This week at Macquarie Island: 27 May 2016

Whilst never being able to compete with the continental stations, last Tuesday we had what, for us, was big snow.

The meteorological team like to call it ‘light to moderate snow’ but since it snowed from 0830 to ‘at least 2300’ (even Met have to go to bed some time), it was enough to give us a good coating of white from top to bottom. Being Macca, we had gale force winds to go with that for the afternoon, so it was definitely indoor job time.

The wind continued on Wednesday and was keen to take all the snow away as soon as possible so, when the wind dropped on Thursday morning, a few of us managed a quick lap up on the plateau to see what it was like covered in white.

The oldest continuously running project on Macquarie Island is the geomagnetic observatory, which started in April 1952 and is run by Geoscience Australia.

'Geomagnetism is the study of the Earth’s magnetic field, which allows navigation by compass, enables migratory species to find their way to and from breeding grounds, and protects the planet’s atmosphere from being diminished by the solar wind. The geomagnetic field is constantly changing. Dramatic changes because of solar activity can occur within seconds to hours, while subtle changes caused by the motion of molten fluid in Earth’s outer core some 3000 kilometres below the surface operate at time scales of thousands of years. Geomagnetic observatories monitor all these changes to gather information for navigation, oil and mineral exploration, and scientific research.' – Geoscience Australia

The observatory is a lot of little huts, and what look like pipes coming out of the ground, at the southern end of the station. There’s a 100 metre circle around them which is called the ‘mag zone’ and we’re not meant to have any metal in this area that could affect the readings. Given how thin the isthmus is, this isn’t totally achievable all the time, but we try our best.

Most of the equipment on Macquarie Island is automated, but approximately once a week Senior Communications Technical Officer Rob Bennett has to head down to the mag zone to do a set of ‘absolute’ readings as a quality control against the automated systems.

To do this he uses a declination-inclination magnetometer, which consists of a fluxgate magnetometer which has an output voltage proportional to the strength of the magnetic field component along its axis and a non-magnetic surveying theodolite; and a total-field-intensity magnetometer, which takes 8 automated readings at 10 second intervals.

Colin Robertson of the 1954 ANARE kindly donated a copy of his diary to the station, and from these we can see the type of equipment he was using in 1954 when he was stationed here as the geophysicist. The principle seems to still be the same, even if the equipment now feeds to computers and satellites.

Live data from Macquarie Island is available on the Geoscience Australia website.

Sunday was a glorious sunny morning and everyone was out to enjoy it. The king penguins and their chicks at the colony down by Gadget’s looked to be enjoying the sun-baking. A big change from the snow of a few days earlier.

One of the more ambitious ideas for influencing the landscape at Macquarie Island was to grow trees, and at the end of 1955 the planting began.

Station log 21/12/55 — 8th ANARE

'Transported and planted trees on Wireless Hill in later afternoon. 24 of various varieties grouped in sheltered area planted with or without lime and some in mineral, others in peat and some in mixed soils. Also planted a Chinese Juniper near huts. Repaired glass box for seedlings and planted lettuce seeds. Discovered ram and three ewes on Wireless Hill in sheltered gully so now have full count of sheep… All men very happy and in perfect harmony.'

But the trees didn’t thrive. By the following year:

Station log 3/8/57 – 9th ANARE

'Three-quarters of the trees planted last year have died and numbers of this years also. Although many trees are still alive, none seem to be growing'.

[Mentioned elsewhere in the station log are planted willow, birch, pine and alder trees, in three separate plantations — Wireless Hill, Camp Hill and Gadget Gully, none being promising.] 

Station log 1/9/57 – 9th ANARE

'The seedling trees are putting forth their buds, to spring forth their leaves in the summer, only to lose them again in the winter, and so on, ad infinitum. From a meteorological point of view, it is my firm conviction that trees will NEVER grow on Macquarie Island. If it were possible, these would be here now, and should have been for millenniums. The seed would have been transplanted from other islands in the feathers of birds, or stuck to mud on their feet. It is not the cold of winter we are up against… The difficulty arises from the lack of WARMTH in the summer… Macquarie Island is about 300 miles south of the tree line.'

And this view proved correct, as we are still completely tree-free.