Friday, 31 August 2007 - 12:00 PM
5.A.A-5
The Contribution of Geomagnetic Observatories and Magnetic Models to the Study of Secular Variation and Jerks in Antarctica
Antonio Meloni, Paola De Michelis, Lili Cafarella, and Roberta Tozzi. INGV, Via di Vigna Murata 605, 00143 Rome, Italy
Some of the most interesting features of the geomagnetic field and of its time variations are displayed in polar areas. Observatory monthly means usually provide an excellent opportunity to study the temporal changes of the magnetic field at a given location. Unfortunately, on the Antarctic continent the distribution of the permanent ground-based observatories does not permit a uniform coverage of the examined area. Furthermore, the magnetic records are characterized by intensive external disturbances and noise that make the analysis of the magnetic field difficult. To improve our knowledge on secular variation and detect the presence of secular variation impulses (geomagnetic jerks) in Antarctica, we use both observatory data and the CM4 quiet time magnetic field model. In particular the CM4 improves our knowledge of the geomagnetic jerks over Antarctica through the study of the sign changes of the secular acceleration maps.