Data Summary
Preliminary and Definitive Data Types
Preliminary Data are unprocessed. They have not been explicitly adjusted for long-term baseline drift, and they have not been cleaned of occasional spikes and step offsets. Preliminary data are reasonably good representations of field variation occurring over time scales shorter than a few days. These data are available on the Real-Time Data Display and in the Blended Real-Time Data. They can also be download form the Real-Time Field & Indices.
Definitive Data are fully processed, they have been adjusted for baseline drift, and they can, therefore, be considered to be absolute. They have also been cleaned for spikes, and step offsets as well as other artifacts and contamination. Insofar as they better represent the actual time-dependent behavior of the Earth's magnetic field, definitive data are superior to preliminary data. Definitive data can be used for either short-term or long-term studies of the geomagnetic field. But since producing definitive data requires the careful inspection of the data and the application of specialized software, they are not made available until some time after their initial collection. More information about definitive data is available on the Historical Field & Indices page.
Flux-gate Magnetometer Data (H,D,Z) Specifications
| Magnetic resolution |
0.1 nT |
| Temporal resolution |
1-minute, 0.1667 Hz |
| Filter type |
Gaussian, using 91 1-second samples |
| Time stamp |
Universal time, filter-centered |
| Preliminary-data availability |
Near-real time, 12-24 minute delay |
| Definitive-data accuracy |
5 nT |
Proton Magnetometer Data (F) Specifications
| Magnetic resolution |
0.1 nT |
| Temporal resolution |
1-minute, 0.1667 Hz |
| Filter type |
Boxcar, using 3 20-second samples |
| Time stamp |
Universal time, filter-centered |
| Preliminary-data availability |
Near-real time, 12-24 minute delay |
| Definitive-data accuracy |
1 nT |
