Recordings of GIC are carried out close to the Mäntsälä compressor station in southern Finland (60.6 N, 25.2 E). Final data are available here as ASCII files. The list below gives links to zip files containing daily files of each year. Each data files has header lines explaining the format.
Some guidelines for using these GIC data:
- We have not checked every data point. There are error spikes and other low-quality features.
- There are long gaps due to occasional instrumental problems.
- The daily average of GIC should be very close to zero. We recommend to subtract a possible linear trend in daily data.
- The configuration of the natural gas pipeline has gradually changed during years with longer sections and new branches. This has some effect on GIC amplitudes, so the time series is not uniform.
- There was also a small shift of the measurement site in May 2005 (see Viljanen et al., 2010: https://www.geophysica.fi/pdf/geophysica_2010_46_1-2_059_viljanen.pdf).
- Data has the best quality in 1999 to April 2005.
- We strongly recommend to compare GIC to dB/dt at the closest geomagnetic observatory at Nurmijärvi (IMAGE magnetometer data). Large GIC values without (nearly) simultaneous large dB/dt are very probably erroneous.
- "Clean" GIC (proxy) values could be obtained by modelling based on magnetic field data of Nurmijärvi (for example, Viljanen et al., 2006: doi:10.1029/ 2006SW000234). This is presently under consideration at FMI.
Note: Recordings were stopped on 23 Oct 2023.
For plots, references and acknowledgements, see
License: CC BY 4.0
Updated: 1 Nov 2023