Developing a nowcasting capability for X‐Class solar flares using VLF radiowave propagation changes
A technique for analysing very low frequency (VLF) radiowave signals is investigated in order to achieve rapid, real‐time detection of large solar flares, through the monitoring of changes in VLF radio signal propagation conditions. The reliability of the use of VLF phase and amplitude perturbations...
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American Geophysical Union
2019
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Online Access: | http://nora.nerc.ac.uk/id/eprint/526184/ https://nora.nerc.ac.uk/id/eprint/526184/1/George_et_al-2019-Space_Weather.pdf https://doi.org/10.1029/2019SW002297 |
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ftnerc:oai:nora.nerc.ac.uk:526184 2024-06-02T07:56:03+00:00 Developing a nowcasting capability for X‐Class solar flares using VLF radiowave propagation changes George, Harriet E. Rodger, Craig J. Clilverd, Mark A. Cresswell‐Moorcock, Kathy Brundell, James B. Thomson, Neil R. 2019-12-27 text http://nora.nerc.ac.uk/id/eprint/526184/ https://nora.nerc.ac.uk/id/eprint/526184/1/George_et_al-2019-Space_Weather.pdf https://doi.org/10.1029/2019SW002297 en eng American Geophysical Union https://nora.nerc.ac.uk/id/eprint/526184/1/George_et_al-2019-Space_Weather.pdf George, Harriet E.; Rodger, Craig J.; Clilverd, Mark A. orcid:0000-0002-7388-1529 Cresswell‐Moorcock, Kathy; Brundell, James B.; Thomson, Neil R. 2019 Developing a nowcasting capability for X‐Class solar flares using VLF radiowave propagation changes. Space Weather, 17 (12). 1783-1799. https://doi.org/10.1029/2019SW002297 <https://doi.org/10.1029/2019SW002297> cc_by_4 Publication - Article PeerReviewed 2019 ftnerc https://doi.org/10.1029/2019SW002297 2024-05-07T23:32:29Z A technique for analysing very low frequency (VLF) radiowave signals is investigated in order to achieve rapid, real‐time detection of large solar flares, through the monitoring of changes in VLF radio signal propagation conditions. The reliability of the use of VLF phase and amplitude perturbations to determine the X‐ray fluxes involved during 10 large solar flare events (>X1) is examined. Linear regression analysis of signals from the NPM transmitter in Hawaii, received at Arrival Heights, Scott Base, Antarctica over the years 2011‐2015 shows that VLF phase perturbations during large solar flares have a 1.5‐3 times lower mean square error when modelling the long wavelength X‐ray fluxes than the equivalent short wavelength fluxes. The use of VLF amplitude observations to determine long or short wavelength X‐ray flux levels have a 4‐10 times higher mean square error than when using VLF phase. Normalised linear regression analysis identifies VLF phase as the most important parameter in the regression, followed by solar zenith angle at the mid‐point of the propagation path, then the initial solar X‐ray flux level (from 5 min before the impact of the solar flare), with F10.7 cm flux from the day beforehand providing the least important contribution. Transmitter phase measurements are more difficult to undertake than amplitude. However, networks of VLF receivers already exist which include the high quality phase capability required for such a nowcasting product. Such narrowband VLF data can be a redundant source of flare monitoring if satellite data is not available. Article in Journal/Newspaper Antarc* Antarctica Natural Environment Research Council: NERC Open Research Archive Arrival Heights ENVELOPE(166.650,166.650,-77.817,-77.817) Scott Base ENVELOPE(166.766,166.766,-77.849,-77.849) Space Weather 17 12 1783 1799 |
institution |
Open Polar |
collection |
Natural Environment Research Council: NERC Open Research Archive |
op_collection_id |
ftnerc |
language |
English |
description |
A technique for analysing very low frequency (VLF) radiowave signals is investigated in order to achieve rapid, real‐time detection of large solar flares, through the monitoring of changes in VLF radio signal propagation conditions. The reliability of the use of VLF phase and amplitude perturbations to determine the X‐ray fluxes involved during 10 large solar flare events (>X1) is examined. Linear regression analysis of signals from the NPM transmitter in Hawaii, received at Arrival Heights, Scott Base, Antarctica over the years 2011‐2015 shows that VLF phase perturbations during large solar flares have a 1.5‐3 times lower mean square error when modelling the long wavelength X‐ray fluxes than the equivalent short wavelength fluxes. The use of VLF amplitude observations to determine long or short wavelength X‐ray flux levels have a 4‐10 times higher mean square error than when using VLF phase. Normalised linear regression analysis identifies VLF phase as the most important parameter in the regression, followed by solar zenith angle at the mid‐point of the propagation path, then the initial solar X‐ray flux level (from 5 min before the impact of the solar flare), with F10.7 cm flux from the day beforehand providing the least important contribution. Transmitter phase measurements are more difficult to undertake than amplitude. However, networks of VLF receivers already exist which include the high quality phase capability required for such a nowcasting product. Such narrowband VLF data can be a redundant source of flare monitoring if satellite data is not available. |
format |
Article in Journal/Newspaper |
author |
George, Harriet E. Rodger, Craig J. Clilverd, Mark A. Cresswell‐Moorcock, Kathy Brundell, James B. Thomson, Neil R. |
spellingShingle |
George, Harriet E. Rodger, Craig J. Clilverd, Mark A. Cresswell‐Moorcock, Kathy Brundell, James B. Thomson, Neil R. Developing a nowcasting capability for X‐Class solar flares using VLF radiowave propagation changes |
author_facet |
George, Harriet E. Rodger, Craig J. Clilverd, Mark A. Cresswell‐Moorcock, Kathy Brundell, James B. Thomson, Neil R. |
author_sort |
George, Harriet E. |
title |
Developing a nowcasting capability for X‐Class solar flares using VLF radiowave propagation changes |
title_short |
Developing a nowcasting capability for X‐Class solar flares using VLF radiowave propagation changes |
title_full |
Developing a nowcasting capability for X‐Class solar flares using VLF radiowave propagation changes |
title_fullStr |
Developing a nowcasting capability for X‐Class solar flares using VLF radiowave propagation changes |
title_full_unstemmed |
Developing a nowcasting capability for X‐Class solar flares using VLF radiowave propagation changes |
title_sort |
developing a nowcasting capability for x‐class solar flares using vlf radiowave propagation changes |
publisher |
American Geophysical Union |
publishDate |
2019 |
url |
http://nora.nerc.ac.uk/id/eprint/526184/ https://nora.nerc.ac.uk/id/eprint/526184/1/George_et_al-2019-Space_Weather.pdf https://doi.org/10.1029/2019SW002297 |
long_lat |
ENVELOPE(166.650,166.650,-77.817,-77.817) ENVELOPE(166.766,166.766,-77.849,-77.849) |
geographic |
Arrival Heights Scott Base |
geographic_facet |
Arrival Heights Scott Base |
genre |
Antarc* Antarctica |
genre_facet |
Antarc* Antarctica |
op_relation |
https://nora.nerc.ac.uk/id/eprint/526184/1/George_et_al-2019-Space_Weather.pdf George, Harriet E.; Rodger, Craig J.; Clilverd, Mark A. orcid:0000-0002-7388-1529 Cresswell‐Moorcock, Kathy; Brundell, James B.; Thomson, Neil R. 2019 Developing a nowcasting capability for X‐Class solar flares using VLF radiowave propagation changes. Space Weather, 17 (12). 1783-1799. https://doi.org/10.1029/2019SW002297 <https://doi.org/10.1029/2019SW002297> |
op_rights |
cc_by_4 |
op_doi |
https://doi.org/10.1029/2019SW002297 |
container_title |
Space Weather |
container_volume |
17 |
container_issue |
12 |
container_start_page |
1783 |
op_container_end_page |
1799 |
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1800753028367646720 |