Earth Planets Space, Vol. 58 (No. 4), pp. 359-370, 2006
Nils Olsen1, Roger Haagmans2, Terence J. Sabaka3, Alexei Kuvshinov1, Stefan Maus4, Michael E. Purucker3, Martin Rother5, Vincent Lesur6, and Mioara Mandea5,7
1Danish National Space Center, Juliane Maries Vej 30, DK-2100 Copenhagen, Denmark
2Directorate of Earth Observation Programmes, ESTEC/ESA, Postbus 299, NL-2200 AG Noordwijk ZH, The Netherlands
3Geodynamics Branch, GSFC/NASA, Greenbelt, MD 20771, U.S.A.
4National Geophysical Data Center, NOAA, Boulder, CO 80305-3328, U.S.A.
5GFZ Potsdam, Telegrafenberg, D-14473 Potsdam, Germany
6British Geological Survey, Murchison House, West Mains Road, Edinburgh EH9 3LA, Scotland
7Institut de Physique du Globe de Paris, 4, Place Jussieu, B89, Tour 24, F-75252 Paris cedex 054, France
(Received November 19, 2004; Revised June 20, 2005; Accepted June 22, 2005; Online published April 14, 2006)
Swarm, a satellite constellation to measure Earth's magnetic field with unpreceded accuracy, has been selected by ESA for launch in 2009. The mission will provide the best ever survey of the geomagnetic field and its temporal evolution, in order to gain new insights into the Earth system by improving our understanding of the Earth's interior and climate. An End-to-End mission performance simulation was carried out during Phase A of the mission, with the aim of analyzing the key system requirements, particularly with respect to the number of Swarm satellites and their orbits related to the science objectives of Swarm. In order to be able to use realistic parameters of the Earth's environment, the mission simulation starts at January 1, 1997 and lasts until re-entry of the lower satellites five years later. Synthetic magnetic field values were generated for all relevant contributions to Earth's magnetic field: core and lithospheric fields, fields due to currents in the ionosphere and magnetosphere, due to their secondary, induced, currents in the oceans, lithosphere and mantle, and fields due to currents coupling the ionosphere and magnetosphere. Several independent methods were applied to the synthetic data to analyze various aspects of field recovery in relation to different number of satellites, different constellations and realistic noise sources. This paper gives an overview of the study activities, describes the generation of the synthetic data, and assesses the obtained results.
Key words: Earth's magnetic field, comprehensive inversion, electromagnetic induction, ionosphere, lithosphere, magnetosphere.