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Auroral Electrojet Index Designed to Provide a Global Measure, l-minute Intervals, of Auroral Zone Magnetic Activity
The Auroral Electrojet index (AE) is designed to provide a global quantitative measure of auroral zone magnetic activity produced by enhanced ionospheric currents flowing below and within the auroral oval. Ideally, it is the total range of deviation at an instant of time from quiet day values of the horizontal magnetic field (H) around the auroral oval. These indices are computed from a network of geomagnetic observations, some recording digitally and others as analog, which encircle the northern auroral zone. The AE computation uses horizontal magnetic field measured at 1-minute intervals. AE plus the supplemental indices AL, AU, and AO are contained in this data file. For earlier years, the AE indices were derived at 2.5 minutes. Also, hourly mean indices are calculated.