GIC recordings in the Finnish natural gas pipeline - final data

Recordings of GIC are carried out at the Mäntsälä compressor station in southern Finland.

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Top panel: GIC at Mäntsälä as 10-s values. The positive direction of the current is eastward.

Bottom panel: Time derivative of the geographic north component of the magnetic field at the Nurmijärvi Geophysical Observatory (about 40 kilometers westwards from Mäntsälä). -dX/dt correspond quite accurately the east component of the geoelectric field and thus GIC at Mäntsälä follows quite well -dX/dt.

Note: There is occasional noise in the GIC recording, which may be quite prominent when the current is only of the order of one ampere or less. There are also some single error spikes, which we have not removed from the data. A possible linear trend is subtracted from the daily GIC data. We have also applied the Savitzky-Golay filter to improve the quality. Such data plots have the vertical axis label "GIC [A] (filtered)".

Plots are only for quick-look purposes. Before presenting the data anywhere and for a proper interpretation, contact Ari Viljanen (ari.viljanen(at)

GIC recordings are maintained by the Finnish Meteorological Institute, supported by Gasum Oy until December 2010. In March 2011 to February 2014, maintenance of recordings received funding from the European Community's Seventh Framework Programme (FP7/2007-2013) under grant agreement no 260330 (EURISGIC).

Updated: 25 Jan 2017