Fig. 7From: Morphology of the southern African geomagnetic field derived from observatory and repeat station survey observations: 2005–2014Secular variation of D, H, and Z components as measured between 2005 and 2014 at Hartebeesthoek observatory. The black dots show monthly mean secular variation estimates derived as running annual differences. The CHAOS-5 model (black line) and the regional SAREG model (brown dashed line) are included. Piecewise linear fits to the data provide estimates of secular acceleration as given in the legendsBack to article page