Mantle conductivity models derived from satellite magnetic data: results and perspective

Speaker: Alexei Kuvshinov
First I present a global 1-D conductivity model which is obtained by analysis of seven years (2001-2007) of simultaneous magnetic data from the three satellites Ørsted, CHAMP and SAC-C. Processing of the data includes removal of core and crustal fields as predicted by the xCHAOS field model. The residuals are interpreted in terms of a large-scale contribution from the magnetospheric ring current and its induced counterpart. In order to avoid ionospheric effects, only non-polar (dipole latitude below 50 deg) scalar and vector observations from the night-side sector (19 to 05 LT) are used. Transfer functions connecting internal (induced) and external (inducing) expansion coefficients of the magnetic potential are estimated in the period range from a few days to a few months. Further conductivity-depth profile of the Earth’s interior is inferred down to depths of 1500 km from the obtained transfer functions using regularized inversion techniques. New conductivity profile is compared with previous ones and the differences and similarities are discussed. Then an attempt is made to detect lateral variations of the mantle conductivity. Finally I discuss some ideas how to recover 3-D conductivity distribution in the mantle from the multi-satellite data.