Four decades of geomagnetic and solar activity: 1960–2001

We analyze the relationship between some space weather indices (Dst, Ap, F10.7) and geomagnetic effects on the regional (European) scale, over the period 1960–2001. The remaining external field signal (RES) detected in the Northward magnetic component of the European observatory annual means are used as an indicator of the regional geomagnetic activity. Relationship RES-F10.7 suggests correction factors for getting the geomagnetic annual means of the Northern component less affected by the external sources. We have found some time lags among investigated parameters. These delays may suggest that the Ap responds to the solar activity in a differently than Dst and RES, Ap being more sensitive to the high-speed streams (HSS) and the Alfvenic waves present in HSS, while Dst and RES being more influenced by the coronal mass ejections activity (CME).