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Greeley: So they fly you down on a military

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cargo plane, so it’s not like your passenger jet with windows everywhere that you can kind of see where you’re coming into.

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You just kind of land, and they tell you you’ve arrived on Antarctica

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and pop open a door. Thank you.
Woman: No worries, see you.

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Greeley: It’s really breathtaking the first time you walk off the plane. You get a blast of cold air on

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the face, and it’s sunny. Everything is white, so it’s really bright

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and sunny. So we landed in McMurdo, which is on the coast, so you’ve got

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this huge volcano in the background, Mount Erebus, and

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the Transantarctic Mountains and Mount Discovery off to one side and sea ice

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and a little ice shelf that you just landed on. I think the thing that struck out

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to me the most is that you have these small little stations, and you can easily get in your head

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that you’re on campus or wherever, but sort of realizing that when you look out

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that it’s like, yeah the next place is a couple thousand miles of

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nothing. Just white, white snow. And it’s a long way from home.

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Brunt: It took us about twelve

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days to conduct the entire traverse. From South Pole back around to South Pole.

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And that’s moving roughly seven or so

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hours a day of travel. Then the real work begins.

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What we’re doing is collecting GPS data,

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which gives us not only our latitude and longitude, but it also gives us our elevation.

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We take those GPS elevation measurements, which are precise down to about

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the centimeter level, and we compare them directly against ICESat-2’s elevation

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measurements. We go to this part of

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the world because basically the ICESat-2 orbits all

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converge at 88-degrees North and 88-degrees South.

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So we get the densest data record. That’s great from a validation standpoint.

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Antarctica is a great place for this type of validation. It’s a

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relatively unchanging surface at that

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latitude and at that elevation. We’re interested in

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the centimeter-level accuracy of the satellite and centimeter-level accuracy of our GPS

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data. The reason why we’re interested in that is imagine a centimeter

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of water over the continental United States and now putting that into the ocean.

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That’s obviously a lot of water. Ultimately, when we’re interested in that level

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of change over that great distance. So centimeters become really

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really important.

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Greeley: It’s amazing how much elevation changes the environment.

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The air’s drier, it’s colder. The wind bites a little harder.

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Man: What are you doing, Kelly?
Brunt: Closing up the GPS.

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Trying to breathe.

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Simmons: Trying to breathe? What’s the problem with your breathing?

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Brunt: We’re at 10,000 feet above sea level.

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Getting higher every day it seems.

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Greeley: One of the additional instruments that we brought this year

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was this downward-looking laser to get a grip on surface

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roughness as we’re driving along. Sort of small-scale sastrugi

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and rolls in the snow as we’re driving along. And that gives us a handle of

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how much the GPS is moving around, if it’s floating on top of the snow,

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it’s moving with the roughness of the surface. And then ultimately

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make corrections for that if we need too.
Brunt: We’ve had two amazing traverses.

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The first one was fantastic and a bit pioneering and figured out what worked,

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what didn’t work. Second one improved on that. We’ve already thought about ways that we’re going to improve

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the next one for sure. Maybe streamline things, make things a little bit lighter.

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It’s only getting better and better.
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