The relevance of local magnetic records when using extreme space weather events as benchmarks

Space weather indices introduced for scientific purposes are commonly used to quantify operational nowcast of the geospace state during extreme space weather events. Some indices, such as the Disturbance storm time (Dst) index, have been applied to situations for which they are not originally intend...

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Main Authors: Saiz Elena, Cid Consuelo, Guerrero Antonio
Format: Article
Language:English
Published: EDP Sciences 2021-01-01
Series:Journal of Space Weather and Space Climate
Subjects:
Online Access:https://www.swsc-journal.org/articles/swsc/full_html/2021/01/swsc200104/swsc200104.html
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author Saiz Elena
Cid Consuelo
Guerrero Antonio
author_facet Saiz Elena
Cid Consuelo
Guerrero Antonio
author_sort Saiz Elena
collection DOAJ
description Space weather indices introduced for scientific purposes are commonly used to quantify operational nowcast of the geospace state during extreme space weather events. Some indices, such as the Disturbance storm time (Dst) index, have been applied to situations for which they are not originally intended. This raises a question about suitability as a space weather benchmark. In analysing historical records for different magnetometers at low- and mid-latitude, we find periods with longitudinal asymmetry in magnetic response that suggest important signals from individual magnetometers are being averaged out of the Dst record. This asymmetry develops as a double spike in the H-component: one negative in the observatories in the day sector and one positive in the observatories in the night sector. These spikes develop in short-time (about 2 h) and pose a potential hazardous effect for users affected by space weather. The results from historical events have been reinforced with the systematic study of magnetic records during extreme events (Dst ≤ −200 nT and AL ≤ −2000 nT) in the period 1998–2017 from six magnetic observatories at about 40° magnetic latitude. Moreover, we show that the largest asymmetries take place during the early main phase and are recorded in narrow local time sectors. An important outcome of these results is that space weather benchmarks should be based on local records instead of the commonly used global indices. This action improves two important aspects of space weather: the assessment of historical extreme events and that of the needs of users.
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spelling doaj.art-1c38f2a852704953852789d4a4f3f2362022-12-21T19:20:53ZengEDP SciencesJournal of Space Weather and Space Climate2115-72512021-01-01113510.1051/swsc/2021018swsc200104The relevance of local magnetic records when using extreme space weather events as benchmarksSaiz Elenahttps://orcid.org/0000-0001-7878-9476Cid Consuelohttps://orcid.org/0000-0002-2863-3745Guerrero Antoniohttps://orcid.org/0000-0002-7056-7753Space weather indices introduced for scientific purposes are commonly used to quantify operational nowcast of the geospace state during extreme space weather events. Some indices, such as the Disturbance storm time (Dst) index, have been applied to situations for which they are not originally intended. This raises a question about suitability as a space weather benchmark. In analysing historical records for different magnetometers at low- and mid-latitude, we find periods with longitudinal asymmetry in magnetic response that suggest important signals from individual magnetometers are being averaged out of the Dst record. This asymmetry develops as a double spike in the H-component: one negative in the observatories in the day sector and one positive in the observatories in the night sector. These spikes develop in short-time (about 2 h) and pose a potential hazardous effect for users affected by space weather. The results from historical events have been reinforced with the systematic study of magnetic records during extreme events (Dst ≤ −200 nT and AL ≤ −2000 nT) in the period 1998–2017 from six magnetic observatories at about 40° magnetic latitude. Moreover, we show that the largest asymmetries take place during the early main phase and are recorded in narrow local time sectors. An important outcome of these results is that space weather benchmarks should be based on local records instead of the commonly used global indices. This action improves two important aspects of space weather: the assessment of historical extreme events and that of the needs of users.https://www.swsc-journal.org/articles/swsc/full_html/2021/01/swsc200104/swsc200104.htmllocal magnetic recordsh-spikesextreme eventslongitudinal asymmetry
spellingShingle Saiz Elena
Cid Consuelo
Guerrero Antonio
The relevance of local magnetic records when using extreme space weather events as benchmarks
Journal of Space Weather and Space Climate
local magnetic records
h-spikes
extreme events
longitudinal asymmetry
title The relevance of local magnetic records when using extreme space weather events as benchmarks
title_full The relevance of local magnetic records when using extreme space weather events as benchmarks
title_fullStr The relevance of local magnetic records when using extreme space weather events as benchmarks
title_full_unstemmed The relevance of local magnetic records when using extreme space weather events as benchmarks
title_short The relevance of local magnetic records when using extreme space weather events as benchmarks
title_sort relevance of local magnetic records when using extreme space weather events as benchmarks
topic local magnetic records
h-spikes
extreme events
longitudinal asymmetry
url https://www.swsc-journal.org/articles/swsc/full_html/2021/01/swsc200104/swsc200104.html
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AT cidconsuelo relevanceoflocalmagneticrecordswhenusingextremespaceweathereventsasbenchmarks
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