Daily variation at Concordia station (Antarctica) and its dependence on IMF conditions

• Main Authors: Cafarella, L., Di Mauro, D., Lepidi, S., Meloni, A., Pietrolungo, M., Santarelli, L., Schott, J. J.
• Other Authors: Istituto Nazionale di Geofisica e Vulcanologia, Institut de physique du globe de Strasbourg (IPGS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2007
• Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; [SDU.STU]Sciences of the Universe [physics]/Earth Sciences; Concordia Station; Antarc*; Antarctica; Geomagnetic Pole
• Online Access: https://hal.archives-ouvertes.fr/hal-00330146; https://hal.archives-ouvertes.fr/hal-00330146/document; https://hal.archives-ouvertes.fr/hal-00330146/file/angeo-25-2045-2007.pdf

International audience After some short test surveys, during the 2004–2005 summer expedition in Antarctica, a geomagnetic French-Italian observatory was installed on the plateau (geographic coordinates: 75.1° S, 123.4° E; corrected geomagnetic coordinates: 88.9° S, 54.3° E; UT=LT-8) very close to the geomagnetic pole. In this paper we present some peculiarities of the daily variation as observed at this polar cap observatory during the years 2005 and 2006, taking into account the different Loyd seasons and different interplanetary magnetic field conditions. Some interesting results emerge from the analysis, confirming the dependence of the daily variation (and of the associated polar current systems) on the IMF B z and B y components. In particular the analysis showed that different B z conditions correspond to different contribution to daily variation of ionospheric and field aligned currents, while particular B y conditions lead to a time shift of the diurnal variation, indicating an asymmetry with respect to the noon meridian.