We have just crossed southward of the 80 degrees North line. We are still well north of the Arctic Circle, of course, but our research permit for sampling ends at this latitude, so we will occupy no more stations. The multibeam sonar will keep pinging away as usual while we pick our path southward, adding bits of data to the very limited sea-floor map information in the region – all ships with mapping capabilities try to do this as a service, over time building up a sea floor map that is useful for navigation as well as scientific investigation.
We got out of the Petermann Fjord region a day early because the ice was packing in and at 10 degrees F it was starting to freeze together, and the wind was rising. Not an immediate threat but it was impossible to get to work sites in a reasonable time; unless it warms up next week the place may become impassable.
The irony of all of this is that the big icebergs and floes streaming southward out of the Arctic Ocean and blocking the strait may be an indicator of Arctic warming. Although icebergs are not unknown here, those who have been on past expeditions did not report so many. Normally they tend to stay put up in the Arctic, but we think maybe the ice there has loosened up enough that the bergs are free to drift southward. We are not sure of this; will have to check satellite images and commentaries from ice tracking programs when we get home. It could just be random weather this year – we know that year-to-year variations do not indicate trends. But it is certainly not a cooling trend, because we measured the warmest subsurface water ever recorded in the region, and this subsurface water tends to filter out the random short-term noise. Admittedly there is not much previous information – as far as we know just a few measurements in 2003, 2007, 2009, and 2012. Now we have measured it more completely and know where the water flows, what its properties are, and how it gets into Petermann Fjord, constrained by various shallow sills and (within the basin) by relatively narrow deeper canyons we have mapped. After we get home, we are optimistic that our sediment samples will provide information about much longer-term and larger scale changes in both the ice and the watermasses. This will take some time and careful lab work to sort out.
After leaving the Petermann region we hoped to work a bit further south, perhaps coring and sampling the water, but the wind was too high — about 50 knots out of the north and very cold, with new snow all over the mountains in Canada to our right, and a bit also on Greenland to our left. Beautiful as scenery, but not great for getting work done. So with that tailwind we kept going south, surveying a bit within Nares Strait looking for evidence on the sea floor for lineations left by past ice. We hid behind a headland just north of Humboldt Glacier, and got a helicopter out to sample boulders on the islands in Nares Strait. hese are glacial “erratics” – out-of-place granite boulders sitting anomalously on a landscape of limestone. There is no way the granite could have come from a local source, and boulders don’t fly, so the glacier must have dropped them. Dating these boulders will confirm when the thick ice left Nares Strait.
Our next steps include dealing with the fuel caches they left for CBS News and for emergency use as needed – a trail of breadcrumbs for helicopter flights back to Thule if needed. All cache sites will be left in good shape and fully documented.
So… now I’m focused on writing reports, packing samples and lab gear, cleaning both labs and my room, doing laundry… mostly mundane stuff. It is about a three-day trip for Oden to get back to Thule, passing the huge ice front of the Humboldt Glacier. During this transit we arranged for two or three science talks per day on our results; some are comments from the senior scientists, but we are trying to give the younger scientists a chance to speak — good practice putting together a story on the fly. As we approach Thule we will switch from UTC time to local Greenland time. We can’t go to the pier (too shallow for this ship) so we will unload the ship by crane lifting our luggage onto a small boat and ferrying everyone over to land in a launch. From there we will take a military flight south to Kangerlussuaq, where we will stay two nights waiting for another military flight to New York, and from there on the same day we move on to Oregon.