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Detailed Reference Information |
Olson, P., Sumita, I. and Aurnou, J. (2002). Diffusive magnetic images of upwelling patterns in the core. Journal of Geophysical Research 107: doi: 10.1029/2001JB000384. issn: 0148-0227. |
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A new technique for imaging convection in the outer core is presented, which is based on mean field electrodynamics. The method assumes a frozen magnetic flux balance for the global-scale part of the fluid velocity in the outer core and a diffusive magnetic flux balance for smaller-scale parts of the fluid velocity. The diffusive flux balance implies that local highs and lows in the magnetic field correspond approximately to fluid downwellings and upwellings, respectively. Diffusive flux produces good images of the pattern of upwellings and downwellings near the outer boundary in numerical dynamos, except near the equator. The amplitudes of the upwellings in the diffusive magnetic images correspond to the upwelling amplitudes below the Ekman boundary layer in the numerical dynamos. We have applied this technique to the Oersted initial 2000 core field model and to time-averaged models of the historical geomagnetic field on the core-mantle boundary. It indicates that high-latitude, high magnetic flux density patches correspond to downwellings in the outer core. |
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BACKGROUND DATA FILES |
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Abstract |
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Keywords
Geomagnetism and Paleomagnetism, Core processes, Geomagnetism and Paleomagnetism, Dynamo theories, Geomagnetism and Paleomagnetism, Spatial variations (all harmonics and anomalies), Geomagnetism and Paleomagnetism, Time variations--secular and long term, Geomagnetism and Paleomagnetism, Geomagnetic induction |
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Publisher
American Geophysical Union 2000 Florida Avenue N.W. Washington, D.C. 20009-1277 USA 1-202-462-6900 1-202-328-0566 service@agu.org |
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