Solar, geomagnetic and local ionospheric activity (Dourbes) measurements during the period 15–21 March 2015: Solar sunspot index, S _N (A), local magnetic index K at Dourbes (B), Dst index (C), GPS TEC (D), f _o F₂ (E), h′F₂ (F) and ionospheric slab thickness (G). Instantaneous measurements denoted with dots and the 27-day medians (based on data from 4 to 30 March) plotted with solid (grey) curves. The standard deviation (2σ), centred on the median, is given by vertical (grey) bars.