Map plot of the last hour

Auroras are likely to be seen when the circles are red. Magnetic disturbance level at these times exceeds a certain threshold.

map


Comparison studies of the long-term magnetic and auroral data sets of FMI have increased our knowledge about the statistical behaviour of auroras. Especially, the probability to see auroras is known to increase in Southern Finland if the magnetometer at Nurmijärvi records changes larger than 0.3 nT per second calculated from minute values. The corresponding threshold for Sodankylä latitudes is about 5 nT per ten seconds. The circles on the map show the 10 minute maxima changes in the horizontal magnetic field components (in units 0.01 nT/s) recorded at the Nurmijärvi,Hankasalmi, Oulujärvi, Sodankylä, Muonio, Kevo and Kilpisjärvi observatories during the last 24 hours. The magnetically quiet times are marked with blue circles and the disturbed times with red circles. Missing values are marked with black circles. A ten minute period is considered as disturbed if the value in scale of the plot exceeds 30 in Nurmijärvi, 35 in Hankasalmi, 42 in Oulujärvi, 50 in Sodankylä, 52 in Muonio or 57 in Kevo and Kilpisjärvi.

 

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