Figure 7
SV (bottom, units: \(\log _{10}\), in nT/year) and MF (top, unit: \(\log _{10}\), in nT) spectra at Earth surface (2014.5). For the COV-OBS.x1 observations (green circled line) and observation errors (green line), the ensemble average forecast (red stars dotted line, superimposed to the spectrum of the observations), the ensemble average forecast errors (dark red), the ensemble average analysis errors (cyan). Superimposed (in dotted orange) to the SV spectra is that for the SV model error 
.