Eso no es riguroso, es un ajuste adhoc sin comprobación. Me explico.
Eso es absurdo.
No se trata de un modelo predictivo sino de medidas independientes.
No hay ajustes. El geomagnetic index es una medida mas extensa de la actividad solar, ya que incluye actividad magnetica no asociada a manchas solares: "The study examined the geoeffectiveness of coronal mass ejections (CME) separated into two types – magnetic cloud (MC) and non-MC CMEs (CME), and coronal holes (CH)"
http://sait.oat.ts.astro.it/MSAIt760405/PDF/2005MmSAI..76..969G.pdf"In Figure 6 the
long-term variations in global temperature are
compared to the long-term variations in geo-
magnetic activity as expressed by the ak-index
(Nevanlinna and Kataja 2003). The correlation
between the two quantities is 0.85 with p<0.01
for the whole period studied"
figure 6 es la publicada en el post anterior.
El indice se explica aqui.
Nevanlinna, H., and E. Kataja (1993), An extension of the geomagnetic activity index series aa for two solar cycles (1844–1868), Geophys. Res. Lett., 20(23), 2703–2706.
Edito para añadir la figura 6: