Commissioning the new geomagnetic observatory
Geoscience Australia operates, with support from the Australian Antarctic Division, long established geomagnetic, seismic, and geodetic observatories on Macquarie Island. The geomagnetic observatory on Macquarie Island first began measuring the earth’s magnetic field in 1952 and has provided continuous monitoring to this day. At 70 years, this makes it the longest continuous data set of magnetic field data in the southern hemisphere.
Each week, the AAD comms technician (thanks Matt G (outgoing), Greg, and Craig) who has been trained in conducting observations in the absolute hut will measure the magnetic field using a magnetometer mounted on a theodolite. These weekly readings are necessary to calibrate the real-time instruments running in the variometer hut and keep data within specified tolerances as part of the International Real-time Magnetic Observatory Network (INTERMAGNET).
The primary reason for my visit to Macquarie Island is to commission the newly relocated geomagnetic observatory, constructed by the AAD trades team just to the west of Razorback gap as part of the Macquarie Island Modernisation Project. It is an incredible site to work in, with nearby seal harems, the occasional wandering king penguins, and a neighbouring gentoo colony. The work includes setting up a new declination inclination magnetometer, relocating instrumentation from the old variometer hut, training the summer comms guys in conducting absolute observations, and other miscellaneous work including instrument comparisons, determinations of azimuths, pier differences and gradient surveys. All this work is to ensure smooth continuity in data between the current and new observatory and continue the long legacy of geomagnetic data from Macquarie Island.
The geomagnetic data collected and delivered from Macquarie Island supports several activities including:
- Space weather monitoring:
- Macquarie Island occupies a strategically important location in a sparsely monitored part of the Earth, bridging the gap between the Australian mainland observatories and the Antarctic stations of Casey and Mawson. Magnetic field variations measured at this observatory are delivered to the Space Weather Forecasting Centre in near real-time to mitigate against the potential impacts of geomagnetic storms for Australia.
- Data from Macquarie Island provides valuable calibrated baselines for use in the Australian and International Geomagnetic Reference Field models (AGRF and IGRF) and is used widely for scientific research. Stakeholders depend on the AGRF to supply nautical and aeronautical charts used for compass-based navigation.
- The data from the Macquarie Island geomagnetic observatory is freely available through Geoscience Australia in near real-time and from data centres such as Intermagnet and the World Data Centre (WDC).
ARPANSA radionuclide monitoring station
Macquarie Island hosts a radionuclide monitoring station managed by the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA). This facility, codename AUP07, is one of 80 such stations around the globe whose function is to collect airborne particulates and to measure their radioactivity. This network is complemented by a global seismic, hydro-acoustic and infrasound network, all in support of the Comprehensive Nuclear-Test-Ban Treaty (CTBT) to which Australia is a ratified signatory. This Treaty was drafted in 1996 and it bans nuclear explosions by everyone, everywhere; above-ground, under water and underground.
The Macquarie Island CTBT station was installed in 2011. This facility is largely autonomous, requiring a daily filter change which are performed by the AAD communications technicians. The data from the collected samples are transmitted to the international Data Centre in Vienna for analysis.
This season, the Macquarie Island CTBT station is undergoing a major refurbishment and ARPANSA Engineer, Silvio, is on site carrying out significant preparatory and support work for this project. The AAD trades teams have built a brand-new facility and this refurb will see installation of new equipment to future-proof the AUp07 CTBT station for many more years. This significant modernisation project will be completed at the end of the summer season.
Matthew G (Geoscience Australia) and Silvio M (ARPANSA)