We saw a Polar Bear!
Does anything else really even need to be said about this blog? Just kidding, kind of. The morning after our first foray onto the ice we saw a polar bear lumbering along out on the pack ice as we were driving down the road along the beach.
I should mention that Ross went running on this same road the previous afternoon… after our polar bear guard advised him not to run north, and told him, “Don’t get eaten by a polar bear and don’t freeze your lungs.”
Hooray! As a group we have now had two really successful days of coring. Here is the map of our current sites again.
On Friday we cored at site #3 and on Saturday we cored at site #5, right off the coast of Point Barrow. Friday was possibly one of the coldest days here in Barrow with a wind chill of -55˚F, not at all uncommon for the area. The UIC science support group here just this year began advising scientists not to go out when it is that cold. But, after three days in a row of this weather, we were falling behind.
Needless to say, I froze – even under a thermal shirt, a flannel shirt, a fleece jacket, a micro-puffy, my giant Canada Goose jacket, snow pants, fleece pants, and thermal pants. I lost heat to my extremities pretty early on and after that there was no reviving myself.
On the other hand, this day was extremely exciting because it was the first day that we took the ICE-MITT box into the field! On our way home after our first day out, our ice core got bounced around too much in the sled and broke; now it is merely a test core. In an effort to prevent cores (or electronics) breaking while snowmobiling over rough pack ice we have begun using a longer, heavier sled and have outfitted it with an old futon cushion (which also served as a great couch and windbreak when we were out on the ice).
Our cores need to be unbroken in order for them to receive maximum benefit from the
ICE-MITT boxes. Because we are cooling the core from the two ends, trying to maintain the linear temperature gradient found in nature, we need great end-to-end thermal contact and great insulation around the core. A break in a core interrupts the thermal contact and acts as a mini insulator halfway down. I don’t know how many of you have ever cored ice, but to get a meter of unbroken ice is not the easiest thing. Ice (especially sea ice) is fragile stuff. Therefore, two broken ice cores into this site, we realized that it was hopeless, the cores kept breaking at the exact same place. This was because there was a gap layer in it.
After the initial sea ice had frozen, it broke up and pieces were tilted, flipped and rafted before more ice grew, leaving what were originally bottom layers (more porous and containing algae) upside down in the center of cores. It was clear that we were not going to get a full ice core from this spot. We packed up one of the broken ice cores anyway and sealed it into one of the slots in the ICE-MITT box as another test core.
Now, getting a core into the ICE-MITT box is a very precise procedure and has to be done as quickly as possible, because as soon as the core comes out of the ice into the super cold air it begins losing its in situ temperature gradient.
Once we get a core out of the ice, we remove it from the core barrel and measure it. The core has to be exactly 99.7 cm long to fit in the box and must have a nice flat surface on each end in order to achieve good thermal contact. So we saw down the core to the right length, using a jig that Chip, a really nice man from Thayer School Machine Shop, made for us.
Next we put the core in layflat, a long polyethylene bag that comes on a roll. Meanwhile, someone plugs the ICE-MITT into the generator and we carefully slide the ice in its layflat wrapper into its bed of silver insulation. Then we drill small holes in the core at the top, middle, and bottom where we then stick the thermistors (thermistors are what measures the temperature of the ice core).
We put pink, fiberglass insulation on top of the core and fill in all of the air spaces. We then cover it with a pink foam-board top and, over that, another layer of pink foam board. The ICE-MITT is programmed to record the temperatures that it reads from the thermistors when you first put the core in the box, and uses those temperatures as its set points to maintain.
However, we can also toggle these temperatures on the main screen as well. Great, now that you know the procedure, try doing it at -55˚F with heavy gloves on.
We moved our equipment a couple hundred yards away and had far more success finding unbroken, meter thick ice. We got one more core, packed it up and got the heck outta there since by this point I could no longer tell if I was frozen or boiling hot; apparently I wasn’t made for -55˚F. To our credit though, Friday was the first time ever that anyone has ever extracted a meter long sea ice core and maintained it at its in situ temperatures.
The next day we were at it again with our bear guard Mike.
This time the weather was only -22˚F and I dressed in the puffiest snow pants and jacket he could find, making me look not unlike a giant blueberry. This time we were driving mostly over land to get the coast right off of the point. We found some meter+ thick ice on a pancake in the middle of some pack ice. This time we were trying to get two cores, each a meter long, that would represent ice that was a meter and a half thick.
One core would contain the top meter of the ice, one core would contain the bottom meter of the ice and they would overlap in the middle. Some mathematical wizardry had to go into pulling this off, involving figuring out just how deep the ice was and how much ice to drill out of one hole in order to leave exactly a meter left before we would hit the bottom of the ice.
We drilled a 1.07 meter core from the top of the ice first, sawed it to length, packaged it and set it up in the ICE-MITT box. Next, we moved 36 cm from that hole, assuming the uniformity of the ice in such proximity, and drilled until the top of the core barrel was 55 cm above the ground, meaning that it had drill into 50 cm of ice.
Once we pulled out this piece of ice it would leave us exactly a meter left to drill before we hit water. And we were spot on; the ice core we drilled next was exactly the length of the box with no sawing needed!
We packaged it and sealed up the box and congratulated ourselves for the second day in a row for now being the first people ever before to core a 1+ meter of ice and maintain it at its in situ temperature. After we cored another multi piece core that was over a meter and ran the length of the ice and stored it in silver core tubes as back up cores. This was an even more successful day as everyone returned warm, but hungry.
Then to top it all off, the northern lights were on display that night! It was the first time I had ever seen them and I wish we could have gotten a picture of them swirling and dancing overhead; it was truly magical. And to really finish our day on our way home we saw three polar bears eating leftovers off of some whale bones from the Inupiat hunting season. Coolest day ever.