Posted by: sioglac | Nov 28, 2011

The Field Plan

So now that you have some idea of why we’re going to the Whillans Ice Stream, maybe it’s about time I tell you more specifically what we’re doing while we’re there. Conveniently, we had a meeting to discuss the field plan, so this is more or less a summary of that meeting. I’ll start things out by showing you Huw’s AAA-style map, complete with travel distance matrix:

As I’d previously said, we have 3 LC-130 flights to get us and our gear into the deep-field, landing at the blue dot labeled “GZONE.” I’m totally stealing this from Paul, but just think about this for a moment: the New York Air National Guard is so good at their job that they will load about 15,000 pounds of cargo into a gigantic plane and land it in the middle of an ice sheet with no runway and really no backup plan (other, of course, than safely turning around and heading back to McMurdo). Just a plane on ice. Specifically so the eight of us can do our science. So cool (and astonishing). Anyway, three flights! The first flight will be only cargo– things like snowmobiles, tents, food, etc. The second flight will be more science-y cargo plus the eight of us. The last flight will be whatever is left of our cargo and some of Paul’s cargo.

Last year’s field team “wintered over” some gear (i.e. left some stuff on the ice that was too inconvenient to ship back) near Subglacial Lake Whillans (SLW) and Camp 20, so the first goal is to retrieve that. We will split into two teams: Knut, Atsu, Ben, and Rory will stay near the grounding zone, establish our main camp there, and shuttle our wintered gear from Camp 20 to our camp. Just FYI: Camp 20 is on the McMurdo-South Pole Highway (AKA the South Pole Traverse route), which is driven 1-2 times a year to send fuel and heavy equipment to South Pole Station to allow it to function year-round.

Meanwhile, Huw, Lucas, and both Matts (it’d be too easy if we split up, right?) will drive (on snowmobiles) the 70 or so miles up to Subglacial Lake Whillans, where we will set up a camp there for about a week. Lucas and I will service the nearby GPS units (meaning we retrieve the data, make sure the antenna are high enough to remain above the next year of snowfall, check the batteries/solar panels/wind turbines, update the firmware, and generally make sure everything is working correctly). As I said earlier, we learned a whole lot from last year’s data and we will be tweaking the location of some of the GPS units in light of our new insights, so that will be part of the servicing as well. While we do that, Huw and Kiwi Matt will be recovering the hot water drill that was left near SLW, which is critical for drilling holes for seismic shots. In case you are new here, active seismics is one way we will examine what the ice looks like beneath the surface and consists of us creating seismic waves in the ice and listening to how they travel through the ice. You can read up more about some various glaciological methods here.

After our work at SLW is done, we will traverse to Paul’s camp (blue dot I181). Lucas and I will again service the nearby GPS units (if you didn’t figure it out yet, Lucas and I will be doing a lot of snowmobiling), while Huw and Kiwi Matt will help Paul and his team of three drill shot holes with the hot water drill for their active seismic work. When our work there is done, we will reconvene with the rest of the crew at the grounding zone. In the time we were away, they will have set up camp, built all the necessary field gear (like, I kid you not, a wooden conestoga wagon), and started to drive a dense grid of ice-penetrating radar surveys across the grounding zone. Atsu will also start his extensive gravity surveying. I know I’m being a bit vague as to what each of these geophysical methods will tell us about how the ice behaves; hopefully that will come in time.

Once we are all back together, we have about 4-5 weeks worth of seismic work to do. Because that only requires 2-4 people at a time, there will be time for ancillary experiments at the grounding zone. For example, we will set up small, temporary grids of GPS units across the grounding zone to measure how the ice deforms across the grounding zone over one tidal cycle. Lucas will return to spots where the ice speed has been measured in the past to continue monitoring how the Whillans Ice Stream has slowed down over the past decades. Because we will have radar systems and available GPS units, we are also planning to drive the ground tracks of a satellite that was launched last year (Cryosat-2), in an effort to validate the satellite’s measurements of ice surface elevation. We have been doing a similar (and successful) experiment with a different satellite (ICESat), which we will also continue this field season.

At some point during the season, Lucas and I will fly to the furthest GPS sites (near Subglacial Lake Mercer, which is the lake with the red dot labeled LA09) via twin-otter airplane. Depending on how the pilots fuel needs, this might include a one-night (or multi-night!) stay at Siple Dome. The season will conclude with the LC-130 picking us and our cargo up in early- to mid-January, effectively wrapping up the surface geophysics part of the WISSARD project.

So that’s the plan. Here’s some good news: we got a passenger notice saying our flight is scheduled for Thursday, December 1. The bad news, though, is Sridhar got that same notice over a week ago and just left for WAIS Divide (on his way to Pine Island Glacier later in the season) this afternoon. Hopefully we won’t be waiting that long!

-matt

Advertisements

Responses

  1. So now I finally understand it all. Eloquently explained, Matt! Fingers crossed for a Thursday departure. At least now you have time to make all those nitty-gritty poster changes 🙂

    • If it wasn’t obvious to you already, I wrote this blogpost specifically to procrastinate poster edits.

  2. […] what day-to-day work was like last year and this was what we did for more than half the season. I talked a little about our active seismic work, but as my 9th grade English teacher taught me, why tell […]


Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

Categories

%d bloggers like this: