Figure 10
Projection of the coefficients z( t ) on the first eigen modes, and comparison with the K p index. Top: monthly averages of the K p index (see e.g., Menvielle and Berthelier 1991). Bottom: normalized projection of the coefficient vectors \(\tilde {z}_{n}^{m}\) on the first four eigen modes \({\mathcal {Z}}_{1}\) to \({\mathcal {Z}}_{4}\), which represent 70.6% (top left), 9.4% (top right), 5.2% (bottom left), and 4.5% (bottom right) of the \(\tilde {z}_{n}^{m}\) variances.