Resolution of direction of oceanic magnetic lineations by the sixth‐generation lithospheric magnetic field model from CHAMP satellite magnetic measurements

The CHAMP satellite continues to provide highly accurate magnetic field measurements from decreasing orbital altitudes (<350 km) at solar minimum conditions. Using the latest 4 years (2004–2007) of readings from the CHAMP fluxgate magnetometer, including an improved scalar data product, we have estimated the lithospheric magnetic field to spherical harmonic degree 120, corresponding to 333 km wavelength resolution. The data were found to be sensitive to crustal field variations up to degree 150 (down to 266 km wavelength), but a clean separation of the lithospheric signal from ionospheric and magnetospheric noise sources was achieved only to degree 120. This new MF6 model is the first satellite-based magnetic model to resolve the direction of oceanic magnetic lineations, revealing the age structure of oceanic crust.

[1]  Nils Olsen,et al.  Extending comprehensive models of the Earth's magnetic field with Ørsted and CHAMP data , 2004 .

[2]  Hermann Lühr,et al.  Fifth‐generation lithospheric magnetic field model from CHAMP satellite measurements , 2007 .

[3]  J. Cain,et al.  Derivation of a geomagnetic model to n=63 , 1989 .

[4]  Richard J. Blakely,et al.  The Magnetic Field of the Earth's Lithosphere: The Satellite Perspective , 1999 .

[5]  Douglas Alsdorf,et al.  Global vector and scalar Magsat magnetic anomaly maps , 1995 .

[6]  George E. Backus,et al.  Non‐uniqueness of the external geomagnetic field determined by surface intensity measurements , 1970 .

[7]  H. Lühr,et al.  Search for magnetically quiet CHAMP polar passes and the characteristics of ionospheric currents during the dark season , 2006 .

[8]  R. Merrill.  The magnetic field of the earth , 1996 .

[9]  Jafar Arkani-Hamed,et al.  Scalar magnetic anomaly maps of Earth derived from POGO and Magsat data , 1994 .

[10]  Mioara Mandea,et al.  GRIMM: the GFZ Reference Internal Magnetic Model based on vector satellite and observatory data , 2008 .

[11]  Nils Olsen,et al.  Earth's lithospheric magnetic field determined to spherical harmonic degree 90 from CHAMP satellite measurements , 2006 .

[12]  Dhananjay Ravat,et al.  National Geophysical Data Center candidate for the World Digital Magnetic Anomaly Map , 2007 .

[13]  Walter R. Roest,et al.  Age, spreading rates, and spreading asymmetry of the world's ocean crust , 2008 .

[14]  Mioara Mandea,et al.  CHAOS—a model of the Earth's magnetic field derived from CHAMP, Ørsted, and SAC‐C magnetic satellite data , 2006 .

[15]  Robert D. Regan,et al.  A global magnetic anomaly map , 1975 .

[16]  Nils Olsen,et al.  First scalar magnetic anomaly map from CHAMP satellite data indicates weak lithospheric field , 2002 .

[17]  Georgios Balasis,et al.  Magnetic signatures of equatorial spread F as observed by the CHAMP satellite , 2006 .

[18]  N. Olsen,et al.  3-D Modelling of the Magnetic Fields Due to Ocean Tidal Flow , 2005 .