Qualitative comparison of ACE/EPAM data from different detector heads: Implications for NOAA RTSW users

The NOAA space environment center (SEC) facilitates the tracking and near real-time data distribution of interplanetary magnetic field, solar wind, and energetic particle observations from the advanced composition explorer near the Earth's first Lagrangian point. In early 2004, the SEC switched from one set of low energy ion observations to another of a similar energy range. To assist users who now must rely upon a different set of observations, this manuscript documents the similarities and differences between the two sets of data. Although the two sets of observations are very similar most of the time, there are occasionally significant differences that users need to be aware of and must account for, especially those using data for operational purposes.