The Disturbance Storm Time (Dst) index is a measure of geomagnetic activity used to assess the severity of geomagnetic storms. It is expressed in nanoTeslas and is based on the average value of the horizontal component of the Earth's magnetic field measured at four near-equatorial geomagnetic observatories. It measures the growth and recovery of the ring current in the Earth's magnetosphere. The lower these values get, the more energy is stored in Earth's magnetosphere.
This magnetogram gives you the values measured by the ground station of Kiruna (Sweden, Europa). For European middle latitude auroral activity the deflection in the magnetometer data should be more than 1300nT. If you are not located in Europe, please consult a magnetometer near your location for a more accurate representation of the current geomagnetic activity.
This plot shows several magnetometers that are located in Norway, Denmark and Finland, ranked according to their latitude. When a geomagnetic disturbance starts the most northern magnetometers will respond and as the disturbance strengthens the lower magnetometers will respond as well. Once the stations Dombås (DOB) and Solund (SOL) react, there will be a chance for the European middle latitudes to see aurora low at the northern horizon.
Data from Tromsø Geophysical Observatory (TGO), DTU Space (Technical University of Denmark) and Finnish Meteorological Institute (FMI).
This plot shows the 1-minute averaged parallel component of the magnetic field in nanoTeslas, measured by the GOES satellites. A daily variation is observed in these data because at geosynchronous orbit, the magnetic field is stronger on the dayside of Earth and weaker on the nightside. If the data drops below zero when the satellite is on the dayside, it may be due to a compression of the Earth’s magnetopause into the geosynchronous orbit boundaries. On the nightside, the smaller field values indicate strong currents in the magnetotail that are often associated with the stretching and subsequent release of energy in Earths tail which result in aurora on Earth. Noon and midnight local time are plotted as N and M.
Credit: NOAA SWPC.
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