Fig. 5
From: The CHAOS-7 geomagnetic field model and observed changes in the South Atlantic Anomaly
Top row: 1-D best fit conductivity profile (left) from Grayver et al. (2017) used in this study [red dashes, labelled “Grayver et al. (2017)”] and a hypothetical case with increased conductivity in the lower mantle (blue line, labelled “anomalous”). The Earth’s core, at depths below 2850 km, is assumed to have a finite conductivity of \(10^6\) S/m, which is off the edge of the plot. The magnitude of the corresponding discrete impulse response (right) for the \({\tilde{Q}}_{11}^{00}\) transfer function. Bottom row: \({\tilde{Q}}_{11}^{00}\) transfer function in frequency domain, real part (left) and imaginary part (right)