Verifying GIC nowcast models with geo-electric field measurements

To understand how space weather impacts the GB power grid, BGS models estimate geomagntically induced currents in the grid, in near real-time. This begins with a model of the surface electric field that rapid geomagnetic variations produce, before using the network topology to determine the size of GICs in the grid. Previously we have had no way of verifying the electric field model as the electric field has not been routinely measured anywhere in the UK. Recently we initiated a project to provide long term measurements of the electric field at three UK geomagnetic observatories. For the first time we are now able to make comparisons between our electric field model and real data. This is already helping us to constrain our electric field models and hence should improve the estimation of induced currents in the GB power system. Here we present early results from this project, including a comparison of measured and modelled data, which will ultimately aid numerical model developments. We also describe the field set up and instrumentation.