The Extreme Space Weather Event in February/March 1941
| dc.contributor.author | Hayakawa, Hisashi | |
| dc.contributor.author | Blake, Sean P. | |
| dc.contributor.author | Bhaskar, Ankush | |
| dc.contributor.author | Hattori, Kentaro | |
| dc.contributor.author | Oliveira, Denny M. | |
| dc.contributor.author | Ebihara, Yusuke | |
| dc.date.accessioned | 2020-11-18T19:52:38Z | |
| dc.date.available | 2020-11-18T19:52:38Z | |
| dc.date.issued | 2020-10-01 | |
| dc.description.abstract | Given the infrequency of extreme geomagnetic storms, it is significant to note the concentration of three extreme geomagnetic storms in 1941, whose intensities ranked fourth, twelfth, and fifth within the aa index between 1868-2010. Among them, the geomagnetic storm on 1 March 1941 was so intense that three of the four Dst station magnetograms went off scale. Herein, we reconstruct its time series and measure the storm intensity with an alternative Dst estimate (Dst*). The source solar eruption at 09:29 - 09:38 GMT on 28 February was located at RGO AR 13814 and its significant intensity is confirmed by large magnetic crochets of 35 nT measured at Abinger. This solar eruption most likely released a fast interplanetary coronal mass ejection with estimated speed 2260 km/s. After its impact at 03:57 - 03:59 GMT on 1 March, an extreme magnetic storm was recorded worldwide. Comparative analyses on the contemporary magnetograms show the storm peak intensity of minimum Dst* < -464 nT at 16 GMT, comparable to the most and the second most extreme magnetic storms within the standard Dst index since 1957. This storm triggered significant low-latitude aurorae in the East Asian sector and their equatorward boundary has been reconstructed as 38.5° in invariant latitude. This result agrees with British magnetograms which indicate auroral oval moving above Abinger at 53.0° in magnetic latitude. The storm amplitude was even more enhanced in equatorial stations and consequently casts caveats on their usage for measurements of the storm intensity in Dst estimates. | en_US |
| dc.description.sponsorship | This work was supported in part by JSPS Grant-in-Aids JP15H05812 and JP17J06954, JSPS Overseas Challenge Program for Young Researchers, the 2020 YLC collaborating research fund, and the research grants for Mission Research on Sustainable Humanosphere from Research Institute for Sustainable Humanosphere (RISH) of Kyoto University and Young Leader Cultivation (YLC) program of Nagoya University. We thank Mt. Wilson Observatory for providing sunspot drawings on 27 February 1941, WDC for Geomagnetism at Edinburgh for providing geomagnetic baselines and British magnetograms, WDC for Geomagnetism at Kyoto for providing the Dst index and magnetic measurements at Hermanus, San Juan, Honolulu, and Watheroo, Kakioka Event Database for providing data on the SSC and magnetic storms observed in the said observatory, WDC SILSO for providing international sunspot numbers, and Solar Science Observatory of the NAOJ for providing copies of Quarterly Bulletin on Solar Activity. Magnetograms were digitised using the WebPlotDigitizer software (https://automeris.io/WebPlotDigitizer/). SPB was supported by the NASA’s Living With a Star program (17-LWS17_2-0042). HH thanks Margaret A. Shea for her helpful advices on the historical solar proton events. | en_US |
| dc.description.uri | https://arxiv.org/abs/2010.00452 | en_US |
| dc.format.extent | 24 pages | en_US |
| dc.genre | journal articles preprints | en_US |
| dc.identifier | doi:10.13016/m2dnuz-tpfy | |
| dc.identifier.citation | Hayakawa, Hisashi; Blake, Sean P.; Bhaskar, Ankush; Hattori, Kentaro; Oliveira, Denny M.; Ebihara, Yusuke; The Extreme Space Weather Event in February/March 1941; Space Physics (2020); https://arxiv.org/abs/2010.00452 | en_US |
| dc.identifier.uri | http://hdl.handle.net/11603/20090 | |
| dc.language.iso | en_US | en_US |
| dc.relation.isAvailableAt | The University of Maryland, Baltimore County (UMBC) | |
| dc.relation.ispartof | UMBC Goddard Planetary Heliophysics Institute (GPHI) | |
| dc.relation.ispartof | UMBC Faculty Collection | |
| dc.rights | This item is likely protected under Title 17 of the U.S. Copyright Law. Unless on a Creative Commons license, for uses protected by Copyright Law, contact the copyright holder or the author. | |
| dc.rights | Public Domain Mark 1.0 | * |
| dc.rights | This work was written as part of one of the author's official duties as an Employee of the United States Government and is therefore a work of the United States Government. In accordance with 17 U.S.C. 105, no copyright protection is available for such works under U.S. Law. | |
| dc.rights.uri | http://creativecommons.org/publicdomain/mark/1.0/ | * |
| dc.title | The Extreme Space Weather Event in February/March 1941 | en_US |
| dc.type | Text | en_US |