We left the terminus today having succeeded with most of what we wanted to accomplish there. This morning we tested out the fluorometer, a device that ingests samples of water and tells you whether there is any dye in it before spitting it out again. The dye in this case is a glorified food coloring that we drop in by the teaspoon; it’s too diluted in the stream to see it, so the machine tells us whether its there or not. The idea is to put some in the stream on the glacier (that had the slush flow a few days earlier) before it disappears into a hole in the ice and see how long it takes to travel to outlet stream at the terminus where we are now. If it takes a short time, chances are there is a well developed conduit system beneath the glacier – basically a river. But if it takes a long time, chances the drainage system beneath the glacier is not very efficient, perhaps a network of cavities linked together by thin connections. It’s also quite possible that the drainage system will evolve over time, changing from an inefficient and slow system to something more like a subglacial river. The reason is that because the glacier spends 9 months or so with no water draining into it, any conduit system formed over the summer would get squeezed closed over the winter and it takes a few weeks of melting to form such a system again. We didn’t have the chance to do any actual experiments yet, but we consider it a good sign that the equipment is working as expected.
The weather today was also much nicer, and made for a pleasant trip back to our base camp. A disappointment for me was that the weather was not good enough for the high resolution repeat photography that I had planned. In 2003, I took a repeated a photo of the terminus taken by Austin Post in 1958, and this pair has been reproduced widely in many publications as it shows an impressive change in an arctic glacier that can only be caused by a change in climate. One of my major goals for this trip is to repeat that photo again, but this time using my new high resolution techniques. I also have several more photos of the terminus from other locations that I have yet to repeat. But it takes reasonably good weather for this, and we just didn’t have that yet. Fortunately there will be more opportunities for doing this later in the trip.
Turner: “OK, it’s a nice day, I’m ready to go! You grab the backpack.”
Turner: “I want fruit snacks!”
Jason’s makeshift staff gage can be seen directly across the stream. A timelapse camera is pointed at it, such that as the stream rises it will cover more pieces of tape on the pole and obscure them in the photos, allowing him to get a quantitative estimate of stream height from them. (Click on the panorama and drag to look around, press Shift to zoom in, Command (Mac) or Control (PC) to zoom out.) Enlarge this panorama
We extended a cable across the stream and will return to install a device which will measure the distance from the cable to the stream, as another means to measure stream height. (Click on the panorama and drag to look around, press Shift to zoom in, Command (Mac) or Control (PC) to zoom out.) Enlarge this panorama
A final goal of this excursion was simply as a shakedown for the backpacking we plan later in the trip. We sometime catch ourselves talking about this as camping, as if we not camping already. But it is qualitatively different in that in our base camp we have many luxuries that we don’t have while we are backpacking. For instance, we pre-cooked and froze most of our dinners at our base camp, so that all we have to do is heat them up in hot water. But this system is too heavy for backpacking. Similarly with clothes, pads to sleep on, etc – only so much fits in a backpack and we still need space for science gear, so it’s a challenge to decide what to bring and what to leave. We got most things right, but it was nice to have the opportunity to practice before getting too far from camp.
Jason and Joey enjoy a ride through the park.
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Friday, 20 June 2008 04:13
Day 59: Successful shakedown at the streamWritten by Matt Nolan
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