Post on 29-Jan-2016
Nov 17, 2005, ESWW 2005, Nov 17, 2005, ESWW 2005, Noordwijk, The NetherlandsNoordwijk, The Netherlands
Spatiotemporal properties of dB/dt: setting limits for
the highest achievable accuracy of GIC forecasts
Pulkkinen A., A. Klimas, and D. VassiliadisNASA Goddard Space Flight Center, USA
Nov 17, 2005, ESWW 2005, Nov 17, 2005, ESWW 2005, Noordwijk, The NetherlandsNoordwijk, The Netherlands
Contents
• The ground effects of space weather: the physical quantities of interest
• The event-based view to the dynamics of dB/dt (actually, the geoelectric field)
• The statistical view to the dynamics of dB/dt
• Summary and discussion
Nov 17, 2005, ESWW 2005, Nov 17, 2005, ESWW 2005, Noordwijk, The NetherlandsNoordwijk, The Netherlands
The ground effects of space weather
Energy
Dynamic variationsof the electric currents
BIMFmagnetopauseBIMFmagnetopause
Nov 17, 2005, ESWW 2005, Nov 17, 2005, ESWW 2005, Noordwijk, The NetherlandsNoordwijk, The Netherlands
The ground effects of space weather
GIC
Induction
Spatiotemporal characteristics?
E B
t
Nov 17, 2005, ESWW 2005, Nov 17, 2005, ESWW 2005, Noordwijk, The NetherlandsNoordwijk, The Netherlands
The event-based view
• October 29-31, 2003 geomagnetic storm• Blackout in Malmö, southern Sweden• Details can be found from Pulkkinen, A., S.
Lindahl, A. Viljanen, R. Pirjola, “October 29-31, 2003 geomagnetic storm: geomagnetically induced currents and their relation to problems in the Swedish high-voltage power transmission system”, AGU Space Weather, 2005.
120
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W
60oW
0
o
60
o
E
120oE 1
80
o W
50
o N
60
o N
70
o N
80
o N
25
o W
0
o
25
o
E
50
o
E
75 o E
54 o N
60 o N
66 o N
72
o
N
78 o N
Malmö
Nov 17, 2005, ESWW 2005, Nov 17, 2005, ESWW 2005, Noordwijk, The NetherlandsNoordwijk, The Netherlands
Oct 29, 2003
High-pass filtering
Region of the highest activity
Failures in the Swedish system
Nov 17, 2005, ESWW 2005, Nov 17, 2005, ESWW 2005, Noordwijk, The NetherlandsNoordwijk, The Netherlands
Equivalent currents and E, Oct 30
Oct 30, 2003
Time of the blackout (20:07 UT)
Nov 17, 2005, ESWW 2005, Nov 17, 2005, ESWW 2005, Noordwijk, The NetherlandsNoordwijk, The Netherlands
The event-based view (summary)
“GIC view”
Nov 17, 2005, ESWW 2005, Nov 17, 2005, ESWW 2005, Noordwijk, The NetherlandsNoordwijk, The Netherlands
The statistical view
• Quantify the complexity of the spatiotemporal behavior
• Structure function analysis of the IMAGE magnetometer array data (years 2002-2003)
• • White noise (no predictability):
S2(r,) a(t,r) a(t ,r r)2
S() c
Nov 17, 2005, ESWW 2005, Nov 17, 2005, ESWW 2005, Noordwijk, The NetherlandsNoordwijk, The Netherlands
The statistical view
†
S()
Correlated signal
Break (change in the dynamics)
Disappearance of correlations (or saturation of )
S()
Nov 17, 2005, ESWW 2005, Nov 17, 2005, ESWW 2005, Noordwijk, The NetherlandsNoordwijk, The Netherlands
The statistical view
• Details can be found from Pulkkinen, A., A. Klimas, D. Vassiliadis, V. Uritsky, and E. Tanskanen, “Spatiotemporal scaling properties of the ground geomagnetic field variations”, submitted to J. Geophys. Res., 2005.
Nov 17, 2005, ESWW 2005, Nov 17, 2005, ESWW 2005, Noordwijk, The NetherlandsNoordwijk, The Netherlands
The statistical view (dB/dt)
}
}
Substorms
after continuation to the ionosphere
S(r) c
S() cBreak in 80 - 100 s
dX/dt
dX/dt
dY/dt
dY/dt
Scaling behavior same for substorms and the entire data set
Nov 17, 2005, ESWW 2005, Nov 17, 2005, ESWW 2005, Noordwijk, The NetherlandsNoordwijk, The Netherlands
The statistical view (dB/dt)
• Conditional probability P(dIE|IE)
Local variant of AE
max(dBx
i
dt,dBy
i
dt)
Nov 17, 2005, ESWW 2005, Nov 17, 2005, ESWW 2005, Noordwijk, The NetherlandsNoordwijk, The Netherlands
The statistical view (dB/dt)
• Details can be found from Pulkkinen, A., R. Pirjola, and A. Viljanen, “Estimation of geomagnetically induced current levels from different input data”, to be submitted to AGU Space Weather, 2005.
Nov 17, 2005, ESWW 2005, Nov 17, 2005, ESWW 2005, Noordwijk, The NetherlandsNoordwijk, The Netherlands
The statistical view (dB/dt)
IE = 150, 450, 750, 1050, 1350 nT
Statistics for different geomagnetic environments
Nov 17, 2005, ESWW 2005, Nov 17, 2005, ESWW 2005, Noordwijk, The NetherlandsNoordwijk, The Netherlands
The statistical view (dB/dt)
• Above scales of 80-100 s, dB/dt is essentially white noise both in spatial and temporal sense (substorms and all data)!
• It may not be possible to predict the behavior of dB/dt (phase and amplitude) deterministically
Nov 17, 2005, ESWW 2005, Nov 17, 2005, ESWW 2005, Noordwijk, The NetherlandsNoordwijk, The Netherlands
The statistical view (dB/dt)
• The amplitude of dB/dt fluctuations is modulated by the overall geomagnetic activity (seen also in the Oct 2003 example)
• It may be possible to estimate the likelihood of large dB/dt based on the estimates of the “background” geomagnetic activity
Nov 17, 2005, ESWW 2005, Nov 17, 2005, ESWW 2005, Noordwijk, The NetherlandsNoordwijk, The Netherlands
Summary and discussion
• The complexity of the spatiotemporal variations in the magnetosphere reflected also in the variation of auroral ionospheric currents, as anticipated
• Due to the stochastic nature of the phenomenon, deterministic forecasting of GIC may not be possible
Nov 17, 2005, ESWW 2005, Nov 17, 2005, ESWW 2005, Noordwijk, The NetherlandsNoordwijk, The Netherlands
Summary and discussion
• Statistical approach for GIC forecasts likely needed
• Example: Estimate the approximate location and time of intensification of large-scale convection-related ionospheric currents statistical estimate of GIC levels based on the estimate of the intensity of the currents
Nov 17, 2005, ESWW 2005, Nov 17, 2005, ESWW 2005, Noordwijk, The NetherlandsNoordwijk, The Netherlands
Summary and discussion
Understanding GIC behavior requires “high resolution”
understanding of the solar wind-magnetosphere-ionosphere
system