Fig. 8From: Geomagnetic core field models and secular variation forecasts for the 13th International Geomagnetic Reference Field (IGRF-13)Comparison of six observed and predicted secular variation coefficients with the largest amplitude at Earth’s surface. Model 1 (dashed black line), Model 2 (dashed red line) and their forecasts (solid lines). Vertical lines labeled with a and b mark two possible geomagnetic jerks. The other labels mark occurrences of known jerksBack to article page