Geomagnetism and Paleomagnetism

The Italian Magnetic Network is composed of 114 repeat stations and its last complete measurement took place in the period 1999-2001, i.e. centred at epoch 2000. Mathematical models and maps were produced for declination, horizontal and vertical components, together with the total intensity of the geomagnetic field. By the end of 2005 the Magnetic Network measurement will be repeated again completely. To the Italian sites have been added also 11 other stations in Albania. Those were measured in 2004 with the collaboration of the Albanian Academy of Science and the University of Tirana. Together with this activity also another one dedicated to airports or heliports measurements has been undertaken. This kind of measurements has the objective to provide absolute magnetic knowledge of the magnetic declination in airports and heliport swinging roses where it is possible then to calibrate aircraft compasses.

Antarctic climate changes have been reconstructed from ice and sediment cores and numerical models (which also predict future changes). Major ice sheets first appeared 34 million years ago (Ma) and fluctuated throughout the Oligocene, with an overall cooling trend. Ice volume more than doubled at the Oligocene-Miocene boundary. Fluctuating Miocene temperatures peaked at 17–14 Ma, followed by dramatic cooling. Cooling continued through the Pliocene and Pleistocene, with another major glacial expansion at 3–2 Ma. Several interacting drivers control Antarctic climate. On timescales of 10,000–100,000 years, insolation varies with orbital cycles, causing periodic climate variations. Opening of Southern Ocean gateways produced a circumpolar current that thermally isolated Antarctica. Declining atmospheric CO 2 triggered Cenozoic glaciation. Antarctic glaciations affect global climate by lowering sea level, intensifying atmospheric circulation, and increasing planetary albedo. Ice sheets interact with ocean water, forming water masses that play a key role in global ocean circulation.