76°S, 26°W), show at least two significant periodicities. The largest variation (10 dB) is due to the diurnal cycle and is strongly dominated by South American thunderstorm activity levels. The effect of African thunderstorm activity is observable in the diurnal variation plots but is strongly reduced by disadvantageous propagation conditions. The analysis suggests that given two identical tropical source regions, one situated east and one situated west, of a polar receiver site, the region to the west will tend to dominate the diurnal variation. The smaller annual variation at Halley (3 dB) can be explained by the improved subionospheric propagation conditions during the Southern Hemisphere winter counterbalancing the seasonal effects of decreased source activity in South America. |
format |
Article in Journal/Newspaper |
author |
Clilverd, Mark A. Watkins, Nicholas W. Smith, Andy J. Yearby, Keith H. |
spellingShingle |
Clilverd, Mark A. Watkins, Nicholas W. Smith, Andy J. Yearby, Keith H. Diurnal and annual variations in 10-kHz radio noise |
author_facet |
Clilverd, Mark A. Watkins, Nicholas W. Smith, Andy J. Yearby, Keith H. |
author_sort |
Clilverd, Mark A. |
title |
Diurnal and annual variations in 10-kHz radio noise |
title_short |
Diurnal and annual variations in 10-kHz radio noise |
title_full |
Diurnal and annual variations in 10-kHz radio noise |
title_fullStr |
Diurnal and annual variations in 10-kHz radio noise |
title_full_unstemmed |
Diurnal and annual variations in 10-kHz radio noise |
title_sort |
diurnal and annual variations in 10-khz radio noise |
publisher |
American Geophysical Union |
publishDate |
1999 |
url |
http://nora.nerc.ac.uk/id/eprint/503088/ https://doi.org/10.1029/1999RS900009 |
genre |
Antarc* Antarctica |
genre_facet |
Antarc* Antarctica |
op_relation |
Clilverd, Mark A. orcid:0000-0002-7388-1529 Watkins, Nicholas W.; Smith, Andy J.; Yearby, Keith H. 1999 Diurnal and annual variations in 10-kHz radio noise. Radio Science, 34 (4). 933-938. https://doi.org/10.1029/1999RS900009 <https://doi.org/10.1029/1999RS900009> |
op_doi |
https://doi.org/10.1029/1999RS900009 |
container_title |
Radio Science |
container_volume |
34 |
container_issue |
4 |
container_start_page |
933 |
op_container_end_page |
938 |
_version_ |
1766248676931403776 |