Now that the excitement of mass balance season has ended, we’ve been doing some miscellaneous projects and recovering from all the walking. I’ve spent a great deal of time getting intimate with some core dogs. These are 2 ‘teeth’ on the inside of the core barrel that grab the core and keep it from sliding out as you pull it out of the hole. An instruction manual for the Kovacs coring kit does not exist (that I am aware of), so in order to make adjustments to the way the corer works you either have to find someone who really knows how to use it, or spend an evening with the core barrel and a set of hex wrenches. I chose the latter.
I am starting to feel like I could successfully run a coring campaign. Luckily I am only interested in pulling 50 cm cores, so it isn’t particularly complicated. I managed 2 this week on Canada Glacier near the met station, and have been perfecting analysis techniques in camp. At this point I am only aiming for elementary core processing, so again, it isn’t particularly complicated. That said, it has taken a number of attempts with different equipment to get it right. A hacksaw has teeth that are too small and gum up with shavings, so you need a more dangerous looking saw; an MSR stove burns too hot and melts the sample too quickly, melting the sample on the stove in the hut subjects it to high air temps – a hotplate plugged in outside works perfectly. The goal is to melt the sample thin enough so that you are only looking through a single crystal (which you need cross-polarizers to see). I’ve started to get decent photos and hope to process the rest of the cores I already have this weekend. My goal is to measure grain size and bubble content only at this point and look for large differences within the upper 50 cm of ice, between glaciers, and over the course of the summer.
Besides this, we’ve installed Sensit (measures the quantity of windblown particles) at 2 met stations, changed the antifreeze out of a precipitation gage, photographed a cliff for terrestrial photogrammetry, and developed our design for conducting subsurface solar radiation measurements (this will be really cool if we get it to work).
I’ve seen the future, and it involves drilling a horizontal 10″ hole about 1 m deep in the side of a terrace on the glacier, about 10-50 cm below the flat top of the terrace. We can feed a pyranometer mounted on a met arm into the hole and measure how much solar radiation penetrates through the ice to the subsurface (both with and without snow on the surface). After we remove the pyranometer we can core down to its previous location. We will measure grain size and bubble content at various depths of the core. Then I can calibrate the model with direct measurements of grain size and subsurface radiation at the same location. If we can pull this off close to a met station, I will also have data on meteorological conditions and ice temperatures at the time. The coup de grace would be to pop into a cryoconite hole from the side and repeat the measurements from inside of an undisturbed cryoconite hole in situ. This plan sounds ambitious, but after dinking around this week, I don’t think it’s unreasonable.
If you’re still with me at this point, peruse some photos from the last few days – ice core drilling, Sensit install, cliff photography, ice core analysis.
