Historical dataset of reprocessed AuroraWatch UK activity values. Activity data are provided by a range of magnetometers using a data selection criteria described in the AuroraWatch UK paper. The latest alert alogrithm (at date of production) has been applied to all historical magnetometer data to provide consisten activity values.

The data are formatted into the following columns:
Year (yyyy), Month (mm), Day (dd), Hour (hh), Activity (aa.aa), Site name (xxxx)
Timestamp is in UTC and activity is in nT.