Images of auroral emissions observed with Dynamics Explorer 1 (DE 1) are used to calculate ionospheric conductivities over the polar region. The combination of ground-based magnetometer data and the inferred conductivities enables us to estimate on a global scale the distributions of ionospheric electric fields and currents and field-aligned currents, as well as the Joule heating production rate, with a time resolution of 12 min. Although our inference of the conductivity distribution requires further improvements, the following conclusions may be drawn from this work: (1) The westward electrojet is, in general, collocated with the region of high auroral luminosity, while the region of relatively low luminosity in the evening sector is collocated with the eastward electrojet. (2) The upward field-aligned currents exist in the brightest auroral region on the poleward side of the evening auroral oval and on the equatorward side of the morning oval.

However, the magnitudes of these upward currents are not in proportion to the auroral luminosities, suggesting that the characteristic energies of precipitating electrons carrying the upward currents and generating the auroral luminosities may be different. (3) A significant amount of ionospheric currents can flow in regions where there are no bright auroral emissions. An example of this effect is found over the poleward half of the westward electrojet in the morning sector, where the electric field is the main contributor to the ionospheric currents. (4) The distribution of calculated field-aligned currents displays many localized structures which characterize the development of the substorm current system. Previous satellite observations may represent gross time averages of such complicated distributions.