Time structure of the 1991 magnetic jerk in the core-mantle boundary zone by inverting global magnetic data supported by satellite measurements

New global magnetic data - Gauss coefficients tip to degree and order 5, monthly values from 1980 to 2000, fitted to global data and partly based on high-quality satellite vector data of Magsat and CHAMP/ORSTED - are processed with a recent non-harmonic downward continuation method (Ballani et. al. 2002). Using a weakly conducting mantle and the highly conducting fluid in the outer core we investigate the temporal structure of the 1991 jerk below some geomagnetic stations calculating the component dY/dt at the core-mantle boundary and underneath in different depths of the fluid outer core assuming fluid velocity. 7 there. The jerk structure dissolves and differs considerably in magnitude and in phase front the harmonically downward continued component.