August 17, 2020

Postcards from a (formerly) frozen icebreaker: Part 55

Posted by larryohanlon

By Matthew Shupe

8/4/20 Searching
With still some days until the Akademik Tryoshnikov gets here, we’ve been trying to use our extra time with Polarstern wisely. We’re going around to recover various assets that were installed on the ice and have not spread out all over the place. Yesterday we were off to recover some buoys that were close to the Central Observatory during the last leg, then today we returned back to the L2 area. The floe was still about 500m across the other day when we recovered our flux sled, and we’ve had the notion to get back on the ice for one last hurrah. We want just a few last physical measurements, and these would be a great bookend for the L2 site, complementing the physical samples made back in October during the initial installation. But alas this was not to happen. Instead, as with our main floe some days ago, L2 has also disintegrated into a 1000 pieces. We had left a couple buoys there but now they were all separated.

First we found a SIMB3 buoy bobbing amid little ice floes. Easy to just pluck this one up out of the water. Then the ocean flux buoy; this was much harder as it was still embedded in a small chunk of ice. The ship’s crew pumped ocean water on it to melt out around the base and then lifted it up and out of the water, followed by a tether below and additional instrument packages. I’m glad we recovered this system as we believe the next crew of scientists will be able to redeploy it during leg 5 to help get ocean heat flux measurements at this crucial time of year when the ice melt slows and eventually stops, giving way to another freeze up. On this day we did not get the ice tethered ocean profiling buoy, as it was nowhere to be found, but we have to call this a highly successful day nonetheless. Setting up Leg 5 to hit the ground running.

The ship’s crane lifts instruments from the floe. Photo: Lianna Nixon/CIRES and CU Boulder

8/6/20 A Bear Morning
Our days lately have been strange. Searching around the ice in dense fog. It’s so hard to see anything, and especially some of these small buoys we’ve been hunting. But today was a beautiful day. Bluebird conditions again. And it started out with a great bear. Right off the rear of the ship, no need to chase it off because we are in transit anyway with no work on the ice. Parked temporarily here waiting for more coordinates. The bear came right up to the side of the vessel, sniffing the air. He hopped from little ice chunk to little ice chunk, scoping out the whole ship. Then wandered off, apparently we are not interesting enough to take more than 15 minutes of his attention.

A polar bear photographed earlier in the expedition. Photo: Esther Horvath/Alfred Wegener Institute

Then our day took us on to the L1 site, and more recovery. Successful again, although this time we did pull up the ice-tethered ocean profiler, all 800m worth of cable! That took many hours and a lot of work, in part because it was still frozen into a small chunk of very thick ice. Here the ocean is not so deep. We are on the Greenlandic shelf at only about 200-250m deep. So clearly there is not enough depth here to support the full length of the cable. When we finally recovered the instrument package at the end of these 800m, it had clearly been dragged through the mud on the seafloor.

The Ocean Team recovers an instrument. Photo: Lianna Nixon/CIRES and CU Boulder

There was another interesting moment today, seeing the remains of our flux sled from L1. Some months ago it had been eaten by a ridge; just totally destroyed. Chris and others had cleaned up the wreckage as best they could, recovering many instruments, some of which were damaged beyond repair. As the ship crept into position today to recover another instrument, I saw a pipe sticking up from a ridge. Then a few more details that looked familiar: a couple of cables, and straps, a grounding wire. Then, with the right angle, I could see down into the water and there, protruding from the bottom of this ridged floe, was the bottom of our sled. Metal pipes sticking out and clearly mangled. This shows the strength of the ice, able to simply crush our 1000-lb sled like a tin can.

Read more of Shupe’s posts here

Scientist Matthew Shupe (CIRES/University of Colorado Boulder) is blogging from an icebreaker frozen into Arctic Ocean sea ice, so far north that the Northern Lights are no longer visible. Shupe is co-coordinator of the international Arctic climate mission MOSAiC, or Multidisciplinary Drifting Observatory for the Study of Arctic Climate. Today, he’s among about 100 people aboard the German icebreaker Polarstern. Shupe, who also works for the NOAA Physical Sciences Division in Boulder, Colorado, began planning the mission more than a decade ago, with an expanding network of scientific leaders from around the world. In a series of short posts from the ship, he shares his experience of the expedition, led by the Alfred Wegener Institute. U.S. funding for MOSAiC sciences comes primarily from the National Science Foundation and the Department of Energy. Follow the expedition: and @MOSAiCArctic.