Space Weather Applications
Real-time space weather applications use USGS and international ground-based magnetic field data to provide a derived product. Operational applications undergo a formal transitions procedure and processes are hosted in a operationally-robust and monitored system.
The USGS-Dst index is a global measure of low-latitude magnetic disturbance. It is used to define the phases of a geomagnetic storm. It is provided at a 1-minute time resolution in real-time and supports the operations of NOAA-Space Weather Prediction Center and the Air Force Research Lab.Real-time Dst
The AE index is a global measure of high latitude disturbance due to enhancements of the auroral electrojet. Similar to the Dst index, but using an envelope method instead of averaging, the traditional index uses local disturbance values at a ring of 12 high latitude stations. An updated version, using 40 mid- to high-latitude stations, gives a more complete picture of high latitude disturbance.AE Index (beta)
The K index is a characterization of local disturbance on a 0 to 9 scale. Because disturbance values are larger at higher latitudes, the scale is individually determined for each location to produce similar K values at all locations during geomagnetic disturbance. K values of 0 to 3, 4 to 6, and 7 to 9 are considered low, moderate, and high disturbance, respectively.K Index (beta)
Local Disturbance (Dist) and Solar-Quiet (SQ) Variation
Local Dist values are physical measures (in nT) of the portion of measured magnetic field that is due to external variations, such as geomagnetic storms. The SQ variation is the remaining variation due to ionospheric and internal contributions. In the Dst calculation, some of these Dist values are averaged to produce a global index. The local version may be quite different from the global index if the external disturbance is very asymmetric.Local Disturbance (beta)
Electric Field Estimates
Combining magnetic field measurements with local conductivity values, we estimate the electric field induced by rapid magnetic field changes. Using regional conductivity estimates, we are developing hazard maps based on these electric field calculations that indicate the threat of geomagnetically-induced currents.
Using wavelet analysis to separate by frequency band, the pulsation indices are real-time specifications of Pc3, Pc4, and Pc5 waves. These indices require 1 second data to fully resolve the high frequency components.
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