DTU Space is monitoring the Earths magnetic field with a network of ground stations in Greenland, Denmark, and the South Atlantic. An array with 18 stations at coastal locations 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, BFE and TDC are geomagnetic observatories and calibrated to INTERMAGNET standards.
List of magnetic ground stations
Maps of magnetic ground stations
Instrumentation and data
Magnetogram stack plots
Cooperations and links
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 84.46 28.35 online 01/82(1956)
Thule Air Base TAB 76.54 291.18 83.61 26.44 online 07/13
Savissivik SVS 76.02 294.90 82.71 32.05 online 08/83
Kullorsuaq KUV 74.57 302.82 80.35 41.11 online 07/82
Upernavik UPN 72.78 303.85 78.57 39.46 online 04/82
Uummannaq Umanaq UMQ 70.68 307.87 75.97 41.87 online 09/82
Qeqertarsuaq + Godhavn GDH 69.25 306.47 74.83 38.72 online 01/82(1926)
Attu ATU 67.93 306.43 73.56 37.56 online 06/85
Kangerlussuaq Sondre Stromfjord STF 67.02 309.28 72.18 40.25 online 08/82
Maniitsoq Sukkertoppen SKT 65.42 307.10 70.98 36.66 online 06/86
Nuuk Godthaab GHB 64.17 308.27 69.52 37.32 online 11/81
Paamiut Frederikshaab FHB 62.00 310.32 66.92 38.56 online 11/81
Narsarsuaq + NAQ 61.16 314.56 65.22 42.68 online 01/82(1983)
Greenland East Coast (DTU)
Nord Nord NRD 81.60 343.33 81.02 100.27 1-5 months 09/81
Danmarkshavn DMH 76.77 341.37 76.98 83.34 online 02/82
Daneborg DNB 74.30 339.78 74.78 77.41 ------ 09/82 12/06
Ittoqqortoormiit Scoresbysund SCO 70.48 338.03 71.15 70.90 online 01/81
Tasiilaq Ammassalik AMK 65.60 322.37 68.46 52.85 online 09/91
Greenland Ice Cap (VT)
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
Brorfelde + BFE 55.63 11.67 51.86 89.13 online 1980
Rømø ROE 55.17 8.55 51.45 86.37 online 09/05
South Atlantic (DTU)
Tristan de Cunha + TDC -37.10 347.69 -40.57 49.11 online 10/09
The Quasi-Dipole (QD) geomagnetic coordinates are calculated after Emmert et al., , with IGRF11 coefficients, for a geodetic height of 0 km, and for epoch 2010.0 (*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.
Maps of ground magnetic stations
DTU Space operates the Greenland magnetometer array, including 18 variometer stations and 3 geomagnetic observatories. This array constists of a West Coast Chain with 13 stations including three observatories between 77.47 and 61.16 geographic North. 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 runs a geomagnetic observatory on the island Tristan de Cunha since 2009 (Total field recordings were commenced in 2008.). This region 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 and more information about the technical specifications can be found here.
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.
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 Jürgen Matzka and Anna Willer for more information on data requests.
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 Jürgen Matzka for detailed information on commercial data use.
Near real time magnetogram stack plots are provided in cooperation with Tromsø Geophysical Observatory.
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.