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We’re All Going on A Summer Not-Holiday: Part 2

Thursday, November 16th, 2017

I promised a follow-up post on what we actually did on fieldwork upon our return, so, here goes. In this post I’ll focus on the science; in a subsequent one, I’ll talk a bit more generally about the wider fieldwork experience.

First thing I will say is that from a scientific point of view, the fieldwork was a roaring success. We achieved all our objectives, despite arriving four days late (more on that in the next post). We set up and used several different instruments, which I’ll explain a bit more about below.

The first instrument, and the one I ended up being responsible for was the radar interferometer, which we set up to observe the calving front. To explain what a radar interferometer is: the first part, radar, is fairly straightforward. We all know what a radar is. It’s that thing with the glowing green screen that goes ‘beep’ and shows a dot as the enemy aircraft/tank/monster/etc. is detected by it in every action movie ever. Obviously, however, a dot showing there’s a calving front there isn’t terribly useful for us. This is where the second part comes in, the interferometer. Interferometry is the use of multiple discontinuous small receivers to crate a virtual massive receiver, which gives you much better resolution, and, critically, the ability to get a 2D picture of the target. It’s used a lot in astronomy – rather than building one very large telescope, you build several smaller telescopes and space them out a bit, giving you the same result (with the application of a bit of maths and computing power) for much less effort. Our interferometer had a baseline (the distance between the receiving antennae) of only about 15 cm, but it was enough for it to produce very detailed 2D scans of the entire calving front every three minutes, for three weeks. Continuously. That’s a lot of data, which we can use to study the processes behind calving, as well as the behaviour of the ice mélange immediately in front of the glacier, once it’s all been processed.

The radar interferometer, overlooking Store Glacier. The top antenna (the horizontal bars) transmitted; the two lower ones received.

Our second big instrument, as such, was the drones. Six of these were brought along, and, after a few initial technical issues, they worked almost flawlessly, making several successful flights at the calving front and at the site on the ice, 30 km inland. Despite every landing being essentially a tenuously-controlled crash. The drones were fitted with a digital camera, and took hundreds of overlapping photos of their target areas. We hope this will allow us to track very small changes in the ice surface between flights, but we’ll need to process more of the data to see how successful that is.

Tinkering with a drone at the calving front.

The third major group of instruments we set up was the time-lapse cameras. These are, again, fairly standard digital cameras, this time set up on tripods overlooking the calving front. We set up ten of these; four on the south side of the glacier terminus; six on the north side. These, ideally, will each take a photo of the calving front every five minutes for the next five years. Hopefully, they won’t break too badly in the meantime. Again, the array of overlapping photos should allow us to track terminus changes and calving processes over the longer term, which will prove useful in detecting trends and seeing how representative the data gathered this summer are.

And tinkering with a time-lapse camera….

The final set of instruments we used were the GPS stations. Four of these were set up at the inland site to allow us to track ice velocity (speed and direction) for the next few years (until they eventually break!), which will be useful in complementing the other datasets, as well as providing long-term information on the health of the glacier.

A very low-tech GPS station at the calving front. The inland ones were a bit more sophisticated.

We now have several terabytes of data (1 TB = 1000 GB = 1,000,000 MB) to process. That’s our work all sorted for the next few months….

And, to finish with, here’s a couple of videos of science in action: launching and landing a drone. Ignore what appears to be the giant space laser in the launching video – it’s just the Sun.

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We’re All Going on A Summer Not-Holiday: Part 1

Saturday, May 27th, 2017

This blog post is written by PhD student Samuel Cook

Five of us from the Scott Polar Research Institute – me, Tom, TJ (all PhD students), Antonio (a postdoctoral researcher) and Poul (our supervisor) – are going to be spending the entirety of July doing fieldwork in Greenland. Specifically, at Store Glacier, about halfway up the west coast of Greenland. We’ll be joined by researchers from other institutions and will be conducting a variety of scientific work – such as setting up time-lapse cameras at the calving front (i.e. the end of the glacier where ice falls off into the fjord), using drones to gather improved data on the glacier’s surface elevation and velocity, and radar measurements of ice thickness and basal properties – at several different locations on the glacier, up to 60 km into the interior of the ice sheet.

The location of Store Glacier (inset). The big green thing is the domain I use in my modelling work.

The location of Store Glacier (inset). The big green thing is the domain I use in my modelling work.

This presents several challenges. To start with, a logistical one: getting that many people and all the things they need to survive and use (food, tents, scientific equipment, clothes, etc….) to somewhere that could charitably be described as the middle of nowhere isn’t simple. We have to drive van loads of the bulkier stuff over to Aalborg in Denmark so that that can be shipped to Greenland, but this has to be done a few weeks in advance of our departure (June 27th) to make sure it arrives before we do. To get to Greenland ourselves, we have to fly via Copenhagen (Greenland being Danish, flying from Denmark is the easiest route), then on to Greenland. We then have to take a couple of internal flights within Greenland and a couple of helicopter journeys to get to the vicinity of Store. All this has to be done with us carrying all our personal kit. Such fun. And there’s all the paperwork to fill in to satisfy EU, British and Greenlandic customs regulations. It just gets better.

We also have to buy and test all the equipment, as well as buying all our own personal gear. This is a) expensive, b) complicated and c) tiring. It turns out two days of putting up and taking down a succession of tents to check for tears is hard work. On the plus side, they all seem to be intact. Unlike my fingers. I’ve also spent a gratuitously-large amount of money on buying all sorts of outdoorsy equipment to ensure I have enough clothing for a month. And so I don’t die of exposure. Or mosquitoes. There are going to be a lot of mosquitoes. You can’t catch anything from them, but the bites are unpleasant enough anyway.

Antonio, TJ, Tom and I setting up the biggest of the tents.

(Left to right) Antonio, TJ, Tom and I setting up the biggest of the tents.

Finally, there’s also a huge amount of university admin to wade through, funding to be applied for and so on. All of which also has to be done well in advance, and not forgetting the need to actually plan what we’re doing once we’re in the field, to make sure we don’t leave anything vital behind. The group has a lot of spreadsheets on the go, to put it mildly.

So, in terms of all the necessary preparatory work, it’s pretty safe to say that glaciological fieldwork is a long way from being a straightforward experience. Once we’re back at the end of July, I’ll write another post about the actual fieldwork. Watch this space…

Sounding out the Antarctic

Wednesday, November 23rd, 2016

This blog post was written by Grace Atkinson, a local student who came to see us in the Museum and asked if there was anything she could do. We gave her a research project, and this blog post is the outcome.

As an International Baccalaureate student with a keen interest in both geography and the Antarctic I decided to contact the Polar Museum to see if there was a project I could do outside of my studies to enhance my geographical knowledge as I am planning to study Geography at University. After looking at the exhibits I thought a blog post about radio-echo sounding in the Antarctic would be an engaging topic to research.

My aim is to increase people’s awareness of the different techniques used by scientists in the Antarctic to collect data from the ice sheets as the study of ice is becoming increasingly important; its thickness is useful in determining the impacts of climate change. Radio-echo sounding is a geophysical technique which investigates the thickness of glaciers and ice sheets, this becoming crucial within the study of glaciology. Before radio echo sounding was invented by the Scott Polar Research Institute in the 1960s, scientists such as Amory Waite, used radio to measure ice thickness however this method wasn’t widely known. Radar became more popular after an incident involving a WW11 Allied aircraft which when flying across Greenland crashed into the ice due to miscalculations with their radar altimeters. The accident caused increased interest in using the radar for experiments that measure ice sheet thickness in the Arctic.

Oliver Shepard stands on snow holding ice core drill during the Transglobe Expedition 1979-82.

There are lots of ways to study ice. In this picture Oliver Shepard stands on snow holding ice core drill during the Transglobe Expedition 1979-82.

The technique of radio-echo sounding since being developed in the 1960s is now used by a variety of institutes such as the US National Science Foundation to investigate and map the ice covered terrain in the Antarctic. As water and ice are transparent, low frequency electro magnetic waves can be used in the Antarctic to obtain the information and this method is accurate which is why it is used in other scientific investigations, for example marine acoustic sounding. There are echo pulses which penetrate the ice sheets enabling scientists to receive and analyse the data. These pulses are particularly useful for researchers studying the dynamics of ice sheets and their internal ice structure in sub-glacial regions. The radio echo sounding machine has two crucial components, these being the transmitter which sends out the echo pulses, and the receiver which records the strength of waves and the time it takes for waves to bounce back.

Traditional measurements of sea ice thickness are through drill holes which are effective at giving a good overview of ice thickness in extensive areas, however, the use of electromagnetism in radio echo sounding is much more accurate and reliable by comparison. In addition to this, one of the biggest advantages of radio echo sounding in the drilling of holes is its speed.

The invention of radio echo sounding has been influential and the gateway to the development of more recent methods of measuring sea ice thickness, for example the satellite altimetry which relies on the use of a radar pulse. However, there are limitations to the measurements as the laser only collects data in cloud-free conditions.

After researching the use of radio echo sounding in the Antarctic regions I believe it has proven to be the technology of major interest and importance due to its significance in scientific development such as the discovery of subglacial lakes in Antarctica.

Read about some of the work carried out by scientists at SPRI in recent years here.

British Antarctic Oral History Project

Friday, November 27th, 2015

A fascinating oral history project about the British work in Antarctica over the last few decades has just launched to the public. The project is the result of a collaboration between UK Antarctic Heritage Trust, British Antarctic Survey, BAS Club and Scott Polar Research Institute, and aims to “capture and preserve the recollections and memories of those extraordinarily dedicated individuals who have worked in Antarctica, with a particular focus on those who worked for, or closely with BAS and its predecessors, Operation Tabarin, 1943-45 and Falkland Islands Dependencies Survey (FIDS), 1945-61”.

So far, over 280 interviews have been recorded, of which 51 are currently available on the project website. One of the interviews records ex-BAS employee Ben Hodges talking movingly about his dog team and the emotional bond that he felt with them. Earlier in the interview, Ben had described what happened when an entire team of dogs fell into a hidden crevasse, and he had to climb down single-handed to haul them out. In this clip, he explains that the dogs were more than just a useful resource to be exploited:

“They had to be rescued whether I had to carry them down the glacier one at a time … They are friends, and companions. You don’t desert them. If there was a man in a crevasse, ten feet away from the crevasse that the dogs were in, I would have to pay attention to the man. But I would be on tenterhooks about the dogs. I would have to get the dogs back.”

 

Ben’s interview, including a full transcript, is available for streaming or download here.

In another clip, John Huckle reflects on the differences faced by modern polar scientists and “old-timers”. Interestingly, he also remembers dogs falling into crevasses – but points out that this early warning of unstable ground could be useful:

“You’d drive your dog team ahead of you, and if a snow bridge was going to give way, there was a very good chance it would give way under one of the dogs. That was an advantage we had over you people, because you had to fall down the bloody thing yourself!”

The remaining interviews will be made available on the BAS Club website as they become transcribed, and we look forward to hearing more recollections from Antarctic “old-timers”!

Christina