Ice Core Analyst
Barbara Smith
I have been the ice core analyst
with the
Australian Antarctic Division for over
six years. During that time I have been
to Antarctica twice to collect ice samples,
and am busily preparing for my next
trip in late December this year. There
are a wide range of activities in my job;
everything from expedition preparation
and participation through to ice analysis,
research and paper or report writing. So
what does it all involve and how did I
become the ‘Ice Queen’?
It was not my intention to become a glaciologist! I studied Applied Geology at the University of Technology, Sydney (UTS), and received my B.App.Sc. in 1991. After some time in the mining industry of Western Australia and the Hunter Valley of New South Wales I made a major decision to move into research. I went back to UTS as a tutor, and then as a full-time PhD student. I was fortunate enough to become involved in a project on the reefs of the southern Great Barrier Reef, looking at reef development history through lagoon sediment cores.
Most of my career to this point had involved looking at geological processes through information held in cores of rock or unconsolidated sediment, so when I saw a job as a glaciologist to work on ice cores I couldn’t believe my luck! Many people raise an eyebrow when I reveal this jump from reef to Antarctic science, thinking there is no continuity for me. There is, however, a direct link; the reef wouldn’t be there if it wasn’t for the warming period after the last ice age (about 10,000 years ago) when the sea level rose by 120 metres! These sorts of processes fascinate me, so I am very happy to be participating in research that addresses Earth’s Holocene history.
My two trips south so far have been the most exciting times of my life, partly because I have to pinch myself continuously that it’s all happening to ME, and partly because the scenery is so enthralling, and so completely different from anything else in my experience. Sadly, it is impossible to relay to those who have not been there what it feels like to be in Antarctica. You can show all the pictures and video clips you like, but they do not capture the ambience, the feeling of vastness, the cold, the camaraderie with your fellow expeditioners, or the feelings of trepidation at being in a place that could so easily take your life.
My first trip was in October 1998 to Davis Station where I was based for four and half months. It took three weeks to get to Davis via Casey aboard the Aurora Australis, and three weeks to get back via Macquarie Island. My field work was to collect fifteen 5m ice cores from an area to the east of Davis and up to 2000m elevation; a region known as Wilhelm II Land. We travelled everywhere in helicopters, which I might add were not heated! I worked with one other glaciologist, and two surveying PhD students. In turn, I helped these surveyors with their work on the Amery Ice Shelf where we camped for two weeks in polar pyramid tents and used skidoos and quads (4WD motor-bikes) to collect data from the Shelf. My second trip, in December 2001, was in complete contrast to the first. I went to Casey Station on a round-trip, i.e., I came home on the same voyage that took me there. While the ship was resupplying the station with people and provisions, four of us drove on to the ice of Law Dome, and spent three days digging a snow pit (to do snow sampling down its wall) and taking shallow snow cores before returning to the ship and going home. As is quite normal, however, the weather upset our plans. It is known as the ‘A’ (Antarctic) Factor. The Polar Bird, which was the other vessel being used that year, had been beset for about a month near Davis and didn’t look like it was going to get out by itself. It was decided that the Aurora Australis would go to its rescue! Quite a diversion, but one I enjoyed very much, particularly as we succeeded in our mission, and had a bonus glimpse of the area near Mawson. One of my favourite pastimes on the ship is to be up in the bow gazing out of the anchor holes looking at the sea ice as we push through it. The sound of the resonating steel hull as it scrapes through the ice is wonderful.
This year I am taking part in a joint project between the AAD and the University of Newcastle to contribute to the International Trans Antarctic Research Expeditions which look at climate change over the last 200 years. I am going to Casey Station aboard a Russian ice-breaker, the Vasiliy Golovnin, and will be away for ten weeks. This time I will be flown by Twin Otter aircraft from Casey to a site about 700 km to the southeast to drill a 100 m ice core with a mechanical drill and to dig some snow pits. We will then be relocated to another site closer to Casey to repeat the process. We expect to be in the field for about a month or so depending on the weather and how well the drilling goes. I will be the only woman in a party of six.
On a personal note it is relatively easy for me to spend several weeks away from home, as, apart from missing my partner and our pets, I have no other dependants. I am, however, looking forward to the introduction of air transport, to shorten the duration of our expeditions.
Ice core research
If you have ever heard of counting tree rings to look at seasonal variation then you are well on the road to understanding ice core analysis. The snow falls onto the Antarctic continent and generally remains frozen. The snow crystals are essentially a chemical sample of the atmosphere at the time the crystal formed, and so that information is kept in the ice layers and incorporated into the ice sheet. The chemistry of snow is different between the summer and winter seasons. This is due to various environmental factors such as the amount of light, air temperature, and the distance of the snow deposition site from the coast (which changes as sea ice expands and contracts from winter to summer). This seasonal difference in ice chemistry allows us to monitor the changes in atmospheric chemistry over various time scales; from months to thousands of years. In our case, where we have a 1200m core from Law Dome near Casey Station, we have ice that dates back 100,000 years - into the last ice age. This drill site has unusually high annual snow accumulation of about 1.5m, which means we can achieve very high resolution in our analysis. These layers are compressed and smeared out with depth (as the ice sheet in continually on the move downwards and sideways) so that one year of snow in the lower sections of the ice core is only represented by just a few millimetres.
This work is very much in progress and holds a lot of potential as a tool to help predict the nature of climate change, but before we can use it this way, we must first understand what has happened in the past. In geology we learned that ‘the present is the key to the past’, but in this case it’s more ‘the past is the key to the present’.