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Swiss Automatic Magnetic Observatory Station

A permanent Automatic Magnetic Observatory Station (AMOS) delivers values for the earth magnetic field at one-minute intervals. The station is located at 47° 04' N and 7° 02' E (exact location on request) in a forest estate in the Canton of Neuchâtel. A triaxial suspended fluxgate magnetometer (type FGE, Danish Meteorological Institute, Fig. 1) is installed under a one-metre high aluminium dome with tight temperature control (0.1°C, Fig. 2). The X, Y and Z components of the magnetic field are measured every ten seconds, yet only a running average is recorded. The thermal stability of the magnetometer is less than 0.2 nT/°C. An Overhauser proton precession magnetometer (Geomag SM90R) located on a nearby pole yields the absolute magnetic field value. Analog signals from both magnetometers are directed to a second dome hosting the electronic equipment (Fig. 2). An 80-metre long cable conveys the information in digital form to a PC located in a nearby house. The data are downloaded twice weekly through a telephone line.

  < Figure 1 - Figure 2 >

Data from 1999 to date are publicly available. File format is text, one day per file, with following content, from minute 00:00 to minute 23:59:

UT: Universal time

Q: Quality of F measurement

F: Amplitude of magnetic field

dX, dY, dZ: variations of North, East and vertical components

Tf: Temperature of fluxgate magnetometer

Te: Temperature of electronic equipment

The true magnitude of each field component is obtained by adding the variations to the baseline.

The Swiss AMOS is operated by the Group of Geomagnetism, University of Neuchâtel and receives financial support of the Swiss Geophysical Commission.

To obtain data files from the Swiss AMOS, please contact pierre.schnegg@unine.ch

The value of the magnetic field anywhere in Switzerland is available by clicking here.