- Ionospheric Observatories
- Geomagnetic Observatories
- Seafloor Multidisciplinary Observatories
- Italian Magnetic Network
- 120 repeat stations of the Italian Magnetic Network
- National Magnetic Cartography
- Normal Fields
- Repeat stations
- Electromagnetic Surveys
- Data Bases
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Italian Magnetic Network
The role of magnetic networks is, in the first place, to allow the accomplishment of a magnetic cartography in which geomagnetic field elements, as expressed by their values and their time variation, are reported on a map. Starting from the beginning of 1980, Istituto Nazionale di Geofisica e Vulcanologia (INGV) has systematically undertaken the task of measuring the Earth’s magnetic field in Italy.
At present, the Italian Magnetic Network consists of 120 points called repeat stations uniformly distributed on the national territory where measurements of the elements of the geomagnetic field are regularly repeated every 5 years with the aim to determine:
- the spatial variation of the geomagnetic field with the publication (in collaboration with Military Geographic Institute of Florence) of the geomagnetic field element maps for the various epochs of measure;
- the values of the coefficients of a second order (in latitude and longitude) polynomial through which the main field (with origin in the Earth’s core) is represented;
- the spatial features, generally on an area exceeding the national boundaries of the temporal variation of the geomagnetic field, named secular variation, by means of the exchange of the Italian data with the other countries (in Europe operates the Mag.Net.E. Organization, acronym of Magnetic Network in Europe).
The characteristics of a national magnetic network, as for instance the average distance between repeat stations, reflects the need to represent, accurately, the spatial variation and the secular variation of the magnetic field. In Italy, both for tradition and to preserve a detail that taking into account the peculiar geometry of our peninsula and islands, a grid of about 120 points, called first order repeat stations and with an average spacing around 55 km, is in operation. It results an average density of repeat stations of around 1 station on 2800 km2. Such stations density can be considered high in comparison to that of the other European magnetic networks, nevertheless the number and the distribution of the stations is also finalized to deepen several scientific aspects, such as the geodynamical evolution of the Mediterranean sea.