EGU21-14395
https://doi.org/10.5194/egusphere-egu21-14395
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

The quantification and possible sources of spatially structured and large amplitude geomagnetic depressions during strong geomagnetic storms measured by IMAGE

Andrew Dimmock1, Lisa Rosenqvist2, Ari Viljanen3, Colin Forsyth4, Mervyn Freeman5, Jonathan Rae6, and Emiliya Yordanova1
Andrew Dimmock et al.
  • 1Swedish Institute of Space Physics (IRF), Uppsala, Sweden (andrew.dimmock@irfu.se)
  • 2Swedish Defence Research Agency (FOI), Stockholm, Sweden
  • 3Finnish Meteorological Institute (FMI), Helsinki, Finland
  • 4UCL Mullard Space Science Laboratory (MSSL), Dorking, UK
  • 5British Antarctic Survey (BAS), Cambridge, UK
  • 6Northumbria University, Newcastle, UK

Geomagnetically Induced Currents (GICs) are a space weather hazard that can negatively impact large ground-based infrastructures such as power lines, pipelines, and railways. They are driven by the dynamic spatiotemporal behaviour of currents flowing in geospace, which drive rapid geomagnetic disturbances on the ground. In some cases, geomagnetic disturbances are highly localised and spatially structured due to the dynamical behaviour of geospace currents and magnetosphere-ionosphere (M-I) coupling dynamics, which are complex and often unclear.

In this work, we investigate and quantify the spatial structure of large geomagnetic depressions exceeding several hundred nT according to the 10 strongest events measured over Fennoscandia by IMAGE. Using ground magnetometer measurements we connect these spatially structured geomagnetic disturbances to possible M-I coupling processes and identify their likely magnetospheric origin. In addition, the ability for these disturbances to drive large GICs is assessed by calculating their respective geoelectric fields in Sweden using the SMAP ground conductivity model. To compliment the observations, we also utilise high resolution runs (>7 million cells) of the Space Weather Modeling Framework (SWMF) to determine to what extent global MHD models can capture this behaviour.

How to cite: Dimmock, A., Rosenqvist, L., Viljanen, A., Forsyth, C., Freeman, M., Rae, J., and Yordanova, E.: The quantification and possible sources of spatially structured and large amplitude geomagnetic depressions during strong geomagnetic storms measured by IMAGE, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-14395, https://doi.org/10.5194/egusphere-egu21-14395, 2021.

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