US GO-SHIP is part of the international GO-SHIP network of sustained hydrographic sections, supporting physical oceanography, the carbon cycle, and marine biogeochemistry and ecosystems. The US program is sponsored by US CLIVAR and OCB. Funded by the National Science Foundation and NOAA.

News

S4P: 21 APR 2011 (LETTER) Oct 2, 2013

Dear Family, Friends, and Colleagues,

Homeward bound!

At 05:25 local time on Tuesday, 19 April 2011, the rosette from station 140, the easternmost station we planned, and the last one on CLIVAR S04P, was brought into the Baltic Room. This completed the over-the-side work for our cruise, though it took a day to analyze the samples that we backlogged as we crossed the eastern boundary of our study area. We arrived at the eastern end a little earlier than expected due to an unprecedented (for this cruise) eight day string of days with light winds, plus our equipment worked nearly flawlessly.

So what did we do next? We went on an oceanographic treasure hunt! Believe it or not, five days earlier a satellite had reported to its base station that a 400 meter long biophysical mooring for Dr. Richard Limeburner (Woods Hole), deployed in 450 meters of water more than ten years ago by Jim Ryder (the mooring tech on our cruise), but lost in 2001 when it failed to rise to the surface when triggered to do so, had all of a sudden come to the surface and contacted the satellite. (Good batteries!) The location was only about 8 hours away. So after our final station we motored over to its last reported location and - voila! - there it was! Jim, the RPSC marine techs, and our students and other helpers then set to work, recovering the entire string of instruments, covered with ten years of marine growth. Everything was cleaned and will be returned to Dr. Limeburner. What a wild coincidence!

We are now on our way to Punta Arenas, Chile, which is our end port for this long cruise. We’re getting a bit of a weather blast today - after all, this is Drake Passage, infamous for its heavy weather - yet we are actually ahead of schedule and are arriving a little early. We still will not be able to begin our unloading until Monday, due to Easter.

Tonight we will hold a little variety show on the ship, featuring skits and music from our “polliwogs” (those for whom this was their first Antarctic crossing) plus some of the “red noses”. I’ll even toot the bassoon a bit. There will be a traditional induction for the polliwogs tomorrow morning.

And that’s just about that for this cruise. It’s been a long haul - 64 days at sea without a port stop is a new record for most if not all of us. But we achieved our scientific objectives (except for the iced-up southern end of P18 and mooring recoveries there), and enjoyed a safe and productive time at sea. We are very grateful to our shipmates from Edison Chouest Offshore, who operate the Nathaniel B. Palmer and support us and our science so well, thankful for our support from our seven colleagues from Raytheon Polar Services Corporation, and deeply appreciative of our support for this venture from the National Science Foundation, the National Oceanic and Atmospheric Administration, and the National Aeronautics and Space Administration.

We did it!

All is well on the Nathaniel B. Palmer.

Jim Swift
Chief Scientist
NBP-1102 / S04P

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S4P: 14 APR 2011 (REPORT) Oct 2, 2013

Not everything on a research cruise goes as planned or hoped. We headed south last Saturday on a dual-purpose mission. The NOAA research ship Ronald Brown had stopped southward progress at an iceberg corridor near 69°S in 2008 when doing the north-to-south “P18” cruise for our long-term program. We hoped to extend their work south to the Antarctic continental shelf break somewhere near 100°W. There was also the issue of mooring recoveries in that same general area for LDEO investigator Stan Jacobs. We knew from satellite images sent to the ship that sea ice covered nearly 100% of the surface in the area, but the Palmer can handle sea ice if not too thick. Still, we decided to first see how long it took us to get to our desired end point near the shelf break, allotting a certain maximum amount of time to icebreaking (in accord with our master plan for the remainder of the cruise), at which point we would know how much time we had for our work plus the icebreaking and steaming as we headed back north. Admittedly success with the mooring recoveries seemed remote because those could not be done in full ice cover, but one never knows until trying.

We reached the ice edge at the expected point along the track and progressed well at first. Then the going got tough, not so much because of ice thickness as because of the large amount of snow on the ice. Snow rubs against the ship’s hull much like sand would, sapping power and momentum as the ship presses forward. Only about 20 miles into the ice (20 miles straight line, but many more miles as we worked around large snow-covered floes) the Captain and Ice Pilot decided enough was enough. In the morning conditions looked no better, so we took advantage of being in a large floe to have a brief ice party for those on board, i.e. a chance to be on the ice a bit. We had a good time - playing soccer, walking around, playing in the snow. After everybody was back aboard we pulled into a nearby opening in the ice and did a CTD cast. That cast showed nothing remarkable compared to nearby data from 2008. There we were, nearly 50 miles from our targets - either the shelf break or Jacobs’ moorings - but we could not go further south. There being no point to lingering, we headed back north to the main 67°S line.

Thus we were not able to extend the P18 line south through the ice to the continental shelf break, and we were not able to recover any of Stan Jacobs’ ice-covered moorings. The only benefit of the way this worked out was that we spent one day’s time and fuel less on the excursion than planned so now have some weather time in the schedule before the end of science activities in five and a half days. This should enable us to not only reach the eastern end of the S04P section, but also to sample its eastern boundary region appropriately.

We always enjoy our trips through the ice. We did not see many penguins this time (though there were a few, including Emperor penguins) but there were many seals hauled out onto the thicker floes. The leads (openings in the ice) are freezing over and there are many 4 to 10-foot holes punched up through the thin ice. The culprits? Orcas (Killer Whales) on the lookout for seals on the thicker ice nearby. Jim saw a pair of them stick their heads out of one of the holes to take a look-see.

The weather has been unusually good. That may well change, but we are back on “the line” and for now we are mowing down the final stations one by one, making very good progress. Everyone has their sights set on keeping steady and focused: Get the job done. Then go to port!

All is well on the Nathaniel B. Palmer.

Jim and Alex

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S4P: 14 APR 2011 (LETTER) Oct 2, 2013

Dear Family, Friends, and Colleagues,

The PolarTREC program is sponsoring a live event THURSDAY (April 14th) with Juan Botella on the satellite phone along with an on-line presentation. Anyone is welcome to participate on line, but registration is required. See the announcement below.

Jim Swift

PolarTREC Announcement:

Join us for the upcoming real-time PolarConnect event with PolarTREC teacher, Juan Botella, and scientists of the Seawater Property Changes in the Southern Ocean who are on board the Icebreaker N.B. Palmer of the coast of Antarctica! Participants will learn more about the oceanography of the Antarctic and how scientists are studying this unique place.

Anyone is welcome to participate: classrooms, teachers, or just interested members of the public. These events are hosted through the PolarTREC PolarConnect (formerly Live from IPY!) program, and participants will have a chance to learn from the scientists, ask questions, and chat with others during the presentation.

EVENT DETAILS:
DATE: Thursday, 14 April 2011
TIME: 1:00 PM AST (2:00 PM PST, 3:00 PM MST, 4:00 PM CST, 5:00 PM EST)

Registration: To register (required) and to receive instructions on how to join, go to: http://www.polartrec.com/polar-connect/register

For more information about the science that Mr. Botella is involved in, please read his journals at: <http://www.polartrec.com/expeditions/seawater-property- changes-in-the-southern-ocean>

Questions?
Visit: www.polartrec.com
Contact us at: info@arcus.org or 907-474-1600

PolarTREC is funded by the National Science Foundation Office of Polar Programs and managed by the Arctic Research Consortium of the United States (ARCUS), 3535 College Road, Suite #101, Fairbanks, AK U.S.A. 99709-3710. www.arcus.org

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S4P: 13 APR 2011 (LETTER) Oct 2, 2013

Dear Family, Friends, and Colleagues,

Not everything on a research cruise goes as planned or hoped. We headed south last Saturday on a dual-purpose mission. The NOAA research ship Ronald Brown had reached the ice edge in 2007 doing the “P18” cruise for our long-term program, and we hoped to extend their work south to the Antarctic continental shelf break somewhere near 100°W. There was also the issue of mooring recoveries in that same general area for LDEO investigator Stan Jacobs. We knew from satellite images sent to the ship that sea ice covered nearly 100% of the surface in the area, but the Palmer can handle sea ice if not too thick. Still, we decided to first see how long it took us to get to our desired end point, allotting a certain maximum amount of time to icebreaking (in accord with our master plan for the remainder of the cruise), at which point we would know how much time we had for our work plus the icebreaking and steaming as we headed back north. Admittedly success with the mooring recoveries seemed remote because those could not be done in full ice cover, but one never knows until trying.

We reached the ice edge at the expected point along the track and progressed well at first. Then the going got tough, not so much because of ice thickness as because of the large amount of snow on the ice. Snow rubs against the ship’s hull much like sand would, sapping power and momentum as the ship presses forward. Only about 20 miles into the ice (20 miles straight line, but many more miles as we worked around large snow-covered floes) the Captain and Ice Pilot decided enough was enough. In the morning nothing looked any better, so we took advantage of being in a large floe to have an ice party - free time for those on board to be on the ice a bit. Everybody had a good time - playing soccer, walking around, playing in the snow. After everybody was back aboard we pulled into an opening in the ice and did a CTD cast. That cast showed nothing remarkable compared to nearby data from 2007. There we were, nearly 50 miles from our targets - either the shelf break or Jacobs’ moorings - but we could not go further. There being no point to lingering, we headed back north to the main 67°S line.

Thus we were not able to extend the P18 line south through the ice to the Continent and we were not able to recover any of Stan Jacobs’ ice-covered moorings. The only benefit of the way this worked out was that we spent at least one day less on the excursion than planned so now have about a day’s worth of weather time in the schedule between now and the end of science activities five and a half days from now. This should enable us to reach the eastern end of the west-to-east section which is one of our main focus areas.

We always enjoy our trips through the ice. We did not see many penguins this time (though there were a few, including Emperor penguins) but there were many seals hauled out onto the thicker floes. The leads (openings in the ice) are freezing over and there are many 4 to 10-foot holes punched up through the thin ice. The culprits? Orcas (Killer Whales) on the lookout for seals on the thicker ice nearby. I saw a pair of them stick their heads out of one of the holes to take a look-see.

The weather has been unusually good. That may well change, but we are back on “the line” and for now we are mowing down the final stations one by one, making very good progress. Everyone has their sights set on keeping steady and focused: Get the job done. Then go to port!

All is well on the Nathaniel B. Palmer.

Jim Swift
Chief Scientist
NBP-1102 / S04P

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S4P: 07 APR 2011 (REPORT) Oct 2, 2013

We have increased our basic CTD station spacing to 60 nautical miles, from the original 30 nautical miles. We kept to 30 over the core (and highest priority) part of the cruise plan. We knew, however, that when we crossed into the Antarctic Circumpolar Current, which we are now sailing in and along, there was little oceanographic damage switching to 60-mile spacing, which helps save time. The station plan includes runs to the continental slope with more closely spaced stations at the ends of the P18 and S4P lines. Ice conditions at the end of the P18 line (see attached file for today’s ice map) may allow us to make it to the shelf break, perhaps a little east of the intended line, within the time we will allot to that portion of the cruise plan.

The pace in the labs is now a little more relaxed. With a plan in place regarding how we intend to complete the measurement program (within the next two weeks), everyone is focused on simply getting the job done.

Temperature and salinity differences with the 1992 Ioffe occupation of S04P continue in a similar vein to those reported earlier: away from the western boundary, the bulk of the water column is a little warmer and possibly slightly saltier now than measured in 1992.

A major activity this week was the deployment of a 4 km string of moored instruments at a specified spot in the ocean for Xiaojun Yuan (Columbia/LDEO) and Janet Sprintall (SIO). Neither PI was on board, but because WHOI mooring expert Jim Ryder was along, they knew - quite correctly - that their project was in great hands. The specifications called for the top float of the mooring to be 100 meters below the sea surface - in ca. 4500 meters of water - plus the mooring needed to be in an area where the bottom was flat, and had to be deployed in reasonably good weather. We used the Palmer’s multi-beam bathymetric mapping system (managed by Chris Linden, RPSC) to map the ocean floor, then we did a CTD cast at the most likely looking mooring deployment spot to measure the water characteristics and verify the bottom depth. There were also a host of XBT casts and one more CTD cast associated with the mooring science program, not to mention the long deployment itself. Add a day of time lost to bad weather before mooring deployment, and you can see why this was quite an operation, and one we are glad to have completed successfully and now have behind us.

A highlight for the science team was tours of the Palmer’s engine spaces this week by Chief Engineer Johnny Pierce (“JP”) and his expert team of engineers. With two of the four large marine diesel engines powered up plus some of the electrical generator diesels, of course hearing protection was needed, and there are hot/dangerous spots to avoid. But ordinary clothes are fine - nothing will get dirty during a tour to the engineers’ nearly spotless work place, as clean and as orderly as can be. Wow!

Holidays can be fun on board, so April 1st got some special attention. Even better, some of us who were “fooled” forgot that it was April 1st, adding to the joy of the conspirators and the fun had by all. Check out Juan’s blog for the fun.

We’re a relaxed bunch, well-fed, tired of stormy weather, happy for the present good weather, and working together to get the job done.

All is well on the Nathaniel B. Palmer.

Jim and Alex

Included with this email:

”” shows the planned P18S track to (and slightly beyond) the shelf break along with the 06April2011 ice conditions. If conditions stay much the same, our “P18S” track would run slightly east of that shown, in more favorable ice conditions. Ice coverage is currently ca. 100% in the area of Stan Jacobs’ moorings. We are not equipped to recover moorings in ice-covered waters.

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S4P: 06 APR 2011 (LETTER) Oct 2, 2013

Dear Family, Friends, and Colleagues,

We have increased our basic CTD station spacing to 60 nautical miles, from the original 30 nautical miles. We kept to 30 over the core (and highest priority) part of the cruise plan. We knew, however, that when we crossed into the Antarctic Circumpolar Current, which we are now sailing in and along, there was little oceanographic damage switching to 60-mile spacing, which helps save some time. The pace in the labs is now a little more relaxed. With a plan in place regarding how we intend to complete the measurement program (within the next two weeks), everyone is focused on simply getting the job done.

Holidays can be fun on board. Many of us have celebrated nearly every holiday at sea one time or another (Christmas and New Years included). We’re a bit short of holidays this cruise, so April 1st got some special attention. Even better, some of us who were “fooled” forgot that it was April 1st, adding to the joy of the conspirators and the fun had by all. Yes, they got me, and good, by pasting photos of my head on the body-builder posters in the gym. Chris Measures was genuinely alarmed when the deck tech told him “blue sparks” were coming out of his CTD when he turned it on. And so on. Check out Juan’s blog for more of the fun.

The Big Activity this week was deployment of a more than 4000-meter long string of moored instruments - current meters, CTDs, and the like - with floats, releases, and anchor, at a specified spot in the ocean for Xiaojun Yuan (Columbia/LDEO) and Janet Sprintall (SIO). Neither PI was on board, but because world-class mooring expert Jim Ryder (Woods Hole) was along, they knew

  • quite correctly - that their project was in great hands (See photos above). The specifications called for the top float of the mooring to be 100 meters below the sea surface - in ca. 4500 meters of water - so it was important to know very well the depth to the bottom there (so that the mooring cable length could be adjusted), plus the mooring needed to be in an area where the bottom was flat, and had to be deployed in reasonably good weather. We used the Palmer’s multi-beam bathymetric mapping system (managed by Chris Linden, RPSC) to map the bottom, then we did a CTD cast at the most likely looking mooring-deployment spot to measure the water characteristics and verify the bottom depth. There were also other CTD casts and a host of XBT casts associated with the mooring, not to mention the long deployment itself. Add a day of time lost to bad weather, and you can see why this was quite an operation, and one we are glad to have completed successfully and now have behind us.

A highlight for the science team was tours of the Palmer’s engine spaces this week by Chief Engineer Johnny Pierce (“JP”) and his expert team of engineers. With two of the four large marine diesel engines powered up plus some of the electrical generator diesels, of course hearing protection was needed, and there are hot/dangerous spots to watch out for. But ordinary clothes are fine

  • nothing will get dirty during a tour to the engineers’ nearly spotless work place, as clean and as orderly as can be. Wow!

During the mooring-related activities the Palmer crossed (and recrossed) the Antarctic Circle, which we had been south of until then. There is a long marine tradition of marking such events with “initiations” of the “polliwogs” who have crossed for the first time. Of course these affairs are now voluntary and fun (well, mostly). At any rate, our polliwogs are on notice that something is up in their future, and volunteers among the resident “red-noses” (those initiated in the past) are rumored to be plotting their fate.

We’re a relaxed bunch, well-fed, tired of stormy weather, happy for the present good weather, and working together to get the job done.

All is well on the Nathaniel B. Palmer.

Jim Swift
Chief Scientist
NBP-1102 / S04P

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S4P: 31 MAR 2011 (REPORT) Oct 2, 2013

Our decision to do a somewhat-shortened version of the 170°W section worked out fine. (We’ll attach a map to show you where we have sampled to date.) The weather was great, we completed the 8th (final) station 6 hours before deadline, and the data showed the features we hoped to measure. We then began a planned 50-hour steam to our next station. Half-way through we had to slow down due to the rough ride in moderately heavy weather. The slow-down used all the hours we had gained and then some, but we finally got back to work.

At our last station on the 170°W line a group of humpback whales swam around us - close by - for a couple of hours (See below). Although we have no way to know, they seemed to be enjoying themselves, swimming by in different positions, flapping fins on the water, making grunting sounds, etc. Just listening to their deep breathing was a treat.

As discussed in past reports, east of 150°W we widened our station spacing from the originally planned 30 nautical miles to 45. We plan to keep to this spacing until approximately 130°W.

If weather were ideal, we would deploy the Yuan/Sprintall mooring at 66.6°S, 136°W tomorrow afternoon, but that seems unlikely. There is list of planned events - bathymetric survey, on-site and regional CTD casts, the mooring deployment itself, XBT deployments along the path we steam - some of which can be in any order and some of which must occur in sequence. The team is very well prepared; all we need is good enough weather, which at present is in short supply. Watch for next week’s report to see how it all came out.

Well presented general information about our cruise is updated frequently on Juan Botella’s blog. Juan is a high school science teacher from Wisconsin who is participating on our cruise as part of the NSF-sponsored PolarTREC program. You will see that Juan is gifted at describing what we do and he is also an excellent photographer. Please see <http://www.polartrec.com/expeditions/seawater-property-changes-in-the- southern-ocean>.

Life on board has been fine. We eat well (or a little too well in some cases). There are a few group activities such as a themed movie time. We were recently “killed” one by one in the stealthy tag game “murder” which is popular on research ships. (Juan was the winner, meaning the final “murderer” and last “alive”.) The cribbage tournament is into round two. And there are plans afoot for a couple of other group events or activities. Little things, but it keeps life moving along.

All is well on the Nathaniel B. Palmer.

Jim and Alex

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S4P: 30 MAR 2011 (LETTER) Oct 2, 2013

Dear Family, Friends, and Colleagues,

Our decision to do a somewhat-shortened version of the 170°W section worked out fine. (I’ll attach a map to show you where we have sampled so far.) The weather was great, we got the 8th (final) station done 6 hours before deadline, and the data showed the features we hoped to measure. We then began a planned 50-hour steam to our next station. Half-way through we had to slow down due to the rough ride in moderately heavy weather. The slow-down used all the hours we had gained and then some, but we are back to work in light winds, easier seas, and fog.

At our last station on the 170°W line a group of humpback whales swam around us - close by - for a couple of hours. Although we have no way to know, they seemed to be enjoying themselves, swimming by in different positions, flapping fins on the water, making grunting sounds, etc. Just listening to their deep breathing was a treat.

Some of you have asked for more about life on board. Juan Botella’s blog covers some of this. Juan is a high school science teacher from Wisconsin who is participating on our cruise as part of the NSF-sponsored PolarTREC program. You will see that Juan is gifted at describing what we do and he is also an excellent photographer. Please see <http://www.polartrec.com/expeditions/seawater-property-changes-in-the- southern-ocean>.

The Palmer is 303 feet long and 60 feet wide. We work and eat on the main deck level, which includes the outside working decks, the “Baltic room” from which we deploy most of our instruments, 6 principal laboratories, marine tech shops, the galley, the mess room, and some of the food storage areas. The staterooms for most of the science and Raytheon team are on the “01”, i.e. one deck above. The machinery spaces, shops, storage, and tanks are below the main deck, and most of that territory is off-limits for good reason. Although there are other, successively smaller decks above - the bridge (“05”) being the top

  • each of us spends most of each day in a relatively small portion of the ship. Most of us work 12-hour shifts. That’s a long time “on”, but the work is usually not too intense and we like having 12 hours “off”. Meals are served cafeteria style at 0730-0830, 1130-1230, 1730-1830, and 2330-0030, plus there is always food available at other times such as coffee, tea, soda, milk, juices, fruit, cereal, bread, sandwich fixings, crackers, and a host of fresh- baked goodies - and more. There is fresh-baked bread almost every day, and, this being a Louisiana ship, there are beans and rice available at every meal. Breakfast is pretty much your traditional breakfast choices. At lunch and dinner (each has a different menu) there are typically 2-3 entrée choices, one or two starches, a soup (the same for both meals), and one or two vegetables. At mid-rats (what the 2330-0030 meal is traditionally called) there are breakfast items, some leftovers from earlier meals, and often a special item or two, such as fresh bagels, or pizza, or, well, almost anything. Meal time is a social time, and enjoyed by all. In our time off we do our laundry (there is a self-serve laundry on each level where there are berths), use the gym, enjoy time on the bridge, read, watch movies, play cards, practice a musical instrument, etc. - and sleep of course. Most people have roommates and the work schedule and roommate assignments were coordinated where feasible so that people on opposite shifts room together. Every day is pretty much like every other day except for weather and food. We have talks - science or slide shows of trips - on Wednesday evenings and Saturday after lunch. These are open to everyone. We spend no time on the internet because we have no internet here, but everyone looks forward to email. There is a conference room on the “03” level and a movie theater (like a large home theater) with comfy recliner chairs on the “02” level. There are DVDs you can borrow to play on your computer, too. Each stateroom has its own head (bathroom) with sink, toilet, and shower. We are responsible for all our own cleaning. The crew does an amazing job keeping the public areas of the ship clean - this is one of the cleanest, best maintained research ships in the world - and we try to help out by keeping our cabins, and especially the labs, in good order. The crew is always very friendly and helpful. It’s a relaxed, pleasant environment, though in work terms never a sloppy one due to our universal attention to safety and to maintaining very high measurement and procedure standards.

There are a few group activities such as a themed movie time. Presently we are being “killed” one by one: a tag game called “murder”, popular on research ships, is in final stages. You are “killed” by the murderer accosting you in private with the Queen of Spades. If you correctly challenge the secret “murderer” before you are a victim, you become the new “murderer”, but if you are wrong, you are “dead”. Meanwhile the cribbage tournament is into round two. And there are plans afoot for a couple of other group events or activities. Little things, but it keeps life moving along.

All is well on the Nathaniel B. Palmer.

Jim Swift
Chief ScientistL
NBP-1102 / S04P

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S4P: 25 MAR 2011 (REPORT) Oct 2, 2013

We had a different sort of week than just one CTD station after another. First we enjoyed a transit through all sorts of ice, dodging zones where heavy ice would significantly slow us down, with a gorgeous sunset and moonrise. Then it was time to recover two arrays of bottom-anchored instruments Alex deployed during February 2010.

When we reached the first mooring site, Alex and Woods Hole mooring expert Jim Ryder (we are most fortunate to have him on board with us for our mooring work) went right to work. The Captain brought the Palmer near the expected location as they tried to communicate with the mooring’s release devices. Alex and Jim received only a weak, partial answer so began a search pattern, learning that the releases were more than a mile away from where they had been set down - perhaps an iceberg dragged the mooring sometime during the year. It was then too dark to try to recover the mooring, so we did a short line of CTD stations overnight. In the morning the weather was too iffy for a mooring recovery, so we headed over to the second mooring, about 32 miles away, to try to verify its location. By then the weather was seriously deteriorating and so we were able to do no more than learn that it, too, had been dragged, more than two miles. Further work was impossible and so we headed into the ice pack to wait out an impressively ugly storm. With blocks of ice being tossed about the sea surface in 60-knot winds, thank goodness we were safe on a sturdy icebreaker! When conditions improved, we headed to the first mooring site (the closest), where Jim and his team from the ship (our marine techs and the graduate students) recovered the mooring with few problems. Then we returned to the second mooring site, and in growing darkness its releases were acoustically triggered, and, voila, there was its blinking light beacon! The recovery was trouble free and Alex got back every instrument he deployed.

Readers who are oceanographers may be interested to note that during our lines of CTD stations at each mooring site we saw water at several hundred meters depth that was colder than the freezing point at the sea surface. This can take place when cold water circulates and is cooled under floating, very deep reaching Antarctic ice shelves.

We then had a long steam to the start of our next line of CTD stations during which the students and a couple of other helpers dropped XBTs every 30 minutes over the day and a half transit.

Cruise plan adjustments were at the top of our agenda this week. We get great advice from scientists ashore, but in the end it is our responsibility to manage the cruise. We started with a good plan and are keeping with it to every degree feasible. On the plus side, the station work is going great and we are spending less time in the ice than we thought we might when we planned the cruise. On the minus side we have lost more than 7 days to bad weather. The cruise to date included work of such high scientific priority that we felt compelled to complete it as planned, without reduction, and waiting out bad weather. But now as we begin the second half of this long cruise, we have decided to allot specific amounts of time to each remaining segment of the cruise except for a few “must complete, no matter what” activities. This is one way to get around the unknowns. The Captain is happy to work in a somewhat similar manner: within proper maritime limits he can allocate fuel in a cruise-segment manner roughly similar to our allocation of time. (As nearly all of you know, the ship uses far more fuel breaking ice than traversing open water, and also burns significantly more going, say 11 knots than 9 knots in open water.) Both of us plan when and where we will apply our resources and where we will hold reserves.

We have thus determined that we will have a go at the south-to-north line of stations along 170°W we had been prepared to cut just days ago. We allocated sufficient time to do 8 stations with average 43-mile spacing (but positioned to hit the deeper channels), and we will complete as much of it as the weather permits. Our section across the Ross Sea slope just NW of the major shelf channels has captured cold, fresh, high-oxygen bottom waters of shelf origin on the slope. The coming stations will track this water into the deep interior of the Ross Sea. Then we will move on to the next segment.

We are fortunate to be able to work with this superb team of technical specialists, with our enthusiastic students, with the expert captain, mariners, engineers, and support staff Edison Chouest Offshore provides on the Nathaniel B. Palmer, and with our experienced group from Raytheon Polar Services.

All is well on the Nathaniel B. Palmer.

Jim and Alex

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S4P: 24 MAR 2011 (LETTER) Oct 2, 2013

Readers of the letter seem to especially enjoy the photos. Here are some additional photos:

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