• WG6. Magnetic Data and Observations

Coordination: Paulo Ribeiro, UC
Co-coordination: Jorge Cruz, IPMA
Institutions: FCUL, IPMA, UC

Working group focused at coordinating and modernizing the infrastructure for the acquisition and distribution of magnetic data, and for associated products and services.

Aims to transfer the Coimbra magnetic observatory (COI), to create the Ilha das Flores magnetic observatory, to install the São Teotónio magnetic station (STT), to reoccupy the network of secular variation stations and to operationalize data sharing.

More on WG6 here.


  • Provisional time series (1-min) of geomagnetic variations from the Coimbra Observatory (.txt)

Unprocessed series of the relative values ​​of the components H, D and Z and absolute values ​​of F (total field), acquired respectively by the variometer FGE and magnetometer GSM-90F1 from the Coimbra Observatory; series available since 2007.


  • Definitive time series (1-min, hourly, annual) of geomagnetic variations from the Coimbra Observatory (.txt)

Processed series of the values ​​of the geomagnetic field of the Coimbra Observatory: minute (since 2007), hourly (since 1964) and annual (since 1866) averages.


  • Monthly geomagnetic bulletins of the Coimbra Observatory (.pdf)

Monthly bulletins containing preliminary data on the geomagnetic field (mean values ​​and amplitudes), K indices (three-hourly) of geomagnetic activity, indication of the 5 most calm and disturbed days, and identification and characterization of the main geomagnetic disturbances.


  • Series of monthly mean values of diurnal geomagnetic variation from the Coimbra Observatory (.txt)

Series of monthly values ​​(1-min, hourly) of the average daytime variation (using every day) and the daytime solar variation of calm days (Sq, using the 5 geomagnetically calmest days).


  • Series of K indices of geomagnetic activity from the Coimbra Observatory (.txt)

The tri-hourly index K, used to characterize the local geomagnetic activity, is determined based on a semi-logarithmic scale (0-9) in which each integer measures the maximum amplitude (in relation to the daytime variation curve Sq) of the variation the horizontal components of the geomagnetic field; series available since 2007.


  • (available soon)
    • Total field time series (1-min) (F) of the São Teotónio magnetic station
    • Electric field maps induced by geomagnetic storms
    • Magnetic maps from mainland Portugal
    • Magnetic charts from the Portuguese continental shelf
More sources of magnetic data: SuperMAG, INTERMAGNET, WDC, IMAGE, ISGI.



  • Absolute determination of magnetic declination in airports and aerodromes

Survey of magnetic declination (angular difference between Geographic North and Magnetic North) required for air navigation according to the rules of visual flight. Magnetic declination is an aeronautical data made available in Aeronautical Information Publications (VFR Manual and aeronautical charts).

  • (available soon)
    • Monitoring of geomagnetic activity in Continental Portugal and in the Azores
    • Comparison of instruments with the standard of magnetic observatories
    • Learning and training for users of geomagnetic observation instruments



  • (available soon)
    • Learning and training for users of geomagnetic observation instruments

Check more TRAINING available via C4G.



  • DI-flux magnetometer of absolute observations
  • Scalar Overhauser magnetometers
  • Scalar proton magnetometers
  • Scalar cesium vapour magnetometer
  • Triaxial fluxgate magnetometer

Check more EQUIPMENT available via C4G.

More on the Geophysical and Astronomical Observatory of the University of Coimbra GAOUC and on
worldwide geomagnetic observatories IAGA.