Estimating ionospheric currents by inversion from ground-based geomagnetic data and calculating geoelectric fields for studies of geomagnetically induced currents

Earth, Planets and Space

Table 2 Parameters of a combined 1D model of the ground conductivity structure

Layers	Depth (km)	Conductivity (mS/m)	Place
Layer 1	0.1	20.00	Addis Ababa, Ethiopia
Layer 2	8.0	0.02
Layer 3	31.0	5.00
Layer 4	100.0	10.00
Layer 5	600.0	1.0	Global (Swarm)
Layer 6	900.0	5.2
Layer 7	1250.0	2700
Layer 8	∞	3750

The model is based on magnetotelluric measurements (adapted from Alekseev et al. 2015 to four layers) and satellite measurements (adapted from Civet et al. 2015 to four layers)