USCGC Healy Cruise HLY-1502

US Arctic Geotraces

Weekly CTD/Hydrographic Team Report 04

from Jim Swift, UCSD/SIO, CTD/hydro team scientific leader at sea

Monday, 07 September 2015, 7:00 pm, local date and time (2100 07 September UTC)

90°N (in the Amundsen Basin of the Arctic Ocean)

air -3.8 degC / 25 degF

water -1.4 degC / 29 degF

wind 16 knots from N (not certain what the “N” on the meteorological display means, considering our location!)

on station 34, at the North Pole

Note: This is a hydrography-oriented report from Jim Swift, who is working with the SIO Oceanographic Data Facility (ODF) CTD/hydrographic team on the US Geotraces Arctic Ocean expedition led by Dr. David Kadko, FIU, chief scientist. This is not a report from Dr. Kadko or the other science teams.

Dear Colleagues,

Last week we completed all planned station of the reoccupation of the Makarov Basin transect carried out in 1994 by the Canadian icebreaker Louis S. St- Laurent and the US Coast Guard icebreaker Polar Sea. This was one of two principal goals for the repeat hydrography team on board the Healy. Preliminary hydrographic results include a huge freshening of the upper layer, re-extension of the low oxygen, high silicate halocline across the Makarov Basin, and a basin-wide warming of the Atlantic layer. CTD/hydrographic data quality is excellent.

The ship then continued to head north…

As the US Coast Guard has reported, at 7:47 ship’s time Saturday, September 5th, USCGC Healy became the first US ship to reach the North Pole unaccompanied by another icebreaker. It was also a milestone of sorts for me, because there have been three scientific crossings by surface ship from Bering Strait to the Pole - 1994, 2005, and 2015 - and I was on all three, doing similar work each cruise (and thus learning about ocean change in this remote part of the World Ocean).

My informal assessment of the Arctic Ocean sea ice we have been traversing continues in the same vein as during the past two weeks: much of the ice appears to be first-year ice. I have observed that extra power appears to have been required remarkably few times for an expedition working in the central Arctic Ocean. This is very different from the experiences we had with the ice 10 and 21 years ago.

There was a large lead quite close to the Pole, so we first carried out a long, 8-cast Geotraces science station. On our deep cast we attached several net bags full of decorated Styrofoam cups which were shrunk by the more than 400 atmospheres of pressure they encountered, making nice souvenirs. We did face colder weather conditions than I expected yesterday because a high pressure system built up, and with it came clear skies and a still, dry atmosphere, causing air temperatures to dip down to -14°C (7°F) when we were working. This was cold enough to freeze up our CTD in the time it took to move it from the sampling room and deploy it - it took nearly 20 minutes in near- freezing ocean waters to thaw it. This freezing caused some CTD damage, but we were able to complete the cast and later replace damaged parts. Freezing was an annoyance during sampling, too. We anticipate colder conditions later this month, so we are installing a heater-fan to blow warm air over the rosette when it is outside on deck.

After we were done with the science work the captain looked for an ice floe nearby that was large and rugged enough for an excursion onto the ice which began with a recognition and awards ceremony on the ice and a group photo. Then came fun for all - known as “ice liberty” - a chance to play and let loose on a couple meters of ice floating on more than 4000 meters of water. Bill Landing (FSU), the co-chief scientist, played Christmas songs on his saxophone. Santa visited, too.

The North Pole is a point on the globe, a spot similar to many other places in the Arctic Ocean. But it seems to be a magnetic pole of sorts considering how it attracts steel ships. The Canadian icebreakers Louis S. St-Laurent and Terry Fox passed us southbound as we were on the final stretch to the Pole, and the German polar research ship Polarstern pulled up near us today as we were preparing to leave. We held up, re-lowered the brow, and each ship hosted visits - a good time was had by all. In the next year measurements from all three nations will be compared. In our immediate future, however, we have resumed our station work, heading south to Alaska.

All is well.

Jim Swift

Research Oceanographer

UCSD Scripps Institution of Oceanography

Addendum #1 to weekly report from North Pole

The email queue has improved to the point where I can send a couple of photos from the North Pole visit.

This photo shows the bow of the Healy at the North Pole. Note the partially refrozen lead around the ship, and the low sun angle. (At the Pole the sun goes around and around, with its elevation above the horizon - and below in winter -‹ a function of the date; we are closing in on the Equinox, at which date the sun would go around right at the horizon, if viewed from the pole.) Note also the rainbow-like “sun dog” caused by ice crystals in the air. Photo credit: Cory Mendenhall, US Coast Guard.

This photo shows co-chief scientist Bill Landing (Dr. William Landing; Florida State University), playing the saxophone (Christmas songs) on the ice at the North Pole. Photo credit: Katlin Bowman, UC Santa Cruz.