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.

Magnetogram stack plots

Maps of magnetometer ground stations

Link to magnetogram stackplots

List of magnetometer ground stations

Observatory  station name	+	Alternative or  former names	IAGA code	Geodetic (WGS84)		Quasi-Dipole geomagnetic		Data latency	Operation from to
				Lat.	Long.	Lat.	Long.		mm/yy	mm/yy
Greenland West Coast (DTU)
Qaanaaq	+	Thule	THL	77.47	290.77	84.05	26.79	online	01/82(1956)
Thule Air Base			TAB	76.54	291.18	83.19	25.25	online	07/13
Savissivik			SVS	76.02	294.90	82.31	30.73	online	08/83
Kullorsuaq			KUV	74.57	302.82	79.98	39.83	online	07/82
Upernavik			UPN	72.78	303.85	78.18	38.49	online	04/82
Uummannaq	+	Umanaq	UMQ	70.68	307.87	75.59	41.07	online	09/82
Qegertarsuaq	+	Godhavn	GDH	69.25	306.47	74.42	38.10	online	01/82(1926)
Attu			ATU	67.93	306.43	73.14	37.05	online	06/85
Kangerlussuaq	+	Sondre Stromfjord	STF	67.02	309.28	71.77	39.74	online	08/82
Maniitsoq	+	Sukkertoppen	SKT	65.42	307.10	70.54	36.29	online	06/86
Nuuk	+	Godthaab	GHB	64.17	308.27	69.07	36.99	online	11/81
Paamiut	+	Frederikshaab	FHB	62.00	310.32	66.47	38.29	online	11/81
Narsarsquaq			NAQ	61.16	314.56	64.78	42.37	online	01/82(1983)
Greenland East Coast (DTU)
Nord		Nord	NRD	81.60	343.33	81.09	97.99	1-5 months	09/81
Danmarkshavn			DMH	76.77	341.37	76.92	81.83	online	02/82
Daneborg			DNB	74.30	339.78	74.67	76.18	--------	09/82 12/06
Ittoqqortoormiit	+	Scorebysund	SCO	70.48	338.03	70.98	70.00	--------	01/81 2016
Tasiilaq	+	Ammassalik	AMK	65.60	322.37	68.11	52.26	--------	09/91 2016
Greenland Ice Cap (DTU)
Summit			SUM	72.3	312.7	75.07	57.66	online	06/14
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
Faroe Islands (DTU)
Hov			HOV	61.51	353.21	59.53	76.05	online	08/13
Denmark (DTU)
Brorfelde			BFE	55.63	11.67	51.82	88.94	online	1980
Rømø			ROE	55.17	8.55	51.39	86.18	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

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

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.

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

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 available 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 variometer sites have been extrapolated to epoch 1991. The result of these comparisons are found here.

Data request

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 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 Anna Willer for detailed information on commercial data use.

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.

ESPASis 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.

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