Magnetic Ground Stations

DTU Space is monitoring the Earths magnetic field with a network of ground stations in Greenland, Faroe Islands and Denmark. An array with 18 stations at coastal locations and one on the Ice Cap is operated in Greenland. Previously 5 stations were maintained on the Greenland Ice Cap in cooperation with Virginia Tech, USA. All stations provide full vector geomagnetic field information with 1 Hz resolution. THL, GDH, NAQ and BFE are geomagnetic observatories and calibrated to INTERMAGNET standards.

Maps of magnetic ground stations
Magnetogram stack plots
List of magnetic ground stations
Instrumentation and data
Data request
Cooperations and links

Maps of ground magnetic stations


Link to magnetogram stackplots


Geomagnetic ground stations, DTU Space 




List of magnetic ground stations

                                               geodetic      Quasi-Dipole      Data      Operation 
observatory (+)    alternative or    IAGA      (WGS84)       geomagnetic      latency    from   to  
station name       former names      code    Lat.   Long.    Lat.  Long.                 mm/yy mm/yy
Greenland West Coast (DTU)
Qaanaaq      +     Thule              THL   77.47  290.77    83.97  26.61     online     01/82(1956) 
Thule Air Base                        TAB   76.54  291.18    83.12  25.12     online     07/13
Savissivik                            SVS   76.02  294.90    82.24  30.58     online     08/83 
Kullorsuaq                            KUV   74.57  302.82    79.91  39.67     online     07/82
Upernavik                             UPN   72.78  303.85    78.11  38.37     online     04/82
Uummannaq          Umanaq             UMQ   70.68  307.87    75.52  40.99     online     09/82
Qeqertarsuaq +     Godhavn            GDH   69.25  306.47    74.35  38.04     online     01/82(1926)
Attu                                  ATU   67.93  306.43    73.07  37.01     online     06/85 
Kangerlussuaq      Sondre Stromfjord  STF   67.02  309.28    71.70  39.70     online     08/82
Maniitsoq          Sukkertoppen       SKT   65.42  307.10    70.46  36.27     online     06/86 
Nuuk               Godthaab           GHB   64.17  308.27    68.99  36.98     online     11/81
Paamiut            Frederikshaab      FHB   62.00  310.32    66.38  38.28     online     11/81
Narsarsuaq   +                        NAQ   61.16  314.56    64.70  42.36     online     01/82(1983)
Greenland East Coast (DTU)
Nord               Nord               NRD   81.60  343.33    81.10  97.62   1-5 months   09/81
Danmarkshavn                          DMH   76.77  341.37    76.90  81.60     online     02/82
Daneborg                              DNB   74.30  339.78    74.65  76.00     ------     09/82 12/06
Ittoqqortoormiit   Scoresbysund       SCO   70.48  338.03    70.94  69.88     online     01/81
Tasiilaq           Ammassalik         AMK   65.60  322.37    68.05  52.20     online     09/91
Greenland Ice Cap (VT)
Summit                                SUM   72.3   321.7     75.02  57.52      online    06/14
MAGIC-1 North *                       MCN   73.93  322.38    77.26  65.04      ------    07/92 06/97
MAGIC-1 East  *                       MCE   72.40  326.10    75.22  65.65      ------    07/92 06/96
MAGIC-1 West  *                       MCW   72.00  317.41    76.31  56.67      ------    07/92 06/97
MAGIC-1 GISP  *    Summit             MCG   72.57  321.55    76.14  61.72      ------    07/91 05/97
MAGIC-2 GISP  **   Summit             MCG   72.60  321.65    75.82  59.90      ------    08/97 06/06
MAGIC-2 Raven **   DYB,DYE2,PITTS     MCR   66.48  313.71    71.15  45.11      ------    08/97 06/06
Denmark (DTU)
Brorfelde    +                        BFE   55.63   11.67    51.82  88.94     online     1980
Rømø                                  ROE   55.17    8.55    51.37  86.17     online     09/05
South Atlantic (DTU & GFZ)
Tristan de Cunha +                    TDC  -37.10  347.69   -41.19  49.98     online     10/09 12/16


 The Quasi-Dipole (QD) geomagnetic coordinates are calculated after Emmert et al., [2010], with IGRF12 coefficients, for a geodetic height of 0 km, and for epoch 2015.0 (*epoch 1997.0, **epoch 2006.0).
The data transfer delay denotes the time elapsed between observation and arrival of the data at DTU Space. When the station is "online", observations can be accessed in only few minutes.

The operation time indicates the time since when the data is available in digital form. The additional year information for observatories tells the time from when the observatory was in operation. For observatories data is available from their operation start onwards. Please note, that continuous observations cannot be guaranteed throughout the entire period.

Emmert, J.T., A.D. Richmond, and D.P. Drob, A computationally compact representation of magnetic Apex and Quasi-Dipole coordinates with smooth base vectors, J. Geophys. Res., 115, A08322, doi:10.1029/2010JA015326, 2010.



Instrumentation and data

Greenland Array

DTU Space operates the Greenland magnetometer array, including 19 variometer stations whereof 3 are geomagnetic observatories. This array consists of a West Coast Chain with 13 stations including three observatories between 77.47 and 61.16 geographic North. One station are located on the Ice Cap at 72.3 degrees Geographic North and on the East Coast 5 variometer stations are located between 81.6 and 65.6 geographic North.

The data base of 5 Greenland Ice Cap variometer stations in cooperation with Virginia Tech, USA, operated between 1991 and 2006. A more detailed description of the Magnetometer Array on the Greenland Ice Cap (MAGIC sites) is available from the website of the Magnetosphere-Ionosphere Science Team (MIST).

The Greenland Array covers polar cap, cusp and auroral regions. These data allow the monitoring of electromagnetic processes in the polar ionosphere and magnetosphere, and are a significant contribution to global data sets.


Our global magnetometer operations include one observatory (Brorfelde) and one variometer station (Rømø) in Denmark.

Tristan de Cunha 

In the South Atlantic Magnetic Field Anomaly (SAA) DTU Space monitored a geomagnetic observatory on the island Tristan de Cunha from 2009 - 2016 (Total field recordings were commenced in 2008). The station is now monitored by the German Research Centre for Geosciences (GFZ). The region around Tristan de Cunha is characterised by the lowest values of the Earth magnetic field globally which makes it penetrable for energetic partical radiation from space. During the last 20 years, the magnetic field strength in the SAA has weakened by almost 8%.



The vast majority of the sensors now employed are the Danish FGE 3-axis linear-core fluxgate magnetometers designed and built under the supervision of Ole Rasmussen and later Lars William Pedersen. They are optimized for long-term stability (observatory-quality instruments) rather than high sensitivity. The stations use 16 bit A/D converters with 20s or 1s sampling rate, optimized for 1 minute mean data. Hence, the rms-noise is approximately 0.1 nT in the 1 mHz - 1 Hz band, the time accuracy is 1s and the final resolution is 0.25 nT for most data at 20s sampling rate and 0.125 nT for most data at 1s sampling rate. During setup, the sensor axes are oriented along local magnetic north (H), local magnetic east (E) and vertical down (Z). Sensors at some stations are equipped with a suspension which guarantees vertical alignment. The instruments run fully automatically and require (normally) no manual intervention. All stations use the FGE vector magnetometer. More information about the technical specifications can be found here.


Data pre-processing

A few months after the end of the calendar year (typically in the spring of the following year) quiet levels (also termed reference levels) are determined for all three magnetic field components at each stations. Each daily data record is then tagged with a set of numbers representing the set of quiet levels. If no quiet level could be determined (e.g., because of jumps, significant drifts etc.), the data are flagged accordingly.

Time resolution and formats available

Greenland magnetometer data has been aquired in digital form since 1981. From 1981 through 1990 all stations recorded with 1-min sampling rate. In 1986 the acquisition systems was gradually modified in order to record with 20-s sampling rate. Modification was completed by 1991, and since then all stations run at 20-s sampling rate. In 1999 acquisition system was made capable to record at 1-s sampling in addition to the continued 20-s sampoling rate. In 2001 most stations were upgraded, and in the summer of 2002 the upgrade was completed. Now all stations have laptops as dataloggers recording at 1Hz.

The data files can be provided according to IAGA2000 and IAGA2002 formats. The magnetic observations are available in the local magnetic coordinate system of the setup or re-adjustment time of the instrument to the local geomagnetic coordinate system. The data are also availble in the geographic coordinate system. This is realised by a rotation of the horizontal magnetic field around the vertical axis by IGRF-11 declinations for each site.

Comparison between declination measurements from the three Greenland observatories, NAQ, GDH and THL (see map above) and IGRF-11 model results, made over the 1981-2001 time span, revealed very good agreement between IGRF-11 model declination and observed local declination at the observatory sites. During a survey carried out in the summer of 1990 the magnetic declination was actually measured at a number of Greenland west coast magnetometer sites as well. Also these data revealed satisfactory agreement with the local declination obtained from the IGRF-11 model. For comparison the observations at the variomter sites have been extrapolated to epoch 1991. The result of these comparisons are found here.


Data request

Scientific use:

Magnetic observations in pre-processed or unprocessed form are freely available for scientific users, see DTU Space data policy. A data download website at DTU Space is currently under construction. Users should contact acting principal investigator Anna Willer for more information on data requests.

Commercial use:

Ground based magnetic observations are used for directional drilling, exploration by geophysical surveys, and other industry applications. DTU Space is cooperating with several commercial partners and customers. Please contact Anna Willer for detailed information on commercial data use.




40th Anniversary of the Greenland Magnetometer Array and IMAGE 2013 Meeting



Cooperations and links


The World Data Center Copenhagen (WDC Copenhagen) is member of the ICSU World Data System and is holding extensive archives of magnetograms and other geomagnetic observatory data products that predate the introduction of digital data recording. Additionally, the WDC has an ftp-server to distributes the Northern PC index derived from the geomagnetic observatory Qaanaaq (THL) and the Kp-index data products derived at the geomagnetic observatory Niemegk (NGK).


Tromsø Geophysical Observatory pre-processes and provides magnetic observations from DTU Space sites. Online data are available for scientific and commercial interests.


The Magnetosphere - Ionosphere Science Team (MIST) now led by the Space Physics Research Group at Virginia Tech, USA has run and maintained the MAGIC variometer stations. Ongoing collaboration exists in terms of data request and interpretation. The MIST team is involved in building an Antarctic magnetometer array at near conjucate sites to the Greenland magnetometer array.


ESPAS is co-funded by the European Commission under the 7th Framework Programme (EU website). ESPAS will provide the e-Infrastructure necessary to support the access to observations and prediction of the Near-Earth Space environment. A primary goal is to facilitate user access to heterogeneous data from multiple providers.


SuperMAG is a worldwide collaboration of ground based magnetometers generously supported by the National Science Foundation and NASA. It currently includes data from more than 200 stations generously provided by a long list of organizations and national agencies.



The INTERMAGNET programme establishes a global network of cooperating digital magnetic observatories, adopting modern standard specifications for measuring and recording equipment, in order to facilitate data exchanges and the production of geomagnetic products in close to real time.


ULTIMA is an international consortium that aims at promoting collaborative research on the magnetosphere, ionosphere, and upper atmosphere through the use of groundbased magnetic field observatories. ULTIMA is composed of individual magnetometer arrays in different countries/regions.




Anna Naemi Willer
Academic staff
DTU Space
+45 45 25 97 40