Fig. 9From: Geomagnetic core field models and secular variation forecasts for the 13th International Geomagnetic Reference Field (IGRF-13)Evolution of the toroidal flow coefficients \(t_1^0\) (left) and \(t_3^0\) (right); their past variations (black) and their forecasts (red) based on the MSSA. The vertical line labeled with FC marks the start of the forecastBack to article page