Fourteen years of geomagnetic daily variation at Mario Zucchelli Station (Antarctica)

Abstract

During the 1986-87 austral summer a geomagnetic observatory was installed
at the Italian Antarctic Base Mario Zucchelli Station. In the first three years
continuous time variation monitoring and absolute measurements of the
geomagnetic field were carried out only during summer expeditions. Starting
1991 an automatic acquisition system, operating through all the year, was put
in operation. We present here some peculiarities of the daily variation as
observed for fourteen years (1987-2000). The availability of a long series of
data has allowed the definition of seasonal, as well as solar cycle effects, on
short time variations as observed at a cusp-cap observatory. In particular,
contrary to mid latitude behaviour, a clear dependence of the daily variation
amplitude on the global geomagnetic K index was well defined.