Posts Tagged ‘equipment’

Cruising Down the Ice Line

March 31, 2011

Original audio post.

Hi! It’s been an excellent and extremely productive couple of days. Yesterday the wind was much lower, so we went out to take cores from our various measurement sites. By the end of the day it was dead calm, and the subjective temperature had jumped by about forty degrees Fahrenheit. I don’t what the actual temperature was, but it felt like summer had suddenly arrived. We took 16 cores, dragged our chairs outside to have dinner in the sun, and went for a walk to enjoy the weather–hence the lack of blog post.

I feel like I talk about the weather a lot, but it really does have a huge effect on both our ability to do science and our general experience of this place. Without wind, there’s nothing to make noise except us and the ice. Last night we could hear the cracking beneath us very clearly. Actually, it doesn’t exactly go “crack”–it makes two different noises that Martin described today as “voomf” and “bloop.” I’m not sure quite what causes these different noises, but perhaps I’ll find out.

The calm also makes it easier to overheat in one’s cold-weather gear, especially when drilling ice cores, which is a labor-intensive job. I wrote a couple of limericks about the day’s activities.

Limerick One:
A day spent in the Allan Hills coring
Could never be useless or boring
The reward for our troubles
Is a bounty of bubbles
Tiny worlds we’ll spend hours exploring

Limerick two:
The Antarctic’s mercurial mood
Demands a relaxed attitude.
Though the morning’s harsh storm
Needs three coats to keep warm
By six, you’ll be more comfortable nude.

So. Today the weather was very similar to yesterday, light wind in the morning falling off to nothing in the afternoon. We retraced our footsteps from yesterday, taking albedo measurements at each site. Sunny weather isn’t ideal for that, but you can correct for the direction of the light, and we didn’t want to risk waiting for a cloudy, calm day that never came.

Snowmobiles and science equipment.

We managed to get all the measurements done by five, so now we’re hanging around camp waiting for dinner (we take turns being Cook for a Day) and sunning ourselves. Sunning yourself must be done with care in the Antarctic, of course, since the ozone hole is just above us, and the sun would be exceedingly bright even without it.

Ah, I forgot to mention–while Ruschle and I were making [albedo] measurements, Mel and Martin were making maps of the cracks in the ice, using the box-and-camera method I described the other day. [It's] now christened the Ice Fracture Observatory, or IFO. They randomized the location of their measurements by the again exceedingly scientific method of turning around three times, taking fives steps, then throwing a glove in the air and taking a picture wherever it landed.

Our randomization procedure.

I am excited to see what tomorrow will bring. We might hike over the hill and do reconaissance on the glacier on the other side. We might make measurements of snow microstructure. We might spend some time investigating the weird, inexplicable features we’ve take to calling “crevasse blisters.” For that matter, we might spend all day in sleeping bags again, hiding from the howling winds.

By the way, I’m not much for self-promotion, but I do think it’s really cool that, thanks to the wonders of modern satellite phone technology, I can give you day-by-day updates of what we’re doing. If you happen to know of anyone else who would also find it cool, I encourage you to tell them about it. Anyway, thanks for listening! ‘Till next time, as my Swiss-German-speaking colleagues would say, [word I cannot spell but which I am assured is the German version of 'ciao'.]

Great Scott!

March 30, 2011

Original audio post.

I mentioned Scott tents yesterday, and, since this morning dawned with 25-knot winds, I spent a lot of time contemplating the interior of mine today, cozied up in my sleeping bag. So, I thought I’d say a bit more about them.



Our three Scott tents.

Scott tents look rather like a child’s drawing of a tent at first glance. It’s nothing like the complex geometric curves of the tents you see marketed to backpackers nowadays; it’s a simple pyramid, four triangular sides sloping steeply to a pointy top. And most of them–most of the tents, that is–are bright canary yellow. I don’t know if the original version of the tent actually used by Scott was this color. It would seem terribly incongruous with the tragedy of their polar journey, Scott and his men dying slowly in a cheerfully sunshine-yellow tent.

Anyway. The setup process for a Scott tent is likewise simple, at least in theory. The edges of the pyramid are supported by four legs, which are joined together at the top. To put up the tent, simply stand it up and pull the legs away from each other until the walls are taut, then stake down the edges and guylines. This process becomes somewhat more complicated in windy conditions, as the rest of my team found out.

Once you’ve managed to stop the tent from blowing over, you can weight the edges with snow and put in the floor.

Now comes the tricky business of actually getting into the tent. The Scott tents are double-walled, which helps with insulation and prevents the kind of condensation-based indoor rainstorms we’ve been having in our kitchen tent. The entrance consists of two fabric tubes, one attached to the outside wall and one to the inside. The ends of the tubes can be cinched closed with drawstrings to keep the wind [and, just as importantly, drifting snow] out.

So, to get in, you first find the toggle for the outer drawstring, pull it out over the snow-encrusted string, wrestle the end of the tube open, crawl in, get the edge of the tube caught on your hat, trip over your boots, find the drawstring for the inner fabric tube, repeat the whole process, and finally fall into the tent with the outer tube caught on your boot and the inner one still lovingly wrapped around your shoulders.

Mel and Martin insist that this process is simplicity itself, and I am making a fuss about nothing. I think perhaps they have some weird arcane bond with their tents that I just don’t understand.

Mel, master of the Scott tent tube entry. Photo by Ruschle.

Don’t get me wrong–I do like the Scott tent. My tent is a snug home, and it contains my wonderful two-foot-thick down sleeping bag. Indeed, I think I’ll head there now. So, ’til tomorrow, ciao!

Ruschle happy in her down sleeping bag. These bags are so thick and fluffy that it is difficult to tell whether someone is actually sleeping in one until you peer into the face port. Picture by Mel.

You can string a clothesline inside the tent for drying your wet clothes--useful and decorative! Photo by Mel.

Complex Scientific Equipment

March 29, 2011

Original audio post. Thanks to Lori for the transcription!

Hey! Well, this morning’s weather was pretty unpleasant, although we weren’t sure why it seemed quite so bad. It goes to show how much your points of reference have changed when you find yourself saying “It’s only -15 Celsius with 10-knot winds. Why does it seem so cold?”

So, anyway, we stuck close to camp. Martin and I put together a very sophisticated scientific instrument, which might appear to the uninitiated to be a cardboard box with a hole cut in the bottom.

I transport the device to the field as Ruschle looks on. Photo by Martin.

This allowed us to take photographs of the cracks in the blue ice without the picture being washed out by bright sunlight. Upending the box box on the ice and taking pictures through the hole gave us images in deep translucent blue with a delicate tracery of dark cracks. We’ll use these pictures to try and quantify the effects of cracks on the amount of reflective light.

The cracks as seen under the box.

The weather improved in the afternoon, enough for us to go out and identify sites to measure. I don’t think I mentioned yesterday exactly what we’re looking for. As the ice flows, it moves into the region where wind can scour away the upper layers. So as you walk along the line of flow, you start in an area where the surface is still snow. Then you reach an area where the surface snow has been scoured away by the wind to expose dense old snow from years past (which, as you may recall, is called firn.) Walking further, you reach bubbly ice, and finally dense old blue ice. We are trying to measure along that same line of flow to get measurements from each type of snow and ice.

So, we marked the lines with the bamboo flags that are ubiquitous around McMurdo, and perhaps we’ll get to go back tomorrow and actually measure.

I’ve been concentrating a lot on the science we’re doing here because it’s pretty exciting. But I haven’t talked much about day to day life in camp. The Scott tents alone are worth a whole post, so I’ll try to talk more about that in coming days.

Oh, and we saw a skua!

A different skua, circling over Icestock hoping someone will drop their sandwich.

Skuas are the local scavenger birds. They look like a big brown seagull and like to dive-bomb people carrying food. This one was probably a bit lost. There’s not much to eat out here. But, it was the first living thing besides ourselves we’ve seen in days, so it was pretty interesting. Anyway, until tomorrow, cheers.

Repost: The Snow Device

February 8, 2011

Original post, called in on January 14, 2011. Transcription thanks to Jonathan Beall.

(Sorry it’s taking me so long to put these up, by the way. Believe it or not, adding photos is the most time-consuming part of the process. Maybe I need to work on my methods.)

“Well, the wind is blowing just about as hard today as it did yesterday, but a helpful meteorologist at McMurdo told us that things are only going to get worse over the weekend, so we figured we had better make the most of it. We headed out on snowmobiles into the ice field to choose a new place to take measurements. We can’t actually make albedo measurements when the wind is this strong because blowing snow interferes with them. But we can select good sites to measure, which saves us time later on. Once we get a calm enough day, we’ll jump on our snow machines and spend it running around to different sites with our albedo measuring device. (I made a post about this instrument, the ASD, some time last year. If I had internet access, I’d link to it, but since I don’t perhaps some helpful person will do so in the comments. [A couple mentions, but I don't see a post all about it.--Jonathan] [He's right, I misremembered. Sorry! I'll have to make one. -- me]) We marked a site and took an ice core or three, and then went home for lunch.

In the afternoon, we tested out Martin’s device for measuring snow surface areas, which he made himself. It’s a sort of framework meant to be inserted into the snow. Then you dig the snow out of it to make a pit and take a picture of the wall of the pit using near-infrared light.


Ruschle, Mel and Martin working on the pit.

Snow grains of different sizes reflect different amounts of near-infrared light. They reflect different amounts of other light too, but the differences are easier to see in the near infrared. It’s a little bit of a simplification to say that the amount of reflected light tells you the grain size. It really tells you the surface area, because it tells you how many surfaces the light has bounced off before it reaches the camera. Once you’ve taken that picture, you dig a second one, leaving just a thin wall of snow, and shine a light through that wall to see how much gets through. This lets you calculate the density of the snow.

Snow structures.

It also happens to be beautiful. The different layers in the snow make delicate strips, shading from light to dark, depending on the time of year they were deposited, the weather when the snow fell, and various other things.

So, that’s what we were trying to do. However, things didn’t go quite as planned. We soon discovered that the snow here is much harder than the snow in the Alps, and we couldn’t insert the frame without damaging the snow we wanted to measure. Finally, we figured out that we could drill holes in the snow with our auger, which allowed us to set up the device with relative ease, although it still took a lot of hard shoveling to dig out the pit. And then, at some point, as we tried to get everything set up, we made the unwelcome discovery that Martin’s supplier for frame connectors had been somewhat mistaken about their tolerance for cold, and the frame snapped in half.

A broken fitting.

And of course, remember, that we’re doing all this in twenty-knot winds. But we finally managed to get everything set up, we took our measurements, and we went home feeling like scientific heroes. We got to take an item off the list of tasks that Ruschle wrote up for us, so we’re all feeling pretty good about ourselves.



The wind meant that we had to put a tarp over the site to prevent everything from being covered with fine drifted snow.


It’s supposed to snow tonight. It should be an interesting weekend. Until then, ciao.”


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