Australia: Australia’s magnetic field is weakening and the relationship between magnetic north and true north is continuing to vary, according to the analysis by Geoscience Australia of observations from geomagnetic stations on the Australian mainland and Antarctica. However, the observations reveal that the rate of change in the magnetic north direction differs significantly between northern Australia where it has decreased by one quarter of a degree over 10 years and at Mawson in Antarctica where it has decreased by one-and-a-half degrees in the same period.
“These variations can be particularly significant for people using magnetic directions on old maps for navigation,” said Dr Adrian Hitchman, Geoscience Australia scientist.
“By applying an old compass direction found on the map, people moving through the terrain could find themselves several kilometres off course over a journey of a few tens of kilometres,” he said.
“Because Earth’s magnetic field is constantly changing it is important to use the latest geomagnetic data to confirm its direction for navigation,” Dr Hitchman added.
Geoscience Australia uses a network of 11 geomagnetic observatories in Australia, the sub-Antarctic and the Australian Antarctic Territory to monitor the changing magnetic field in the region. The data are retrieved in near real-time and distributed to Australian and international clients, including the International Real-time Magnetic Observatory Network (INTERMAGNET) to become part of the data set representing the magnetic activity of the entire planet.