TY - CONF

T1 - Temporal, directional, and spatial statistics of extreme dB/dt

AU - Rogers, Neil

AU - Wild, Jim

AU - Eastoe, Emma

N1 - This is a "Quick View" presentation.

PY - 2020/10/19

Y1 - 2020/10/19

N2 - Extreme geomagnetic fluctuations (dB/dt) have previously been modelled from 1-min cadence data. In this talk we show how occurrence rates for large and extreme dB/dt vary are modelled on timescales from 1 s to 60 min for both ramp changes (i.e. the change in B over n minutes) and RMS variations (of 1-min dB over n minutes), and examine their dependence on geomagnetic latitude, local time, and compass direction. For the 1-min dataset, we also summarise (i) new methods to improve return level estimates by combining generalised Pareto distributions from multiple directional sectors, and (ii) an assessment of the spatial coherence of extremes in dB/dt (pairwise extremal dependence between magnetometer sites worldwide).

AB - Extreme geomagnetic fluctuations (dB/dt) have previously been modelled from 1-min cadence data. In this talk we show how occurrence rates for large and extreme dB/dt vary are modelled on timescales from 1 s to 60 min for both ramp changes (i.e. the change in B over n minutes) and RMS variations (of 1-min dB over n minutes), and examine their dependence on geomagnetic latitude, local time, and compass direction. For the 1-min dataset, we also summarise (i) new methods to improve return level estimates by combining generalised Pareto distributions from multiple directional sectors, and (ii) an assessment of the spatial coherence of extremes in dB/dt (pairwise extremal dependence between magnetometer sites worldwide).

KW - Geomagnetically induced currents (GIC)

KW - space weather

KW - Extreme value theory

M3 - Other

T2 - European Space Weather Symposium

Y2 - 2 November 2020 through 6 November 2020

ER -