RT info:eu-repo/semantics/article
T1 The relevance of local magnetic records when using extreme space weather events as benchmarks
A1 Saiz Villanueva, María Elena
A1 Cid Tortuero, Consuelo
A1 Guerrero Ortega, Antonio
K1 Local magnetic records
K1 H-spikes
K1 Extreme events
K1 Longitudinal asymmetry
K1 Física
K1 Physics
AB Space weather indices introduced for scientific purposes are commonly used to quantifyoperational nowcast of the geospace state during extreme space weather events. Some indices, such asthe Disturbance storm time (Dst) index, have been applied to situations for which they are not originallyintended. This raises a question about suitability as a space weather benchmark. In analysing historicalrecords for different magnetometers at low- and mid-latitude, we find periods with longitudinal asymmetryin magnetic response that suggest important signals from individual magnetometers are being averaged outof the Dst record. This asymmetry develops as a double spike in the H-component: one negative in theobservatories in the day sector and one positive in the observatories in the night sector. These spikesdevelop 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 recordsduring extreme events (Dst   200 nT and AL   2000 nT) in the period 1998-2017 from six magneticobservatories at about 40  magnetic latitude. Moreover, we show that the largest asymmetries take placeduring the early main phase and are recorded in narrow local time sectors. An important outcome of theseresults is that space weather benchmarks should be based on local records instead of the commonly usedglobal indices. This action improves two important aspects of space weather: the assessment of historicalextreme events and that of the needs of users.
PB EDP Sciences
YR 2021
FD 2021-06-08
LK http://hdl.handle.net/10017/50722
UL http://hdl.handle.net/10017/50722
LA eng
NO Ministerio de Economía y Competitividad
DS MINDS@UW
RD 20-abr-2024