This week at Mawson: 23 August 2013

Sea ice measurements

Since the beginning of April we have seen the sea turn to ice. As part of a scientific program the thickness of the ice is measured each week when the ice is thick enough to travel on safely. Four spots are drilled each year at Mawson and these include West Bay, East Bay, Kista Straight and Horseshoe Harbour. The exact positions are found by using a GPS and then a cane pole was placed in the hole as a marker.

This week I got to go out with our Field Training Officer (FTO) to take the measurements.  There are three measurements we record which are the thickness of the ice, the thickness of the snow on top of the ice and the distance from the top of the ice to the water which comes up the drilled hole. When first drilled the ice was approximately 400mm thick and when we did it last the average thickness was 1300mm. West Bay was the thickest at 1390mm and Kista Straight was 1210mm. Some results from the last couple of months are in the table below.

This time of year when the ice is approaching its thickest going on previous records. Kista Straight is normally below the other as there is a strong current running through the water. Also if there is a large amount of snow on the ice it acts like an insulator and stops the ice from growing thicker. I find it very interesting how nature works and also don’t mind the advantage to get off station for an hour or so.

With a smile, Trent

Previously, in The Wall Part I, we were up to the point where we were almost ready to start fixing the fibreglass panels to the steel framework. The only thing left to do was to plumb and straighten up the structure then fix in some permanent bracing and tighten up all of the nuts. The framework was now complete.

The first row of wall panels was fairly simple as they were flat sheets and sat pretty much straight on the floor. All of the panels varied slightly in size and shape so they had to be clamped into place on the framework and fixed in situ with bolts after drilling through the steel framework. A nominal gap of 3mm was left around the panels to allow for the size differences. The next two rows of panels were fixed off a couple of ladders. These went on reasonably easy as they only had small contours in them to simulate a real rock face. The contours were quite often concave and ended up being directly over the steel framing which meant the panels had to be packed out behind the bolt fixing point so a wide range of different bolt lengths had to be used. Once the panels were too high to reach from a ladder we fixed the remaining four rows out of the man cage on the forklift, one person in the man cage drilling the fixing holes and another behind the wall tightening the nuts on the bolts. The operation went pretty smoothly once we had our method worked out and the panels were finally finished.

After fixing the panels it was time to fit the anchor points to the roof framing so that the pulleys for the belay lines could be attached. One was simple, as it was just a matter wrapping a chain around the trussed rafter that was directly over the wall and attaching the pulley. The other point had to be fabricated out of steel and fixed to the roof purlins. That was the last task that required the use of the forklift and man cage. The only thing left to do was to drill the floor slab and grout in two ferrules to which the belayer and the belay lines are attached while somebody is climbing, a simple job by comparison to the rest of the project. Hand and foot holds were fitted and that’s it, the climbing wall is done!

Pete Layt, Pete Cubit and myself (Rowdy) headed off to Auster rookery on Saturday morning. We were hoping the weather would stay good and we’d get to see emperor penguin chicks. This is the time of year when they’d be hatching and we wanted to get pictures when they were still very young.

Lucky for us, we weren’t disappointed. Wow, wow, wow is about all I can think of to say about the time spent out there. Soon, as we pulled up in the Hagg, they came and checked us out. They are so elegant, regal, inquisitive and clumsy all at the same time. I could have sat there for hours being entertained by them. But we had come to see the chicks.

It was hard to tear ourselves away from our welcoming committee to get closer to the rookery. Then there they were, and nearly everywhere we looked there were chicks. Thank goodness for the zoom lens, otherwise they’d be almost impossible to see. There’s this gorgeous tiny black and white head peeking out from under a special fold of abdominal skin, which covers the chick to help keep it warm. I had to head back to the Hagg a few times to warm up my hands. It was getting so cold that even though I had power in the battery my camera just didn’t want to work.

So while we still had a bit of light we headed off to spend the night at Macey Hut. The weather for Sunday was looking good and we were planning to spend a few hours back at the rookery before heading back to station. Macey is about 10 kms away so it didn’t take to long to get there. Once we and the hut had warmed up a bit we settled in for a nice cosy evening with a nice red and lamb stew and rice. Most of the conversation that night was about how amazing our day had been.

The next morning was a repeat of Saturday. It didn’t take us long to have brekky, pack up and head back to the rookery. That, too, was a repeat of the previous day, absolutely awesome.

I can’t wait to get back in a couple of weeks to see how much more they’ve developed. We’ll make sure to keep you updated.

This week we tour the Cosmic Ray Physics department, or “Cosray”. The study of cosmic rays from space commenced at Mawson in 1955 and has been almost continuous since then, with the exception of a short break in 1978, when fire damaged equipment in the building.

The monitoring and data collection of cosmic rays (and a few other sciences) was mostly automated at Mawson in 2008/9, mainly through the additional expansion of station networking and replacement of data acquisition systems. Although no specific science personnel are employed at Cosray during winter anymore, the observatory equipment is now managed by the Bureau of Meteorology, with additional assistance from communications, electrical and most other trades as well.

The current Cosray building and vault system was constructed back in 1971 and it’s exterior is unfortunately now looking a bit worse for wear. As can be seen by the large number of heavy gauge guy wires — the building is very exposed to the katabatic winds because of it’s location at the very top of the station — virtually the highest point on Mawson’s rock.

Inside, the building houses an array of cosmic ray Muon telescopes and Neutron Monitors — large multiple horizontal tubes with detectors within. Both count the numbers of cosmic rays from space — but the Muon telescopes are also able to provide an indication of where these particles come from.

So what is a cosmic ray?

Simply put, cosmic rays are “pieces of atoms” (mainly protons and atomic nuclei), flying through space at nearly the speed of light. Because these particles have mass, as well as high speed — they can carry enormous levels of energy. Trying to harness that energy has, so far, been impossible.

These high speed cosmic particles are charged, so they interact with the earth’s magnetic field, or any other magnetic field in space (i.e. from other stars and planets). This changes their direction so that once they eventually reach our telescopes it’s often difficult to tell exactly where they originated. Current theory suggests that most cosmic rays are produced from supernova (or exploding stars) but there has been some conjecture on this.

When first discovered, it was thought that all cosmic rays probably originate from our sun. But that was disproved early on, because the rate of cosmic rays detected at a certain point on earth is basically the same at night, than it is during the day. Or in our case in Antarctica, the amount of cosmic rays detected here is reasonably constant all year round! There are sometimes variations from year to year.

Some other interesting things about Cosmic rays:

• Some physical theories suggest that cosmic rays shouldn’t really exist at all!
• Over 2 million cosmic rays fly through your body every day. It’s hard to avoid them,
• We cannot possibly create a cosmic ray on earth!
• Cosmic ray science still has many unanswered questions and challenges ahead.

You can check out our Mawson cosray data.