Profiles of the surface electric and magnetic fields along longitude 23° East (see Fig. 2) for a simple 1D electrojet model. Top panel shows the vertical magnetic field, middle panel the horizontal (North component) magnetic field and bottom panel the horizontal (East component) electric field. The model distribution is plotted with solid line, and the results calculated using IMAGE and BEAR stations (see Fig. 2) with dash-dotted and dashed lines, respectively.