Modelling Electric Fields In Ireland And UK For Space Weather Applications

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1 Modelling Electric Fields In Ireland nd UK For Space Weather pplications Joan Campanyà 1, Peter Gallagher 1, Seán Blake 1, Mark Gibbs 2, David Jackson 2, Ciarán Beggan 3, Gemma S. Richardson 3, Colin Hogg 4 [1] School of Physics, Trinity College Dublin, Dublin, Ireland [2] Met Office, Exeter, UK [3] British Geological Survey, Edinburgh, UK [4] Dublin Institute for dvanced Studies (DIS)

2 Why do we want to model the electric fields? Geomagnetic Induced Currents (GICs) Solar ctivity Solar storms Earth Magnetic Field Variations Induced Electric Fields B(t) field variations Faraday s law Power Transmission Network NS Induced Electric Currents

3 rea of Interest Ireland and UK Permanent Magnetic Observatories Permanent Electric Observatories Temporary site (electrics and magnetics) INTERMGNET & MagIE

4 rea of Interest Ireland and UK?????????????????? Permanent Magnetic Observatories Permanent Electric Observatories Temporary site (electrics and magnetics) How accurate can we model the electric fields at sites with no permanent recordings? INTERMGNET & MagIE

Sources of EM fields Primary Magnetic Field & Influence of the Subsurface Geology Primary magnetic field (Interpolate between Magnetic Observatories) km Influence

5 Sources of EM fields Primary Magnetic Field & Influence of the Subsurface Geology Primary magnetic field (Interpolate between Magnetic Observatories) km Influence of the geology (Magnetotelluric geophysical method: Tensor relationships relating EM fields) [Ω m] Max. distance Ireland: ~ 200km UK: ~500km

6 Sources of EM fields Primary Magnetic Field & Influence of the Subsurface Geology Primary magnetic field (Interpolate between Magnetic Observatories) km Spherical elementary current systems (SECS, ionospheric currents) Linear interpolation Cubic interpolation Max. distance Ireland: ~ 200km UK: ~500km

7 Sources of EM fields Primary Magnetic Field & Influence of the Subsurface Geology Primary magnetic field (Interpolate between Magnetic Observatories) km Spherical elementary current systems (SECS, ionospheric currents) Linear interpolation Cubic interpolation Max. distance Ireland: ~ 200km UK: ~500km Linear and Cubic interpolation are NOT accurate during storms

8 Sources of EM fields Primary Magnetic Field & Influence of the Subsurface Geology Tensor relationships MT Impedance Tensor, Z ( local) (ω): Frequency dependence

9 Sources of EM fields Primary Magnetic Field & Influence of the Subsurface Geology Tensor relationships MT Impedance Tensor, Z ( local) Inter-station Impedance Tensor, Z Inter-station Horizontal Magnetic, M (ω): Frequency dependence

10 Sources of EM fields Primary Magnetic Field & Influence of the Subsurface Geology Tensor relationships MT Impedance Tensor, Z ( local) Inter-station Impedance Tensor, Z Data needs to be measured at least ones at the site of interest to compute the Tensor relationships Works under the Plane-Wave approximation: similar primary magnetic field in both sites Inter-station Horizontal Magnetic, M (ω): Frequency dependence

11 Sources of EM fields Primary Magnetic Field & Influence of the Subsurface Geology Influence of the geology on the magnetic field (Secondary/Induced magnetic field) Tensor Relationship between magnetic fields (assuming same magnetic source for all the sites) Real Imaginary log10 Period (s) log10 Period (s) Site : ESK Site B: HD, ESK, LER, VL, BIR, RM

By (nt) Bx (nt) Sources of EM fields Primary Magnetic Field & Influence of the Subsurface Geology Influence of the geology on the magnetic field (Secondary/Induced magnetic field) Tensor Relationship

12 By (nt) Bx (nt) Sources of EM fields Primary Magnetic Field & Influence of the Subsurface Geology Influence of the geology on the magnetic field (Secondary/Induced magnetic field) Tensor Relationship between magnetic fields (assuming same magnetic source for all the sites) June 2015 storm Real Imaginary log10 Period (s) log10 Period (s) Site : ESK Site B: HD, ESK, LER, VL, BIR, RM Time (minutes)

13 Modelling E fields Testing different approaches Method 1 E T = Z B B as a result of SECS interpolation using measured magnetic fields as inputs

14 Modelling E fields Testing different approaches Method 1 Method 2 E T = Z B B as a result of SECS interpolation using measured magnetic fields as inputs Total = regional + local E T = E reg + E loc

15 Modelling E fields Testing different approaches Method 1 Method 2 regional E T = Z B Total = regional + local E T = E reg E reg = Z Mr B Mr Not account for different magnetic sources (plane wave approx.) B as a result of SECS interpolation using measured magnetic fields as inputs + E loc Mr: Magnetic Reference site, such as CLF (less affected by local storms)

16 Modelling E fields Testing different approaches Method 1 Method 2 regional Total = regional + local E T = Z B E T = E reg + E loc E reg = Z Mr B Mr E loc Not account for different magnetic sources (plane wave approx.) B as a result of SECS interpolation using measured magnetic fields as inputs Mr: Magnetic Reference site, such as CLF (less affected by local storms) = Z B loc Correction for local storms B loc local as a result SECS interpolation using i local magnetic storms as input (B loc for i = VL, BIR, RM, LER, ESK, HD ). i B loc = B i M imr B Mr

17 Modelling E fields Testing different approaches Method 1 Method 2 regional Total = regional + local E T = Z B E T = E reg + E loc E reg = Z Mr B Mr E loc Not account for different magnetic sources (plane wave approx.) B as a result of SECS interpolation using measured magnetic fields as inputs Mr: Magnetic Reference site, such as CLF (less affected by local storms) = Z B loc Correction for local storms B loc local as a result SECS interpolation using i local magnetic storms as input (B loc for i = We aim to reduce the influence of the interpolation methods VL, BIR, RM, LER, ESK, HD ). i B loc = B i M imr B Mr

Modelling E fields 22-23 June 2015 Storm, ESK Observatory Method 1 Method 2 Ex Ey Ex Ey

18 Modelling E fields June 2015 Storm, ESK Observatory Method 1 Method 2 Ex Ey Ex Ey Coherence RMS Pp Coherence RMS Pp

Modelling E fields 22-23 June 2015 Storm, ESK Observatory MT with BESK Method 2 Ex Ey Ex Ey

19 Modelling E fields June 2015 Storm, ESK Observatory MT with BESK Method 2 Ex Ey Ex Ey Coherence RMS Pp Coherence RMS Pp

20 Modelling E fields ESK and LEI sites for two different storms March, 2015 Dist. Method_1 Method_2 Local B Obs. Coh RMS Pp Coh RMS Pp Coh RMS Pp [km] ESK LEI June, 2015 Method_1 Method_2 Local B Coh RMS Pp Coh RMS Pp Coh RMS Pp ESK LEI Coherence (Coh) 0 1 Performance Parameter (Pp) 0 *RM Observatory stop recording Dist. Obs. [km]

21 New EM data Ireland and UK LER VL RM BIR HD ESK New EM Sites Sites already acquired Permanent magnetic observatories

22 Conclusions Modelling electric fields in Ireland and UK New approach for modelling E fields (Method 2) Higher accuracy Differentiate between local and regional signal joan.campanya@tcd.ie

23 Conclusions Modelling electric fields in Ireland and UK New approach for modelling E fields (Method 2) Higher accuracy Differentiate between local and regional signal Constrained levels of accuracy (approx.): Ireland: Coh 0.8; Pp 0.4 UK: Coh 0.65; Pp 0.3 RMS depends on the storm; larger storms larger RMS joan.campanya@tcd.ie

24 Conclusions Modelling electric fields in Ireland and UK New approach for modelling E fields (Method 2) Higher accuracy Differentiate between local and regional signal Constrained levels of accuracy (approx.): Ireland: Coh 0.8; Pp 0.4 UK: Coh 0.65; Pp 0.3 RMS depends on the storm; larger storms larger RMS New EM data in Ireland and UK Modelling EM fields at country scale. joan.campanya@tcd.ie

25 Conclusions Modelling electric fields in Ireland and UK New approach for modelling E fields (Method 2) Higher accuracy Differentiate between local and regional signal Constrained levels of accuracy (approx.): Ireland: Coh 0.8; Pp 0.4 UK: Coh 0.65; Pp 0.3 RMS depends on the storm; larger storms larger RMS New EM data in Ireland and UK Modelling EM fields at country scale. Computational costs Over 7 min with standard PC, mostly to calculate SECS, which is not ideal for monitoring (Machine learning?) joan.campanya@tcd.ie

GIC at mid-latitudes under extreme Dst scenarios

GIC at mid-latitudes under extreme Dst scenarios Gemma Kelly 1, Ari Viljanen 2, Ciaran Beggan 1, Alan Thomson 1, Alexis Ruffenach 3 1 2 3 Introduction Study of GIC in Europe Higher profile of Space Weather