A movie of GIC-index maps (above) for the previous UT day is available by clicking the link Daily Movie. The movie file may take a few seconds to load.

Geomagnetically Induced Currents (GICs) flow in long grounded conductors such as power grids and pipelines as a result of potential differences established by the "geoelectric" field and the associated time varying "geomagnetic" field. The maps are contoured "GIC-index" which is a proxy for the "geoelectric" field in addition to a vector indicating the direction of this field which scales with field amplitude. For low levels of GIC-index activity the vectors appear as dots and increase in size to be visible as directional arrows when activity increases. The index thresholds for these maps were calibrated from reports of GIC impacts from power networks around the world as described in the reference [Marshall et al. 2011] below. It is typically only severe space weather events that will produce GIC-index values with colours other than green for most of the Australian region. The actual physical impact to a power system is complex and requires further interpretation not available at this time, however, GIC-indices show good correlation with measurements of GICs taken within power systems as described in the references below. Procedures for managing the risk to the Australian power network from severe space weather events are now publicly available under the Australian Energy Market Operator website (www.aemo.com.au). Time series plots of GIC-indices from individual magnetometer stations contributing to these maps may be obtained on request to ASWFC@bom.gov.au. Data for these maps are determined by automated algorithms and have not been validated. For further information on the GIC-index and its derivation please refer to the following publications:

Marshall, R. A., C. L. Waters, and M. D. Sciffer (2010), Spectral analysis of pipe-to-soil potentials with variations of the Earth's magnetic field in the Australian region, Space Weather, 8, S05002, doi:10.1029/2009SW000553.

Marshall, R. A., E. A. Smith, M. J. Francis, C. L. Waters, and M. D. Sciffer (2011), A preliminary risk assessment of the Australian region power network to space weather, Space Weather, 9, S10004, doi:10.1029/2011SW000685.

Marshall, R. A., M. Dalzell, C. L. Waters, P. Goldthorpe, and E. A. Smith (2012), Geomagnetically induced currents in the New Zealand power network, Space Weather, 10, S08003, doi:10.1029/2012SW000806.

Marshall, R. A., H. Gorniak, T. van der Walt, C. L. Waters, M. D. Sciffer, M. Miller, M. Dalzell, T. Daly, G. Pouferis, G. Hesse, and P. J. Wilkinson (2013), Observations of geomagnetically induced currents in the Australian Power Network, Space Weather, 11, doi:10.1029/2012SW000849.

Marshall, R. A., Kelly, A., Van Der Walt, T., Honecker, A., Ong, C., Mikkelsen, D., Spierings, A., Ivanovich, G., and Yoshikawa, A. (2017), Modeling geomagnetic induced currents in Australian power networks, Space Weather, 15(7), doi.org/10.1002/2017SW001613.

Marshall, R. A., Wang, L., Paskos, G. A., Olivares‐Pulido, G., Van Der Walt, T., Ong, C., Mikkelsen, D., Hesse, G., McMahon, B., Van Wyk, E., Ivanovich, G., Spoor, D., Taylor, C., and Yoshikawa, A. (2019), Modeling Geomagnetically Induced Currents in Australian Power Networks Using Different Conductivity Models, Space Weather, 17(5), doi.org/10.1029/2018SW002047.

Marshall, R., Dziura, L., Wang, L., Young, J., and Terkildsen, M. (2020), Estimating Extreme Geoelectric Field Values for the Australian Region, Space Weather, 18(11), doi.org/10.1029/2020SW002512.

Marshall, R. A., Pearce, E. A., Waters, C. L., and Terkildsen, M. (2022), Forecasting GIC Activity Associated With Solar Wind Shocks for the Australian Region Power Network, Space Weather, 20(11), doi.org/10.1029/2021sw003029.