Archive for August, 2009

Practice Makes Perfect

August 31, 2009

We went out onto the sea ice on Thursday for our safety training. It was the first time I’ve been very far out of the sheltering hills that surround McMurdo, and it demonstrated just how much I have to learn about staying warm in Antarctic conditions. Wearing two layers of thermal pants, two layers of thermal shirts, wind pants, two pairs of gloves (with a set of chemical handwarmers), and my “Big Red” Antarctic parka, I still got cold. In particular, it took just a few minutes to stop being able to feel my fingers; I had to borrow a pair of mittens to get them working again. I’m not sure what the temperature was, exactly, but the wind was well upwards of twenty miles an hour.

The lesson in sea ice safety was quite interesting, though. The basic goal of sea ice safety is, of course, to avoid falling through the sea ice into the 28F/-2C seawater below. Thus the procedure is more or less as follows (DISCLAIMER: I am not a professional sea ice safety trainer. Should you find yourself with occasion to drive over sea ice, please consult someone who knows what they’re doing, first!)

1. Look for cracks in the surface. These can be quite thin, or mostly covered with snow, but it’s usually possible to spot them if you stay alert.

2. Shovel the snow off of the sea ice in a channel extending a couple of feet from the crack. Note that there are several levels of sea ice in this particular crack. This happens because the sea ice that formed when the crack opened and re-froze hasn’t had a chance to get as thick as the older sea ice.

3. Drill some holes to check the ice thickness. The standard drill bit used for this is one meter long, so it doubles as a convenient measuring stick.

4. The ice must be at least 30″ thick to be considered safe. The edges of this crack are too far apart to drive over, and the central ice is too thin to drive on, so in this case we’ll have to find another place to cross.

If the crack is narrow enough, however–less than 1/3 of your tread length–then you can just drive over it.

(That’s my artistic rendering of a Pisten Bully.) As of Saturday morning, I know how to drive one. WHEE!)

Observation Hill

August 29, 2009

Currently working on a post about Sea Ice Safety–for some reason I decided to whip up some diagrams, so it’s taking a bit longer than expected. In the meantime, here are some pictures from Thursday afternoon when my advisor and I hiked up Observation Hill.

Observation Hill as it appears from the middle of McMurdo.



In the foreground, the cross commemorating Scott and his men; in the background, my advisor and also the Sun.

It was particularly exciting to see the Sun because, from most of McMurdo, it hasn't yet been visible.

It is certainly a privilege to be here during one of those brief times when the sun actually rises and sets every day.

Salt, Sea Ice and Science

August 27, 2009

Science-wise, our team has been busy getting settled in to the lab and taking all the trainings required for us to be allowed to do things. We won’t be able to get out on the ice until after our Sea Ice Training on Friday, so I thought I’d take this opportunity to talk a little about the actual science we’ll be doing.

You may recall from earlier posts how increased albedo can lead to a Snowball and CO2 can end one. As the planet cooled off and the climate system change, new types of ice could form that are rarely, if ever, found on our modern Earth. That’s why we’re down here in Antarctica in the winter–to find modern analogs of this very, very cold ice.

During our first couple of weeks here we’ll be looking for cold sea ice. “Sea ice” in science terms means ice that forms when seawater freezes–ice that formed from fresh water just happens to be floating on the sea, like icebergs, doesn’t count. When sea water begins to freeze, it forms a large number of small crystals of ice, called frazil. This stage is also called “grease ice” because it looks a bit like an oil slick on the water. Eventually the crystals begin freezing together into a solid sheet. As they freeze they trap small pockets of salt water, and these are what we’re really interested in.

As you may know, salt lowers the melting point of ice so that it becomes liquid at lower temperatures, a property that is useful when melting ice off of driveways or making ice cream by hand. Sea water averages about 3.5% salt (that’s six or seven teaspoons in a quart of salt for you American types, or 35g in a liter for the rest.) This particular salinity level means it freezes at 28F or -2C. As it freezes, the ice pushes out the salt, and the water in the pockets of salt water–the brine pores–gets saltier. If the ice gets colder, this saltier water will also start to freeze, pushing out more salt and making the brine pockets smaller and saltier still.

At -9F/-23C, some of the salt in the water starts to form crystals, called hydrohalite. Like the many small crystals in snow or table salt, these crystals of hydrohalite are good at scattering light. By sending light back out the way it came, the crystals in the brine pockets can increase the amount of light reflected from the sea ice. Our colleague Bonnie Light demonstrated this effect in the lab, and we are hoping to find it out in the field. These albedo measurements will help improve models of Snowball Earth. Because so much area in the sunlit tropics is covered in sea ice on Snowball Earth, small changes in albedo can have large effects, so it’s helpful to have measurements that are as accurate as possible.

Not all of our equipment is here or unpacked yet, but I’ll post photos when it is.

Home, Icy Home

August 25, 2009

So, I arrived in McMurdo on schedule on Monday, but I had some trouble getting my laptop onto the ‘Net. Here’s a post I wrote on the plane coming down, and here are some pictures from the journey and of the station itself.

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Currently on the plane to McMurdo, just about at the midpoint between there and Christchurch. It is a very loud plane; everyone is wearing earplugs, so there’s not a great deal of conversation with one’s seatmates. So I thought I’d take this opportunity to tell you about the International Antarctic Centre and the “Antarctic Attraction” museum. (Incidentally, Antarctic Attraction would be a great name for a romance novel. A parka ripper, if you will.)

Christchurch evidently takes great pride in its status as “gateway to the Antarctic”. The tourist information center downtown even includes a small “Antarctic shop.” The actual International Antarctic Centre is out by the airport, and acts as a base for the New Zealand, U.S. and Italian Antarctic programs. I don’t know much about the Italian Antarctic program, but the Kiwi and American programs are quite neighborly, with New Zealand’s Scott Base being located just a couple of miles from McMurdo. (Our team actually has an invitation to dinner there tomorrow night.) According to my Lonely Planet Antartica guidebook, both bases sit on land to which New Zealand has laid claim. The status of Antarctic territorial claims and the Antarctic treaty are pretty fascinating topics in and of themselves, which I’ll address in another post.

The CDC (Clothing Distribution Centre) where they issued our gear is in the International Antarctic Centre right across from the Antarctic Attraction, so my advisor and I decided to go investigate and see how much they’d gotten right. (Most of it, as it turned out.)

The Little Blue penguins are indifferent to their admirers.

We got there just as they were feeding the Little Blue penguins. Twenty or so birds–rescued from predators, car accidents, or parental abandonment–make up the museum’s Little Blue penguin colony. It is worthwhile to note that while Little Blue penguins are widespread on the New Zealand coast, they are found nowhere in the Antarctic. Evidently the Antarctic Attraction felt that any penguins were better than no penguins at all.

Feeding a recalcitrant penguin. Since they are all rescues, they tend to be invalids to a greater or lesser degree. A few have missing or paralyzed flippers and therefore a tendency to swim in circles.

The Antarctic Attraction also features a simulated Antarctic storm, taking place inside a refrigerated Antarctic landscape held at around -5 C/20 F. The windchill gets down to about -25C/-20F during the storm, which is respectably nippy but distinctly unimpressive to Alaskan sensibilities. I found the ice slide much more entertaining.

Museum visitors relax after their harrowing artificial ordeal.

Once upon a time, clipart dinosaurs roamed the Antarctic.

Everybody loves penguins! Remember, penguins in the Antarctic, polar bears in the Arctic. It is interesting to ponder whether, if introduced to the opposite pole, either species would thrive.

More bits of exhibit.

Gear, Revisited

August 23, 2009

Examples of things you may find in your allotment of gear. Exactly what you get depends on your job.

Examples of things you may find in your allotment of gear. Exactly what you get depends on your job.


Went out to collect my Extreme Cold Weather Gear from the stores today. There were a few dozen other folks there, maybe a dozen or so other first-timers. I milled around, being slightly nervous and taking photos of things.

They gave us a Briefing and had us watch an Instructional DVD, which mostly just went over what to pack in which bags. Your parka, windpants and boots go in your carry-on, and you put them on before the flight, just in case. Then you’ve got your checked bags, like with any airline, including a “Boomerang Bag.” You pack your toiletries and spare clothes in the Boomerang Bag, and if the flight gets delayed, or has to turn back halfway to the Ice, they give it back so you have something to get you through the 24 hours until the next try.

After the briefing we got to test the fit of everything we’d been issued. Here I am kitted out with full-on ECW (Extreme Cold Weather) gear:

Ready for anything.

Ready for anything.

And minus the parka:

Antarctic ninja.

Antarctic ninja, while feared and respected for their skills in cold-weather combat, are usually easy to spot on the ice.

The flight is at 0700 tomorrow, because it takes five hours to get to McMurdo (it’s a faster plane than they usually use) and they want to get there during the brief hour or two of daylight available this time of year. This means we have to check in at 0400 and, consequently, leave the hotel at 0315.

So I had best get started sorting my things into Carryon, Boomerang and Checked. With any luck I’ll have time tomorrow on the plane to compose a post about the Little Blue Penguins and artificial Antarctic windstorms at the International Antarctic Centre museum.

Escaping the Snowball

August 22, 2009

So, how does a planet get itself out of a Snowball state? The short answer, as I mentioned in my last post, is “carbon dioxide.” When the Earth was frozen over, volcanic activity didn’t stop–volcanos kept pumping gases, including greenhouse gases such as CO2, into the atmosphere.

Now we get into the geochemical aspects, which are a bit outside my field, so please take my explanation with a grain of salt. Normally, CO2 that enters the atmosphere reacts with rocks on the Earth’s surface, creating carbonate minerals. This process gradually removes CO2 from the atmosphere. When the amount of CO2 in the atmosphere increases, the Earth warms, which speeds up the weathering process and removes CO2 more quickly. This CO2 feedback helps keep the Earth at a comparatively stable temperature over the long term (CO2 weathering is slow, so it can take thousands of years for CO2 to leave the atmosphere even at warmer temperatures.) Here’s a paper on the CO2 weathering feedback (link goes to PDF file) for those who are interested in a more in-depth treatment.

Much of this CO2 weathering process occurs when CO2 combines with minerals to form carbonates, such as calcium carbonate (the principal component of limestone, among other things.) This process is helped along when CO2 mixes with water in rain, rivers, and the ocean. However, on a Snowball Earth, little rain or snow would fall, and few, if any, rivers would flow. No CO2 could dissolve into the oceans, because they would be cut off from the atmosphere by a thick layer of ice. Instead of weathering out of the atmosphere, the CO2 would simply build up over time. As carbon dioxide levels increased, so would the greenhouse effect. Eventually, the CO2 would reach such high concentrations–hundreds of times modern levels, by some estimates (for example, Hoffman and others, 1998)–that the warming greenhouse effect would overcome the cooling effect of the light-reflecting ice.

When the greenhouse finally overcame the ice, it melted quickly, suddenly transforming most of the world’s surface from brilliantly reflective ice to dark, absorbent sea. Without the reflective effect of the ice, the greenhouse effect took over and the temperatures soared. At the same time, the massive amount of CO2 in the atmosphere began to dissolve into the ocean, where it precipitated out to form thick layers of carbonates. These “cap carbonates” are still visible today and form one piece of evidence for the Snowball Earth theory.

This is, of course, just one of several ideas about how the Snowball Earth scenario might have played out. It’s possible that, instead of Snowball Earth, there was a “Slushball” Earth, with open water at the equator. A Slushball Earth would have much less trouble supporting life, which would thrive in the areas of open ocean. On the other hand, that open ocean would act as a sink for CO2, and the Slushball might not be able to accumulate enough CO2 to overcome the albedo of the ice on the rest of the globe. Snowball Earth researchers continue to search for a model that will balance these various factors–account for sea-level glaciers at the tropics, provide a refuge for life, and permit enough CO2 buildup to initiate the return to a normal climate.

But you don’t have to take my word for it, as Levar Burton would say. Much more information on all these topics is available at SnowballEarth.org, which gives a good comprehensive overview of the whole business.

<A diagram from SnowballEarth.org, which gives a good graphical overview of the Snowball event.

A diagram from SnowballEarth.org, which gives a good graphical overview of the Snowball event.

Back On the Job

August 22, 2009

Have returned to Christchurch, after a rapid tour of the South Island and Wellington. From here on out I’m going to try and post every day that I have Internet access, starting tomorrow when they issue me my Extreme Cold Weather Gear. Exciting times.

Waypoint

August 16, 2009

Have completed the first leg of my journey, and am awaiting my 14-hour flight to Sydney and subsequent transfer to Christchurch. I’ve got five days to enjoy New Zealand before I get back into Antarctic preparations, so I may not post much here. I’ll try to get to the Christchurch Antarctic museum thingumbob, though, and put up some pictures.

Gear

August 15, 2009

Keep meaning to post more about Science, but I have been nitpicking myself on accuracy. I believe I shall try to do more citing in my explanatory sorts of posts.

In the meantime, my snazzy prescription glacier glasses have arrived to save me from snow blindness:
Sunglasses are Cool, regardless of whether you are in Antarctica or not.

I also have backup eye protection in the form of these snow goggles, which were the only pair I could find that would fit over my ordinary glasses and which have a tiny fan on them to prevent fogging. I did not realize until I took this picture that they are, basically, larger than my entire head.

Goggles, or facehugger?

Life's little niceties

August 8, 2009

T minus one week. This is beginning to seem more real.

On the suggestion of someone I met at my advisor’s Fourth of July party, I am reading The Worst Journey in the World, Apsley Cherry-Gerard’s account of Scott’s ill-fated expedition. Reading it has convinced me that I will be living in the very lap of luxury during my trip. The food will be plentiful and varied. I will be unlikely to develop scurvy. When I’m camping in the Dry Valleys, my gear will be constructed of the best synthetic, high-tech fabrics, and my tent will be sturdy and warm. I will not have to get it there by personally dragging it the entire way on a sledge. And when I’m at McMurdo, I will be able to take a hot shower. Every day. All that and Internet access besides. Yes, the modern Antarctic explorer has got it pretty easy.

The past couple of weeks have been an ever-accelerating rush to acquire appropriate equipment, mostly scientific but some for personal use. All visitors to the Antarctic, for instance, are required to bring two pairs of sunglasses. With the reflection of sun off snow and ice, and the extra UV allowed in by the hole in the ozone, snow blindness is a very real concern. It turns out that prescription glasses for someone with terrible eyesight, which I have, in a wraparound “glacier glasses” style, which is necessary for snow use, cost a fair bit. Fortunately the grant will cover it. A store in Fremont supplied my second set of sunshades, a pair of snow goggles designed to fit over my current glasses and fitted with a tiny fan to help prevent fogging. (The odds that it will continue working in Antarctic winter conditions are probably slim, but it was the only pair they had–and, hey, gadgets!)

In addition to the eye protection, I have been acquiring some small-scale cold-weather gear. Several people have instructed me that I should be sure to bring my own hat–it is not quite clear to me whether the one supplied to you by the logistics folks fits poorly or is simply unbearably unstylish. Socks, because it’s nice to have your own, and gloves, because the odds that they will have any small enough for my hands are rather low. Perhaps a balaclava. Next problem: what books have a sufficiently high quality-to-weight ratio to be worth bringing?

I know I promised to explain how Earth escaped from Snowball conditions. Short answer: carbon dioxide. Long answer will arrive soon.


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