For the two Coordinated Data Analysis Workshop 6 intervals, we derived the global distribution above the north polar region of ionospheric currents, field-aligned currents, electric fields and Joule heat from geomagnetic variations recorded at 107 stations and modeled values of ionospheric conductance (Kamide et al., 1983). In addition, we computed several scalar indices which summarize changes in the magnetic and electric fields at high latitudes. Since these indices were derived from the same data, namely ground magnetic variations, a high degree of similarity is expected to exist among their temporal variations, as the correlation coefficients lie between 0.41 and 0.98. From the cross correlation between the total auroral electrojet currents and the AU and AL indices of electrojet current density, we find that the latitudinal width of the westward electrojet expands (contacts) simultaneously with an increase (decrease) in current density. However, the lower correlation between AU and the total eastward current demonstrates the importance of changes of latitudinal width to the total eastward current. The relatively poor correlation between AU and AL highlights the differences between the two indices and raises doubts about the meaning of the AE index, which is a linear combination of the two. We notice that both electric potential and conductivity changes influence the electrojets. When the elextric potential difference across the polar cap is large in relation to a given intensity of the total current, the ''true'' ionospheric current shows a maximum westward electrojet near dawn and a maximum eastward electrojet near dusk. When the two indices are relatively equal, the westward electrojet maximum moves toward midnight while the eastward electrojet stays near dusk.