Measuring the sea ice thickness
Measurements will be taken by an electro-magnetic device called the EM Bird slung on a cable 30 metres below the airship. The device will be lowered once the craft is airborne. The pilot must fly at speeds between 50 and 70 kph and maintain an altitude of 50 metres so that the EM Bird is always 20 metres above the sea ice. Measurements are instantaneous and are fed into the on-board computer in real time. By the end of the expedition, we will have flown about 10,000 km over the sea ice from one side of the Arctic Ocean to the other, and we will have gathered significant reference data on the thickness of the sea ice at the end of winter 2008.
Measuring the Earth’s magnetic field
The measurements will be taken by a magnemometer supplied by the CEA/Leti. Measurement of the magnetic field in the area around the pole helps to locate the magnetic poles but also to study the external sources disrupting the magnetic field and to map the magnetic anomalies.
A number of airborne observation campaigns have already been carried out on this theme, and special satellites have been launched and ground-level observatories set up. However, the Earth's main magnetic field is changeable and the position of the poles can move rapidly, and as satellites are unable to fly over the poles the only way to measure accurately the magnetic field in the Arctic is to carry out on-site magnetic surveys. The Total Pole Airship expedition can not only do this, but it provides an even more interesting opportunity to carry out a survey in a star pattern with the Geographic North Pole as its centre. This should provide new profiles to enhance the existing map of the magnetic anomalies in the region.
This updated map will be integrated into the World Digital Magnetic Anomaly Map that is currently being drafted.