U.S. Geological Survey Near Real-Time Dst Index

The operational version of the United States Geological Survey one-minute Dst index (a global geomagnetic disturbance-intensity index for scientific studies and definition of space-weather effects) uses either four- or three-station input (including Honolulu, Hawaii; San Juan, Puerto Rico; Hermanus, South Africa; and Kakioka, Japan; or Honolulu, San Juan and Guam) and a method based on the U.S. Geological Survey definitive Dst index, in which Dst is more rigorously calculated. The method uses a combination of time-domain techniques and frequency-space filtering to produce the disturbance time series at an individual observatory. The operational output is compared to the U.S. Geological Survey one-minute Dst index (definitive version) and to the Kyoto (Japan) Final Dst to show that the U.S. Geological Survey operational output matches both definitive indices well.