Geomagnetic Variations observed at Maddalena Island, Sardinia

CONTINUOUS observations of the three components of the geomagnetic field were carried out at Maddalena Island (9° 24′ E., 41° 13′ N.), the northernmost part of Sardinia, facing the Bonifacio Straits, during the period 1958–1964 by the Hydrographic Institute of the Italian Navy (see Fig. 1). The declination at Maddalena Island was about 3.5° W. in 1959. Here we report preliminary analyses of the geomagnetic variations of short periods (a few minutes–3 h) observed at this observatory; brief summaries of the diurnal variations and the K-indices have already been published1.