Journal cover Journal topic
Annales Geophysicae An interactive open-access journal of the European Geosciences Union
Journal topic

Journal metrics

Journal metrics

  • IF value: 1.621 IF 1.621
  • IF 5-year value: 1.614 IF 5-year 1.614
  • CiteScore value: 1.61 CiteScore 1.61
  • SNIP value: 0.900 SNIP 0.900
  • SJR value: 0.910 SJR 0.910
  • IPP value: 1.58 IPP 1.58
  • h5-index value: 24 h5-index 24
  • Scimago H index value: 80 Scimago H index 80
Volume 36, issue 1 | Copyright
Ann. Geophys., 36, 193-203, 2018
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.

Regular paper 08 Feb 2018

Regular paper | 08 Feb 2018

The geomagnetic coast effect at two 80° S stations in Antarctica, observed in the ULF range

Mauro Regi1, Marcello De Lauretis1, Patrizia Francia1, Stefania Lepidi2, Andrea Piancatelli1, and Stefano Urbini2 Mauro Regi et al.
  • 1Dipartimento di Scienze Fisiche e Chimiche, Università degli Studi dell'Aquila, L'Aquila, 67100, Italy
  • 2Istituto Nazionale di Geofisica e Vulcanologia, Rome, 00143, Italy

Abstract. We examined the coast effect in Antarctica along the 80°S magnetic parallel. We used the geomagnetic field measurements at the two coastal stations of Mario Zucchelli Station and Scott Base, and, as a reference, at the inland temporary station Talos Dome, during 18 January–14 March 2008. Spectral analysis in the Pc5 frequency range (1–7mHz) revealed large differences between coastal and inland stations, such as higher spectral power levels in the vertical component and higher coherence between horizontal and vertical components at coastal stations. Using the interstation method on selected active time intervals, with Talos Dome as a remote reference station, we found that remote reference induction arrows are directed almost perpendicularly with respect to their respective coastlines. Moreover, the single-station analysis shows that at Talos Dome the amplitude of the induction arrows is much smaller than at coastal stations. These results clearly indicate that coast effect at a few hundred kilometers from the coastline is relatively small. The coast effect on polarization parameters was examined, for a Pc5 event that occurred on 11 March 2008. The results evidenced that the azimuthal angle of polarized signals at one of the coastal stations is largely different with respect to the inland station (by  ∼ 110°), while the polarization ratio and ellipticity attain comparable values. We proposed a correction method of the polarization parameters, which operates directly in the frequency domain, obtaining comparable azimuthal angles at coastal and inland stations.

Publications Copernicus
Short summary
Our results suggest that sea–land interface affects the polarization parameters at coastal stations. We proposed a method for directly estimating, in the frequency domain, the normal field variations at coastal stations, by inverting the linear relationship between horizontal field measurements at coastal and reference stations. Our techniques could also be used to detect possible anomalous effects due to sporadic changes in ground conductivity.
Our results suggest that sea–land interface affects the polarization parameters at coastal...