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Arctic Geotraces 2015 Letter from Jim Swift, CTD/hydrographic Scientist, 10 Oct 12, 2015

HLY1502 letter 10 from Jim Swift

final letter from sea

Sunday, 11 October 2015, 3:00 pm, local date and time (2300 11 October UTC)

4.3°N, 166.4°W (about 26 miles north of Dutch Harbor in the Aleutian Islands)

air 6 degC / 43 degF

water 9 degC / 48 degF

wind 26 knots from W

on final approach to Dutch Harbor, Alaska

Dear Family, Friends, and Colleagues,

Our final days of oceanographic work on HLY-1502 continued the wait-for-a- weather-window theme of the previous week, although science operations transpired without incident during the times we were able to work. Working over the stern - required at Geotraces station locations - was restricted to wind and sea conditions unlikely to result in problems with the oceanographic cables, and with fall storms in the area those times were fewer than hoped. But Geotraces did manage a sequence of three continental slope stations (at 3465, 1000, and 85 meters water depth) and a 35 meter deep continental shelf station. The CTD/rosette casts my team carries out use the starboard A-frame. From there we can work in a somewhat broader weather window and so we were able to add casts at 2600, 1600, 500, 300, 160, and 68 meters deep. Overall these sum to a fine cross-section of measurements over the abrupt Canada Basin

  • continental slope - Beaufort shelf transitions.

The ODF CTD/rosette program (my program) went well right to the end. Over the course of a 64-day expedition there were very few rosette problems, the analysts maintained outstanding data quality (there were only a few nutrients or oxygen values coded ‘bad’ out of thousands the entire cruise), and there was excellent attention to data processing. The CTD/hydrographic data the science teams will carry home is ready for initial research use, with little change expected from the few final data processing steps remaining ashore.

Following completion of the oceanographic work, after waiting a bit for acceptable flying weather, two officials from the Department of Homeland Security (which includes the Coast Guard) were brought out by helicopter from Barrow to ride the ship to Dutch Harbor. The next day a crew member was flown ashore for medical attention, and then the Healy began a fast transit south. (See photo of helicopter operations.) Winds have often been above 20 knots, and there was a stretch where sustained winds of about 40 knots were recorded, but fortune has smiled upon us: the winds have been behind us, giving us a fast and relatively comfortable “downhill” ride almost all the way.

In the early parts of the past week, there were partly clear nights several times, with active auroras. Even the somewhat rarer pinkish aurora was seen (see attached photo).

Last night the science team cooked dinner. The Healy has an excellent galley staff, but we held our own with a meal of coq au vin (for which we used the last of the ship’s onions and carrots), rice, grilled corn, macaroni and cheese, dinner rolls (which I helped make), and ice cream cookie sandwiches. It was a fun time for the science team and all hands seemed to enjoy the dinner. [If you are wondering about the “coq au vin” on a “dry” ship, note that the Healy’s cooking wine is a salt-added commercial product made for these situations. I joked that the cooking wine was only a little less salty (15 on the salinity scale) than some of the surface waters we ran into (just over 20 on the same scale).]

We should arrive in port early this evening, a half day ahead of schedule (thanks to those tail winds). The Dutch Harbor port period will be very busy for most on the science team, who are leaving the ship. Nearly all unloading will take place when the ship returns to Seattle in November, but all labs must be stripped, packed, and cleaned, and every item left on board must be securely tied down for the Healy’s possibly rough transit across the Gulf of Alaska after it leaves Dutch Harbor.

I have never seen one of the TV fishing shows that features Dutch Harbor so I did not realize until we were told today that we will see a very much busier Dutch Harbor than we left two months ago. That was the slow time - who knew? The crab fishing season starts mid-week and we were told the town is teeming, the bars are full (including with some looking for a fight), and that we should take special care. We had all been looking forward to socializing - well, we are not looking for trouble so maybe it won’t find us.

A wide range of scientific inquiry will be made possible by the new repeat hydrography data. Because this is intended for a general audience I will say simply that my program’s results bear strongly on aspects of the ocean such as ocean warming, ocean acidification, increased stratification of the oceans, and large scale shifts of the distribution of waters away from their source regions.

All of this would not have been possible without the enthusiastic and capable support provided by Captain Hamilton, the officers & crew of USCGC Healy, and the science teams. I owe them and the US Coast Guard and National Science Foundation my heartfelt thanks for making these outstanding sections across the Makarov and Canada basins possible.

A few reflections in closing…

I have long been interested in the polar regions, and I am also drawn to hydrography, a word oceanographers use to encompass both the measurement of temperature, salinity, and other properties of seawater and also the interpretation of those data to describe aspects of the nature and circulation of ocean waters. A stroke of great good fortune brought me to Knut Aagaard, my graduate advisor at the University of Washington, who remains my oceanographic mentor and stout friend. And Joe Reid generously guided and supported me at the Scripps Institution of Oceanography, providing me not only the opportunity to work with him and his group, but also to study the World Ocean itself. I have since enjoyed an exciting career working with visionary scientists and supportive ship operators, and been honored to participate on great voyages with wonderfully talented technical teams, thinking especially of the SIO Oceanographic Data Facility measurement specialists to whom I owe so much.

The plans for USCGC Healy Cruise 1502 represented a once in a lifetime opportunity to measure and interpret change in some of the world’s waters I love best. To have now sailed the oceanographically-rich track on which we engaged has been a dream come true, and, seeing this is intended to be my final oceanographic cruise, a fitting finale to the seagoing aspect of my career.

That the National Science Foundation and other Federal agencies which support science at sea, the Scripps Institution of Oceanography, and my family have so wholeheartedly supported me on these endeavors for so many years is a great privilege for which I will always be indebted. I enjoy an abiding satisfaction that comes from doing something worthwhile, and doing it well.

Jim Swift

Research Oceanographer

UCSD Scripps Institution of Oceanography

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Arctic Geotraces 2015 Weekly Science Report from Jim Swift, CTD/hydrographic Scientist, Week 9 Oct 12, 2015

USCGC Healy Cruise HLY-1502

US Arctic Geotraces

Weekly CTD/Hydrographic Team Report 09

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

Sunday, 11 October 2015, 3:00 pm, local date and time (2300 11 October UTC)

54.3°N, 166.4°W (about 26 miles north of Dutch Harbor in the Aleutian Islands)

air 6 degC / 43 degF

water 9 degC / 48 degF

wind 26 knots from W

on final approach to Dutch Harbor, Alaska

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,

Our final days of station work on HLY-1502 continued the wait-for-a-weather- window theme of the previous week, although science operations transpired without incident during the times we were able to work. Working over the stern

  • required at Geotraces stations - was restricted to wind and sea conditions unlikely to result in problems with the oceanographic cables, and with fall storms in the area those times were fewer than hoped. But Geotraces did manage a sequence of three slope stations (≈ 3465, 1000, and 85 meters) and a 35 meter shelf station. Repeat hydrography, which uses the starboard A-frame and could work in a somewhat broader weather window, added casts at 2600, 1600, 500, 300, 160, and 68 meters. These stations sum to a fine hydrographic section across the abrupt Canada Basin - slope - Beaufort shelf transitions.

The ODF CTD/rosette program went well right to the end. Over the course of a 64-day expedition there were very few rosette problems, the analysts maintained outstanding data quality (there were only a few nutrients or oxygen values coded ‘bad’ the entire cruise), and there was excellent attention to data processing. The CTD/hydrographic data the science teams will carry home is ready for initial research use, with little change expected from the few final data processing steps remaining ashore.

Following completion of the CTD/hydrographic work, after waiting a bit for acceptable flying weather, two officials from the Department of Homeland Security (which includes the Coast Guard) were brought out by helicopter from Barrow to ride the ship to Dutch Harbor. The next day a crew member was flown ashore for medical attention, and then the Healy began a fast transit to Dutch Harbor. Winds have often been above 20 knots, and there was a stretch where sustained winds of about 40 knots were recorded, but fortune has smiled upon us: the winds have been behind us, giving us a fast and relatively comfortable “downhill” ride almost all the way.

In the early parts of the past week, there were partly clear nights several times, with active auroras. Even the rarer pinkish aurora was seen (see attached photo).

Last night the science team cooked dinner. The Healy has an excellent galley staff, but we held our own with a meal of coq au vin (for which we used the last of the ship’s onions and carrots), rice, grilled corn, macaroni and cheese, dinner rolls, and ice cream cookie sandwiches. It was a fun time for the science team and all hands seemed to enjoy the dinner.

We should arrive in port early this evening, a half day a‹head of schedule (thanks to those tail winds). The Dutch Harbor port period will be very busy for most on the science team, who are leaving the ship. Nearly all unloading will take place when the ship returns to Seattle in November.

A wide range of scientific inquiry will be made possible by the new repeat hydrography data. Preliminary analyses show that the mean temperatures in the layer defined between the sigma-0 27.8 and 28.05 isopycnals - which corresponds roughly to the density of the northern source of Denmark Strait Overflow Water - warmed considerably between 1994 and 2015 over the Chukchi Borderlands and in Makarov Basin, but there was little change between 2005 and 2015 from the Southern Canada Basin to the crest of the Alpha Ridge.

There were some strong changes in the halocline waters on the outbound section. For example the maximum in dissolved silicate, which lies in the halocline (roughly 150 meters) and well above the DSOW layer, showed large Makarov Basin 1994 to 2015 cruise-to-cruise differences, but small changes over 2005 to 2015 in the Canada Basin. And as is known from other recent studies, surface salinities over the two Canadian sector basins are now much fresher than they were in the past, yet we found that the lower intermediate water salinities are often a little higher now. There are exciting results in the ocean carbon and CFC/SF6 data as well.

All of this would not have been possible without the enthusiastic and capable support provided by Captain Hamilton, the officers & crew of USCGC Healy, and the science teams. I owe them and the US Coast Guard and National Science Foundation my heartfelt thanks for making these outstanding sections across the Makarov and Canada basins possible.

A few reflections in closing…

I have long been interested in the polar regions, and I am also drawn to hydrography, a word oceanographers use to encompass both the measurement of temperature, salinity, and other properties of seawater and also the interpretation of those data to describe aspects of the nature and circulation of ocean waters. A stroke of great good fortune brought me to Knut Aagaard, my graduate advisor at the University of Washington, who remains my oceanographic mentor and stout friend. And Joe Reid generously guided and supported me at the Scripps Institution of Oceanography, providing me not only the opportunity to work with him and his group, but also to study the World Ocean itself. I have since enjoyed an exciting career working with visionary scientists and supportive ship operators, and been honored to participate on great voyages with wonderfully talented technical teams, thinking especially of the SIO Oceanographic Data Facility measurement specialists to whom I owe so much.

The plans for USCGC Healy Cruise 1502 represented a once in a lifetime opportunity to measure and interpret change in some of the world’s waters I love best. To have now sailed the oceanographically-rich track on which we engaged has been a dream come true, and, seeing this is intended to be my final oceanographic cruise, a fitting finale to the seagoing aspect of my career.

That the National Science Foundation and other Federal agencies which support science at sea, the Scripps Institution of Oceanography, and my family have so wholeheartedly supported me on these endeavors for so many years is a great privilege for which I will always be indebted. I enjoy an abiding satisfaction that comes from doing something worthwhile, and doing it well.

Jim Swift

Research Oceanographer

UCSD Scripps Institution of Oceanography

Read More

Arctic Geotraces 2015 Weekly Science Report from Jim Swift, CTD/hydrographic Scientist, Week 8 Oct 5, 2015

USCGC Healy Cruise HLY-1502

US Arctic Geotraces

Weekly CTD/Hydrographic Team Report 08

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

Sunday, 04 October 2015, 7:30 pm, local date and time (0330 05 October UTC)

73°N, 158.8°W (on the Beaufort slope)

air -4 degC / 25 degF

water -0.5 degC / 31 degF

wind 1-2 knots from ENE

on station 060 (a Geotraces ‘slope’ station)

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,

This week started out rough for the expedition’s science programs, with Geotraces hit especially hard. Reversing the order of the cruise plan worked out well for most of the cruise, enabling excellent Arctic Ocean spatial coverage for example. But one of the acknowledged risks was the degree to which fall storms would undermine the ability to carry out the final stations when the ship was in open water late in the season, just as we are now. Although we arrived in the southern Canada Basin with equipment working well, and what seemed to be a fine amount of time to do the scheduled work (I am not privy to the cruise time line, however), a series of low pressure systems has disrupted station work and led to damage to two of the three oceanographic cables used this cruise: the trawl wire experienced damage some hundreds of meters above the termination and the Vectran synthetic cable required for the trace metal rosette program had to be inspected for possible damage about 1000 meters above the termination. Both of the cables are used over the stern A-frame and both were involved in very high wire angle situations during casts the same day of worsening weather during the past week. No equipment was lost. The trawl wire was quickly put back into service, and the Vectran cable issue also was not a special problem, but the core issue remains that stormy weather makes for rough conditions, affecting most severely our science operations over the stern. We lost several days of stern operations due to weather, and this has put a dent in plans for the final thrust of the science program, which focuses on examining the basin-to-slope-to-shelf transition in the Southern Canada Basin. By the time of next week’s report all this will have been settled one way or the other.

One other cable problem, not associated with bad weather, occurred a few hours ago: We lower the big 36x10-liter ODF rosette to within 10 meters of the bottom, take our first water sample, then haul it up and stop to take other water samples at other levels. When it came time to haul up from near the bottom, the winch went down instead of up and quickly lowered the rosette onto the bottom. No damage was done to the rosette, but when tension is taken off the CTD cable like that, the cable kinks due to accumulated torque, so after the rosette was back on deck we had to cut off the kinked part and make a new termination. As a result all three of our oceanographic cables have had new terminations since my previous report.

Although we are now in good weather, storms continue to haunt us with the next one due some time Monday. If it is bad enough and lasts long enough, that might be the end of science operations on the Canada Basin section because at some point we must begin heading for Dutch Harbor.

Fair weather windows can be short, making science planning less orderly than the norm preferred by the Coast Guard, which prefers a firm plan for the next 24 hours at 6:30 pm each day. There is also the matter that bathymetric charts for this region are inaccurate whereas we need to stop and do stations at scientifically-chosen isobaths, rather than assign in advance firm positions as favored by the Coast Guard. The Coast Guard has patiently worked this out with us, and now we are working well together on this.

Meanwhile, the CTD/hydrographic measurements and data processing for both Geotraces and repeat hydrography continue to go very well when we are able to work. Deck operations are smooth and quick, the CTD works well in the just- below-freezing (as opposed to deeper cold) weather of the past, and all hydro team lab systems continue excellent performance. The CFC and ocean carbon teams have been able to do full profiles, generating a treasure of data for repeat hydrography.

Here in the Canada Basin we have replicated a significant portion of the section done from the Swedish icebreaker Oden in 2005. Temperature comparisons show that the mid-depth layers have warmed since 2005 and that the upper layer has greatly freshened. These results are overall similar to the 2015-minus-1994 Makarov Basin differences reported earlier this cruise, demonstrating the widespread nature of these Arctic Ocean changes.

I mentioned in last week’s report that we were going to be looking for intermediate depth waters from the Chukchi Borderlands / Northwind Ridge boundary spreading into the Canada Basin interior. This week we did see boundary-like waters along our transect, in the same latitude range where they have been observed previously. There are also clear indications that the shallower halocline silicate maximum layer is being swept into the Canada Basin from that same Chukchi Borderland / Northwind Ridge area.

One way or the other our science work ends in a few days. We are tired, but not tired out. We are certainly not hungry, not with the excellent food the galley continues to provide. We enjoy working with our Coast Guard comrades, who treat us very well indeed. But we are all - Coast Guard and science teams alike - ready to finish up and head for port.

Saving a nice moment for last: We had a clear night with an aurora! Cory Mendenhall, the ship’s public affairs officer, captured a wonderful photo (attached) from the Healy’s helicopter pad, looking forward towards the hangar, with the ship’s red night lights glowing and the moon illuminating the sky beyond, auroral drapery shifting, changing, beautiful.