Daily variation at three Antarctic geomagnetic observatories within the polar cap

• Published in: Annales geophysicae (1988) Vol. 26; no. 8; pp. 2179 - 2190
• Main Authors: PIETROLUNGO, M, LEPIDI, S, CAFARELLA, L, SANTARELLI, L, DI MAURO, D
• Format: Journal Article
• Language: English
• Published: Katlenburg-Lindau European Geophysical Society 01-01-2008; Copernicus GmbH; Copernicus Publications
• Subjects: Analysis; Earth, ocean, space; Exact sciences and technology; External geophysics; Ice caps; Magnetic fields; Magnetosphere; Physics of the ionosphere; Physics of the magnetosphere; polar regions; Antarctica; PS, Antarctica, Ross Dependency, Terra Nova Bay; Interplanetary magnetic field; High latitude; time variations; Position; daily variations; Nova; solar radiation; solar wind; diurnal variations; Polar Cap; magnetosphere; Winter; Reference system; Magnetospheric physics (Polar cap phenomena; Solar wind-magnetosphere interactions); statistical analysis; Geomagnetic activity; Geomagnetism and paleomagnetism (Time variations, diurnal to secular)
• ISSN: 0992-7689; 1432-0576; 1432-0576
• DOI: 10.5194/angeo-26-2179-2008

In this work we present a statistical analysis of the diurnal variation as observed at three Antarctic observatories located at different positions within the polar cap during the year 2006. Data used for the analysis are from the Italian geomagnetic observatory at Mario Zucchelli Station (formerly Terra Nova Bay, geographic latitude 74.7° S, corrected geomagnetic latitude 80.0° S), from the French-Italian observatory at Concordia Station (75.1° S, 88.9° S) and from the French observatory at Dumont D'Urville (66.7° S, 80.4° S), which are located in pairs at the same geographic and corrected geomagnetic latitude; such a position allows to distinguish whether the geographic or the geomagnetic reference system is better suitable to describe the observed phenomena at so high latitudes. The peculiarities of the daily variation as observed during this year and its relation with the observatory location and magnetospheric and interplanetary conditions were analysed. Data were also studied taking into account different Lloyd seasons. The results indicate that the 24-h variation is quite persistent, but its amplitude strongly depends on season and global geomagnetic activity: indeed, it almost vanishes during local winter for quiet geomagnetic conditions; this reduction is more evident at the stations closer to the geographic pole, where the solar radiation reduction during winter is more dramatic. The Interplanetary Magnetic Field orientation has been found to be important in that the north-south and the east-west components control the amplitude and the diurnal pattern of the variation, respectively.