抄録
The computation of the total eastward and westward auroral electrojets from numerical modeling techniques for three different intervals during disturbed conditions provides a unique opportunity to evaluate the accuracy of the standard Auroral Electrojet indices AU(12) and AL(12). The effect on the indices of replacing the local magnetic coordinate system with a global system, of increasing the latitudinal coverage by increasing the number of stations from 12 to 57, and of integrating the current density to obtain the total current is considered as new indices are correlated with the standard ones. We conclude that AL(12) is a reasonable measure of the westward electrojet current in a statistical sense, that AU(12) is not as good a measure of the eastward current, and that values of AU(12) and AL(12) during quiet conditions, i.e., less than 50nT, must be treated separately from disturbed conditions. It should also be noted that a rotation of the perturbation vectors into a global coordinate system improves the indices more than an increase in the number of stations.
