Developing a Nowcasting Capability for X-Class Solar Flares Using VLF Radiowave Propagation Changes
A technique for analyzing 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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Language: | English |
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John Wiley & Sons, Ltd
2020
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Online Access: | http://hdl.handle.net/10138/311119 |
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ftunivhelsihelda:oai:helda.helsinki.fi:10138/311119 2024-01-07T09:39:40+01:00 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. Particle Physics and Astrophysics Space Physics Research Group Department of Physics 2020-02-05T13:42:02Z 17 application/pdf http://hdl.handle.net/10138/311119 eng eng John Wiley & Sons, Ltd 10.1029/2019SW002297 George , H E , Rodger , C J , Clilverd , M A , Cresswell-Moorcock , K , Brundell , J B & Thomson , N R 2019 , ' Developing a Nowcasting Capability for X-Class Solar Flares Using VLF Radiowave Propagation Changes ' , Space Weather , vol. 17 , no. 12 , pp. 1783-1799 . https://doi.org/10.1029/2019SW002297 15f1742f-a7c1-4abe-89b5-6f4d634e0b07 http://hdl.handle.net/10138/311119 000508826600011 cc_by openAccess info:eu-repo/semantics/openAccess Solar flares VLF propagation nowcasting VLF phase perturbations solar flare alerts D-REGION ENHANCEMENTS IONOSPHERE SIGNALS PHASE 115 Astronomy Space science Article publishedVersion 2020 ftunivhelsihelda 2023-12-14T00:01:48Z A technique for analyzing 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 modeling 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. Normalized linear regression analysis identifies VLF phase as the most important parameter in the regression, followed by solar zenith angle at the midpoint 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. Peer reviewed Article in Journal/Newspaper Antarc* Antarctica HELDA – University of Helsinki Open Repository 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 |
HELDA – University of Helsinki Open Repository |
op_collection_id |
ftunivhelsihelda |
language |
English |
topic |
Solar flares VLF propagation nowcasting VLF phase perturbations solar flare alerts D-REGION ENHANCEMENTS IONOSPHERE SIGNALS PHASE 115 Astronomy Space science |
spellingShingle |
Solar flares VLF propagation nowcasting VLF phase perturbations solar flare alerts D-REGION ENHANCEMENTS IONOSPHERE SIGNALS PHASE 115 Astronomy Space science 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 |
topic_facet |
Solar flares VLF propagation nowcasting VLF phase perturbations solar flare alerts D-REGION ENHANCEMENTS IONOSPHERE SIGNALS PHASE 115 Astronomy Space science |
description |
A technique for analyzing 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 modeling 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. Normalized linear regression analysis identifies VLF phase as the most important parameter in the regression, followed by solar zenith angle at the midpoint 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. Peer reviewed |
author2 |
Particle Physics and Astrophysics Space Physics Research Group Department of Physics |
format |
Article in Journal/Newspaper |
author |
George, Harriet E. Rodger, Craig J. Clilverd, Mark A. Cresswell-Moorcock, Kathy Brundell, James B. Thomson, Neil R. |
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 |
John Wiley & Sons, Ltd |
publishDate |
2020 |
url |
http://hdl.handle.net/10138/311119 |
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 |
10.1029/2019SW002297 George , H E , Rodger , C J , Clilverd , M A , Cresswell-Moorcock , K , Brundell , J B & Thomson , N R 2019 , ' Developing a Nowcasting Capability for X-Class Solar Flares Using VLF Radiowave Propagation Changes ' , Space Weather , vol. 17 , no. 12 , pp. 1783-1799 . https://doi.org/10.1029/2019SW002297 15f1742f-a7c1-4abe-89b5-6f4d634e0b07 http://hdl.handle.net/10138/311119 000508826600011 |
op_rights |
cc_by openAccess info:eu-repo/semantics/openAccess |
container_title |
Space Weather |
container_volume |
17 |
container_issue |
12 |
container_start_page |
1783 |
op_container_end_page |
1799 |
_version_ |
1787429886861770752 |