Two Branch members have contributed to recent uses of Oersted magnetic field data in two very different ways.
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Terry Sabaka was part of the team that produced the 2000 International Geomagnetic Reference Field (IGRF) derived from Oersted data [Olsen, Sabaka and Toffner- Clausen, Earth Planets Space 52, 1175-1182, 2000]. A short article by Charles Barton of Australia in the July 2, 2002 issue of EOS reports that the high quality of the new IGRF allowed him to pinpoint the location of the magnetic dip pole (where the Earth's field is vertical at the surface), to an unprecedented accuracy of 1.6 km. |
| The location of this point moves at 4-8 km/yr, so models that can show the change in the magnetic field over time (e.g., figure to the right) are important. |
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Contact: Terry Sabaka, GSFC, Code 921 (sabaka@geomag.gsfc.nasa.gov)
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In a recent example of the comparison of Oersted data with that from Magsat, Pat Taylor was a co-author on a paper by H. R. Kim and others which shows that "Oersted verifies regional magnetic anomalies of the Antarctic lithosphere" [in Geophysical Research Letters, 29, #15, 10.1029/2001GL013662, 2002]. |
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The anomalies seen in Oersted data (left, bottom) are similar in size and in location to those seen by Magsat in 1980 (left, top), despite the higher orbit of Oersted (650-865 km) compared to Magsat (350-550 km). That both satellites see the same features at very different epochs and at different seasons (which affects the external currents which must be removed to isolate the crustal sources is also confirmation of a crustal nature. Oersted will provide important new information on the crust as well on the main field. |
Contact: Pat Taylor, GSFC, Code 921 (ptaylor@ltpmail.gsfc.nasa.gov)
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Responsible NASA official: Dr. Herbert Frey