Real-Time Space Weather Predictions
Geomagnetic Perturbations at Ground Level

HINT: Make your browser window wider to display maps in two columns; more narrow to show them in one vertical column.

These maps show variations in the magnetic field at the surface of the Earth, due to the effects of currents flowing in the ionosphere above. These are perturbations to the much stronger (about 100x) main field, that is generated inside the Earth. The units are nano-Tesla (nT). The North-South values are positive where the field is directed toward the North pole (and therefore changes sign going across the pole). The Vertical perturbations are positive in the downward direction.

These maps were generated using measurements of the solar wind and Interplanetary Magnetic Field (IMF) that were obtained by the Deep Space Climate Observatory (DSCOVR) satellite. DSCOVR is in a Lissajous orbit at the L1 point. The real-time telemetry data stream is processed and distributed by the NOAA Space Weather Prediction Center.

The prediction is based on 20-minute average values of the IMF and solar wind velocity. The time of the prediction is determined by the time of the most recent measurement, the measured solar wind velocity, the current position of DSCOVR, and the orientation angles of the IMF transitions. The propagation delay between the time of the measurement of the solar wind/IMF with DSCOVR, to the response in the ionosphere, is graphed at the top of "IMF Measurements." The green lines show the delay computed without compensating for the changing orientation angles, and the blue lines show the values that include this calculation. The distance between DSCOVR and the Earth-Sun line also influences this calculation.

Information about the development of this predictive model is contained in these two publications:
Journal of Geophysical Research 2010JA015540.
Space Weather swe.20030
If you cannot access the PDF copies, then send an e-mail to the author for a copy.