Scientist: Dr Andrew Smith, Physicist and Principal Research Scientist at ANSTO
School: Caringbah High School
Physicist Dr Andrew Smith is a time traveller. Well, he doesn’t have an actual time machine, but as he drills into polar ice sheets he can recover samples from the Earth’s past. The deeper he drills, the further back in time he goes. The work he's doing studying pockets of air trapped in ice is helping scientists to understand the Earth's past climate.
Andrew has travelled to some of the coldest places on earth to conduct his studies, including trips to Antarctica. His latest field trip to Greenland to study carbon-14 (14C or radiocarbon) produced by cosmic rays in the compacting snow (the 'firn') of ice sheets is helping scientists to better interpret the 14C signal in methane (CH4), an important greenhouse gas.
He spoke with students at Caringbah High School about his research and life in Greenland. Listen to his talk with the students or read the transcript below.
Transcript
 | Michael: How do scientists date the materials from the ice cores and what sort of processes are used? |
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Andrew: Do I understand you properly; how to date the ice core?
An Ice core contains not just ice it also contains air. The work we’re doing here [in Greenland] involves studying some of the chemicals that are trapped in the ice, and also most importantly, studying the composition of the air that is ultimately trapped as bubbles in the ice… at different ages.
Firstly, let me answer how you date an ice core. The main way you do it is you use water isotopes. Water is composed of hydrogen and oxygen… H2O.
Just so you know, an isotope… the elements… have unique chemical characteristics because of the number of protons they have in their nucleus. As well as protons, there are neutrons in the nucleus and it turns out that oxygen, for example, can have eight neutrons, it always has eight protons… but it can also have eight neutrons, or nine neutrons. It can even have ten neutrons. That show its atomic mass and we call that Oxygen16 because it has a mass of sixteen.
So most oxygen has a mass of 16, but there other isotopes of oxygen that are heavier such as oxygen 17 and eighteen; same as hydrogen, which can have the atomic mass of one, two or three. All these isotopes have the same chemical behaviour, but they do behave a little bit differently physically, so they evaporate differently. For example, the light isotopes (water composes of light isotopes) evaporate more readily; compared to water comprised of the heavier isotopes.
When the water condenses the heavier isotopes seem to condense before the lighter ones. And, so what happens is because of seasonal temperatures the snow that falls in places like Antarctica and Greenland, has a different isotope ratio - some of the water is heavier some of the water is lighter.
The principle way of dating ice is to measure the variation of those isotopes along the length of the ice core and then you can pick them out, just like with tree rings where you can pick out growth rings - you can see them. You can also use radiologic equipment. You can detect these rings, if you like, in the ice. That gives you the ability to actually date the ice.
There are all sorts of other signals too. There are volcanic eruptions, for example Mount Tambora (on the island of Sumbawa, Indonesia), Mount St Helen… some of these big volcanic eruptions put down [sic] salt over-layers in the ice that can be detected.
There are a number of other chemical signals that have a seasonal characteristic and that allows you to actually count-back the years from the surface. So that allows you to date the ice… but dating the actual air in the ice is a little more complex.
I don’t want to get to elaborate, but basically as the snow falls in polar regions… it doesn’t melt, of course, it continues to accumulate and as it accumulates it gets compressed and typically at about 80- 100m below the surface so its gets so compressed that it turns into ice. Until that happens there are open channels in between the snowflakes that contain air and that air is still in contact with the atmosphere, although through very, very complicated paths. And as you can imagine for 80 meters of what is called firn… the compressed ice is called firn ice and that is one of the principle things we are doing here.
We are drilling down into the firn core into the other 80m and then we’re plugging a hole with an inflatable bladder and we’re sucking out the air from those little spaces between the compacting snowflakes.
And that allows us to access air which is very old but the air is actually younger than the ice that contains it because of this disposal process. Today, you might be interested to know I was breathing air from 1980. I was actually inhaling air that was on earth 30 years ago that we sucked it out from deep beneath the ice surface; 74m beneath the ice surface .
| Jimmy: I have a few questions. One was how far back can you date the ice samples does it get less accurate the further down you go, or is it just how deep you can actually drill? |  |
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Andrew: That’s a really good question and the answer is ‘yes’, it does get less accurate the further back you go. In a sense, we’re operating a time machine here. By drilling into the ice, and the further we drill, the further back in time we go.
The further back in time the more difficult it is to date. When you have very great depths in the ice the bubbles and salts actually disappear and the gas is still there but turns into what is called a claprate and when you get to that stage it is very difficult to date the ice.
One of the things we are able to do here is to see whether it is possible to use radio carbon - carbon 14 that dates ice where it is not possible to count any more readings in the ice core.
But having said that, the eldest ice core record so far come from Antarctica - from a place called Dome Concordia (Dome C) - and that ice core was drilled to a depth of 3200m. Now they been able to date by using an instrument you would not be able to understand, but that ice contains a record of the Earth’s atmosphere that goes back 8050 years before Christ. That so far is the biggest record.
The Australian Antarctic division is now doing an expedition this coming season where they are hoping they might be able to attain a record of 1 million years. The dating of that will be a digital hub.
| Jimmy: I have another question that’s just a bit more about being in Greenland. What’s the weather like and temperature? And also. if you’re to go further north, could you see the northern lights? | |
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Andrew: Oh, yes, the northern lights the aurora borealis – which in the southern skies it’s called the Aurora Australis, and the Australian sea ship it is named after.
I would love to see the Northern and Southern lights but I have never had the opportunity and this is exactly the wrong time to be here to see the northern lights because it’s daytime and the sun doesn’t really go down here. It’s pretty much perpetual daylight and so although the aurora borealis could be indeed happening if the sun was active enough I wouldn’t be able to see it.
I would have to come back in winter but of course in winter it is much colder.
Trust me, the temperature is nice but we have had some bad weather over the last two weeks. But the last couple of days have been much nicer and tonight there is hardly any wind which is nice. But the temperature is about -27 degrees Celsius. But it is not as cold as the first night we arrived, and the first night we had to sleep in a tent here, because we are all sleeping in tents here, it was -38 degrees Celsius. That is seriously cold.
 | James: My question is are there lightning storms in the Artic, and if so, what happens to the ice if it is struck by lightning? |
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Andrew: That is a very interesting question. I’m not sure. I think the answer really is that there are not really lightning storms.
It’s possible there could be, but it is certainly not something that is common because to have a lightning storm you need the right kind of vindictive moist clouds, and you need to have the strength to carry ultra-paths that carry the water particles. That’s where they can acquire an electric charge and they can charge the water at the top and bottom of the cloud that causes huge lightning bolts.
Here in Greenland, it is too cold for that to happen. It’s very dry here… you have to understand… it’s quite a paradoxical place in Antarctica.
The ice sheet here is about 3km thick, on average and it contains 70 per cent of the world’s fresh water, yet it is the driest continent on earth. The difference is of course it is so cold the little bit of water that does falls out of the sky doesn’t melt it or run away just accumulates.
Over at least a million years that water has been accumulating but it hasn’t been accumulating through cumbersomes. So, lighting is a rarity.
| James: Is all your research funded by ANSTO? |
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Andrew: The research? In this case it isn’t funded by ANSTO at all really, other than that ANSTO was paying for my salary.
This research is funded by the National Science Foundation (NSF), which is the main scientific funding agency in America. I’ve been collaborating with the lead scientist here Dr Vasilii Petrenko in projects in Antarctica now for at least 10 years.
And he put in a request to the NSF to undertake this project and this is just the first year of a 5 year project and he put in a request for me to participate as well. So ANSTO is not funding this, they’re paying for my salary while I'm here, and of course… they will pay for the research I will be doing on ice cores that I will be taking back to Australia.
That’s another interesting thing. I have big boxes that are two-thirds packed with ice cores. I have the interesting task now of bringing them from almost exactly the other side of the planet back to Australia, without them melting. Wish me luck!
| Lachlan: I was just wondering what exactly led to you being where you are and what science did you have to study and how long did it take to be where you are? |  |
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Andrew: Ok… I’ve been doing science for many years. I have been working with ANSTO (the Australian Nuclear Science Technology Organisation) since 1989, so what’s that - 24 years.
I’m almost coming up to my 25th anniversary. I hope they give me a nice gold watch.
Before that I went to high school obviously and went to university and did an honours degree in physics. I worked for one of the research groups at the University of New South Wales for about 4 years during that time I built an ion accelerator - small particles accelerator. Then I did my PhD and got my doctorate, so I’m now Dr Smith, as a result… and shortly after that I started work at ANSTO. I started university in 1974 which is 39 years ago.
When I first started working at ANSTO, my main job was to develop a 10m volt accelerator we purchased from a university in the [United] States. I’m a physicist. I’m not an atmospheric scientist and I’m not a climate scientist. I’m a physicist. I work with particle accelerators, and in particular, I work in the field of accelerator mass spectrometry. Actually, when people ask me what I do for a job, the easiest answer is that I count atoms for a living, which is true, but it doesn’t mean very much to anybody.
The atoms that I count are specialised ones which are cosmogenic radio nuclei’s, so they’re radio isotopes that are produced in the atmosphere and in the surface of the earth and ice sheets.
They are caused rocks with cosmic radiation that have come from the distant reaches of the universe and are very energetic particles - much more energetic than those particles that would be used in the Large Hadron Collider, for example.
One of those radio nuclei’s for example is carbon 14. Our accelerator at ANSTO, at Lucas Heights, is a very distinct machine that allows us to position the ratio of this special mini isotope, which has point of 14 to the normal of 99% carbon as an atomic mass of 12 and we can measure that 14 to 12 ratio to one part to the 16 by literally counting the atoms.
The samples that we take from here in Greenland are then going on a long journey. They’re going to go first to the United States.
The gas samples, then carbon gases will then be extracted from the carbon monoxide, methane and the carbon dioxide and then ultimately it will arrive at ANSTO where it will be converted to graphite and will be put into my accelerator.
But the amount of carbon that we will be dealing with is about 21grams, which are very small amounts… microscopic amounts of carbon. And yet, the accelerator at ANSTO has the ability to measure that 14 to 12 ratio to one part of the 16, which is one of only a few laboratories in the world that can do it.
So that is my connection with this research that is going on here. There are a lot of different things we are getting… a lot of different samples for a lot of people for a lot of different reasons.
But one of the main ones is to understand how this radiocarbon is produced in the ice and where it ends up in the air around the ice so we can study the partial production of methane. So it is basically climate research but it is kind of a complicated connection. I hope that answers your question.
| Tom: My question is what kind of equipment did you have to bring and how was it transported? |
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Andrew: Ok, there is an amazing amount of equipment. Luckily I didn’t have to worry too much about this as this is an American based program. The way it works is that there is the Air National Guards in the US who are contracted by a company called CH2M (CH2M HILL Polar Services) - a polar research organisation that works within the NSF.
You probably read my blog about the ski trip crawlier that crawl up you? So those guys did a lot of organising for stuff like food and generators, and tents.
We are completely self-contained. Our camp is set up 10km away from the main research station from summit Greenland. Incidentally we are 3200m above sea level, so you would notice the lack of oxygen.
The air pressure is so much less here than sea level in which water does not boil at 100 degrees Celsius; it boils at 89 degree Celsius, so it takes longer for cooking for instance. But for a camp of this kind you need diverse infrastructure.
You need tents, the weather port, which is like a specialised tent, is our living area and that has our packing area. There is a big installation, basically a shipping container, built to accommodate our science laboratory. You also need drums - 200L drums of fuel or petrol, and diesel. You need special stoves to warm the heating area. There’s a lot.
I am actually sitting in a tent that is called an artic oven which is a big tent. In order to sit comfortably and talk to you remember it is -27 degrees I have a little generator that I have put some distance away from the tent so I am not bothered by the noise and have run an extension cord in here with a heater so I’m fairly comfortable in here at the moment.
But all the food and supplies and everything… there is a lot of stuff involved just located around my tent. At the moment, I see extension cords, drums of oil, ships of word, canes. One of these things you have to bring is lots of cane. Believe it or not, we use bamboo poles to mark out areas with flags, clean areas and areas where we have to mine the snow. All our drinking water comes from melted snow, so you know we have a clean area and every now and then a couple of guys go out with a big bucket, which is known as the clean snow bucket, and fill it full with snow and bring it back inside the weather port and put it in a big pot on top of the stove to melt so we have drinking water.
So that is basically just to survive and to be able to work. On top of that, you have the scientific gear. Now I have a science sled. These are things that help carry ring dells electrometers that allow us to measure methane and carbon dioxide concentrations. You have to a residual and an RGD device that allows us to measure carbon monoxide concentrations. They’ve got crates and crates of sampling vessels of one kind or another. All the wiring and the bottles of standard gases that run through this machine in between taking samples from a firn. There is a lot of stuff.
Like I said I didn’t have to worry about that too much because I wasn’t leading this expedition.
From my point of view I did have to worry about getting my ice cores back to Australia. That for example involved getting 12 special boxes manufactured in The States and sent to the Air National Guard’s base in Albany.
I had to get 18 boxes of detected gel packs diluted to the National Guards base; I had to get vinyl covers made for my boxes, which were also sent there and various other things. Luckily, it all came together. The first time I laid eyes on this stuff was when I was up here at the substation so the logistics is extraordinary to lead an expedition like this.
I don’t know how much this one actually cost but I can tell you that for a smaller expedition that I had in Antarctica where I was the leader back in 2005, where we were camped, it cost about $1.5 million, I believe just for the logistics and the transport of equipment that was required.
So it was expensive. So that’s why we want to get as much science out of it as we can and as much public outreach as we can so talk to people like you guys and hopefully getting you interested in science and and away from this idea we all wear white coats, that couldn’t be much further from the truth… well, most of the time.Science it’s quite often an adventure of things and I guess I’m having a pretty good adventurer at the moment.
| Jimmy: I’m back to ask questions for few people who were not able to attend. This one is on behalf of Courtney, who wants to know if you enjoy working in science? | |
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Andrew: I do enjoy working in science. I guess I'm kind of lucky. I’ve always been interested in science. When I was in primary school, my primary school teacher must have recognized this because she used to call me a professor so I’ve never had to think terribly hard about what I want to do. I have always had a passionate interest in how things work and in science.
| Jimmy: This next one is just for myself. When you say ‘the summit of Greenland’, is that right up north, or is it the highest point? | |
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Andrew: The summit of Greenland is the highest point; therefore it is the coldest point. It’s not the furthest north.
I just looked at the GPS today I was marking the position of our ice hole and from memory we are about 75 degrees north, so 15 degrees away from the North Pole.
We are well-and-truly inside the Arctic Circle. If you have a look on the internet or in a textbook you will see above the Arctic Circle. That means at certain times of the year in Summer - the solar equinox - the sun never goes below the horizon when your that far north.
Then you have the Antarctic Circle. Law Dome where I do most of my work is just on the other side of the Antarctic Circle so once again the Southern Hemisphere equinox never goes below the horizon.
This is what defines the Arctic Circle. The Arctic Circle from memory is 66 degrees from north and south. We’re e not as far north as you can go, but we’re about as high as you can go in the world. I don’t think you can go much higher than this. As I said before we’re over 10, 623 km and we’re sufficiently higher than the air pressure which is low enough for the water to boil at 89oC degrees not 100 oC degrees.
| Jimmy: How many people are at the camp? | |
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Andrew: There are a lot of people here probably more than what we need. There are 9 of us altogether, two of them are students who are here for training purposes.
Part of the funding for this project was to involve students and train the next generation of Polar Scientists. We could work with 6-7 people but we would be working much harder.
The names of the nine people who are involved in the project include:
- The expedition Leader is Dr Vasilii Petrenko from the University of Rochester
- Benjamin Hmiel, 1st year Post Graduate Student, Lindsey Davidge, Graduate from the University of Rochester
- Dr Christo Buizert, Postdoctoral fellow from the Oregon State University
- Second year postgraduate student from Oregon State University named Jon Edwards
- Myself (Andrew Smith) from ANSTO
- Three drillers from the Ice Drilling and Development Organisation (IDDO), which is an American company. The names of the drillers are: Tanner Kuhl, Louise Albershardt and Mike Jayrad. They’re responsible for all ice drilling operations.
We’re not doing the ice drilling they are doing it for us, we take the firn and ice samples from that.
 | Judy: Can you tell us what a typical what a day might be for you when you’re working in Greenland? |
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Andrew: This really depends on the weather. A typical day will involve me waking up at 7am after having a rather restless sleep. I crawl out of my sleeping bag and change my socks;taking my bed socks off and placing thick socks on. I make sure I put my over pants on, put warm clothing on, and put my big glacier boots on.
Once I put the glacier boots on, I crawl out of my tent with my pee bottle in my hand. One needs to go to the toilet at night and you don’t want to go out when its -38 degrees celcius.
The first thing you need to do is empty the pee bottle otherwise it will freeze and you will have trouble the next night.
Then I find my way into the Weather Port where I will have breakfast and make up some milk, as we have powdered milk. I make a bowl of cereal and some toast on top of the stove.
Then I will put the rest of my gear on such as my big jacket and if it’s a bad day I will put my balaclava, goggles, hat and my gloves on. Then I will go up to the drilling site, where they would have already started drilling and hopefully I arrive about the time they will pull up an ice core. I would then take that ice core and measure it for length and make something interesting sketches of it and accumulate pieces of ice core enough to make a 1 metre long section in a bag. I will then bag it and stamp my feet around and wave my arms around to try and keep warm until the next ice core comes up.
When there’s a chance when the drilling stops and it’s time to do the firn air sample, the drillers carefully take out the drill and make sure it doesn’t get covered in snow and stays nice and cold. Then the firn air samples are put down a long ladder that is a 5 metre leakage ladder and lowered down to the base of the hole we just drilled and then from inside the ice sled.
They’ve got all their pumps and valves and equipment and whatever, and that ladder delicately seals the hole from the atmosphere above. They then start sucking the air out from beneath. I then work out when I'm able sit down to write my blog, organise my photos and do various things.
When I’m at Summit station I have to stay in touch with ANSTO and give some work. I would then go back to the drilling site and there would be an ice core. The drillers would pull up the ice core block put it on a sled and drag it 100 metres to the ice cave where the temperatures are mostly -30 degrees celcius.
When the weather is bad you get what is called a whiz trail behind any structure, the driving snow builds up to an amazing extent.
We have whiz trails behind buildings that are over 1 metre high and in front of the buildings where the wind is striking them you get what is called a wind stellar, so it gets taken away. The whole site is transformed and it makes it very difficult to get around the site. To get into your tents you have to dig your way up and in bad weather I have to literally dig my way out of the tent.
It hasn’t been terrible as there hasn’t been more than 20-30cm of snow, but you still have to remove it before you get out so there is a lot of work involved in clearing up the site with snow shovels. Before we start drilling each morning for the last couple of weeks, the first order of the day is to man the snow shovels and shovel out cubic metres of snow from the drilling area and dig out the equipment that got buried the night before.
There’s all the daily tasks such as melting snow, cooking food and meals. Before I rang you I had to do the washing up in whichy ou have to do these domestic tasks, the simple business of staying alive and healthy; and keeping the place in an organised shape.
We’ve got a number of generators we have 5Kva and a 6Kva which basically run all the time and of course we have to fill the fuel.
That sounds simple to do but it isn’t so simple under these conditions as the fuel pumps are buried under the snow and they are a long way from where the generators are.
To get the fuel drums out of the snow you have to man handle the fuel drums and put them onto the sled.
The next step is you have to transport the drum up to the generator and then you have to manually operate the pump to pump the fuel into the generator. This process takes a lot of time and effort and of course the worse the weather is the harder it is to do.
Sometimes you can’t physically do the things you need to do with gloves on, so you have to take the gloves off. Of course when the temperature is cold and the wind is blowing, your hands can’t stay in the cold for terribly long. You have to do it in stages when your hands get too cold you have to put your gloves back on and wait til they warm up and start again.
I had a lot of work to do with preparing the ice core boxes to ship them back to Australia. The preparation included letters for customs and quarantine people, finalising the shipping addresses and entering the details into the cargo tracking system used by the Air National Guards.
It’s quite good at the end of the day when you crawl into your sleeping bag with your hot water bottle to warm your toes up and go to sleep.
| Judy: I think you earned your rest! |
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Andrew: Well that’s going to be coming shortly. One of the most amazing things I found here is all the equipment fails in the cold. I was very disappointed when my Swiss watch stopped working, my telephone and my computer in -38 degrees celcius.
One thing that does work amazingly well in the cold is my iPad. When I go to bed at night I snuggle into my sleeping bag and read Higgins on my iPad, which I thoroughly enjoy. I have been watching movies such as the Hobbit and Great Expectations which I have been going to sleep to at night.
Published: 28/06/2013