Clear water, grey skies, and colour on deck

by Penny Holliday

The good news last night – as we steamed towards our westernmost point of the section, just off Cape Farewell, Greenland – was that the water was clear of ice and we could get as close to shore as we had planned to go. The bad news was that it was 3am and very dark outside! This seemed to limit our sightseeing opportunities at this spectacular piece of coastline, but happily those of us who stayed up were rewarded with a lovely view of Greenland and some icebergs as the morning light appeared. Needless to say my photograph doesn’t do it justice!

As day was breaking we headed back out into deeper water to find the first of the OSNAP moorings that we plan to recover during this cruise. The conditions were clear and calm and not too cold, though the sky was grey and flat. However the day was brightened by the colours on deck: yellow, red, and orange of the mooring buoyancy spheres and people in their warm high vis coats and hard hats.

The photos show the sequence of a mooring recovery operation – an acoustic signal is sent to a device at the base of the mooring, telling it to release the large weight at the seafloor, allowing the whole string of instruments to float to the surface. The ship is positioned along side the mooring, which is now streamed out along the surface of the water, and the top of the wire hooked with a grapple. Cranes and deck winches slowly reel the wire in, while each instrument is removed as they come in, and taken into a lab for the data to be downloaded.

We successfully recovered two moorings today, giving us a whole year of precious measurements of the deep North Atlantic currents – tomorrow we lay a new set of instruments in their place.

Photos by Penny Holliday

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Before the game starts

by Feili Li

It has been two days since we left Reykjavik and we are heading southwestward to the Irminger Sea, east of Greenland. It will take about another day before we reach the location of the first CTD station near the Greenland side. So before we get there, let me explain several things: who we are, why we are in the cold subpolar area, and what we are doing before getting to the working site.

We are a group of enthusiastic hard-working researchers coming from seven institutions and four countries on a research cruise aboard RRS Discovery. Here the word “researcher” is preferable to “scientist” because we have an artist Mia and a photographer Amanda onboard – we are all doing research, just in diverse disciplines. (If you are as interested in their work on the cruise as I am, stay tuned to our blog!) Below are some nice photos of us.

One of the main goals of this research cruise is to retrieve data (sea water temperature, salinity, and current velocity) from the moored array as part of OSNAP, which has been sitting in the Irminger basin for another full year. After the data retrieval, moorings will be redeployed and will be staying in the water for the next two years. Processing of the data will begin shortly after they have been collected, although it may take several months to finish the processing and quality control of all these data. With the data, we are one step further towards the first result about the overturning circulation in the subpolar North Atlantic. It will provide unprecedented opportunities for understanding how water masses formed at high latitudes are tied to large scale Atlantic circulation that relates to climate change and variability.

Before getting to the site, we are generally free. I feel like I have moved my office from Durham in North Carolina to the ship. Except for training on CTD watch, I have been basically working on my laptop in a lab with a nice ocean view. The boundary between work and life disappears: eat, tea, work, eat, tea, work, eat, eat, eat … Yes, the boundary between the times you are eating and the times you are not eating also disappears. But, soon, this will be substituted with days filled with lifting, walking, taking water samples, and that is when the real game starts.

Photos by Neill Mackay

Photos DY054.pdf

The next stage of the OSNAP 2016 fieldwork

by Penny Holliday

RRS Discovery cruise today left Reykjavik on what surely must be the most beautiful day of the year so far. Sailing into glaring sunshine over blue sparkly water brings a optimistic lift to the heart of this Principal Scientist – it almost makes you think that we won’t need all of those extra days we have scheduled in case of delays due to bad weather… But the bad weather will probably come at some point, so I wont yet get too carried away with talking about calm conditions.

Most of us have spent a few days in Reykjavik, getting excited by seeing four research vessels in port at the same time (surely quite unusual?), gasping at the price of shopping, and admiring this stylish city in all it’s crazy-weather glory. But now we are glad to be getting going and getting on with the task ahead of us.

This cruise DY054 is the second UK OSNAP mooring refurbishment cruise of 2016. We’ll be retrieving some moorings and instruments that have been collecting deep ocean data for the past year, and sending a new lot of instruments back to replace them. We’ll also be releasing some ocean-exploring robots – floats that will spend two years following the coldest and deepest water so we can trace the many ribbons of currents that make up the southward-flowing circulation.

Photos by Penny Holliday

OSNAP, Year 3 Leg 1, 56 42.45N 33 42.02W, 19-July-2016, At the Bight, and Oceanographer Heartbreak

by Heather Furey

So, we made it! We are at the Bight. I have to say though, troops are restless. There are rumors flying around the ship about when we’ll get back. I have heard, ‘Not til Saturday 0600’, ‘Definitely Friday 2200, before the bars close’, and ‘Friday morning 0900’, as time estimates. All ETAs reported just today, and all from reputable sources! We are in the UNOLS ship schedule to hit the dock Saturday July 23rd, so anything earlier is, well, earlier. Really, it just depends how fast we can get this set of nine CTD stations done. There is a lot of motivation to get back Friday night. We are in the middle of the third CTD cast as I write.

I saw the first sun I have seen in a long time this morning as we travelled south, though it is cold outside today. The ocean looks pretty much the same here as anywhere else, but underneath us is a totally different story. We are over the south channel of the Bight now, a deep channel running east to west through the Reykjanes Ridge. Here and the north channel of this fracture zone are the only deep passages from east to west through this mountain range for hundreds of kilometers to the south, and the very first passage through since the deep overflow current first formed and started flowing southward at the head of the Iceland Basin.

From the perspective of being at the south channel’s deepest point, the mountains rise 1200 meters to the south and at least 1400 meters to the north. We have not passed over the highest point yet, so I have no multi-beam bathymetry data to know how shallow the northern mountain stands. If I were out hiking, I would expect some strong mountain pass winds through such a gap due to orographic steering. We think we might expect this here too in an oceanographic sense, water flowing strongly from east to west, funneled through this narrow gap. A velocity profile will be available soon, once ‘the package’ is on deck. (‘The package’ is the suite of water sample bottles, LADCP, which measures velocity, and CTD, which measures pressure, temperature and salinity.)

There are a couple of moorings out here now, one in each channel, that get pulled out summer of 2017, next year. Can’t wait to see what those data show, but they are so much more valuable for the velocity, temperature, and salinity data were collecting right now. We are taking a reference section, from which we can get transport, and to which we may compare the two years of mooring velocity, temperature and salinity data later.

Back in the lab, though, folks are packing up. Clean work tables? Packed bags four days before we hit port? Definitely, folks are ready to go home. And getting creative with how they spend their spare time (see map of Scotland). Food is still very good; I am impressed. Swordfish with fresh chili pepper and red onion salsa, julienned carrots, with cabbage, and also squash? I love vegetables, and the fact that there still exist freshly prepared vegetables weeks after leaving port is like gold to me. Thank you, Mark and Wally.

Update: Oceanographic Heartbreaker. The cooling on the hydraulic part of the deep tow winch failed at 0330 this morning (20 July), and we were not able to complete the section across the Bight. It would have taken about six hours to fix, and we did not have enough time left. We have some very valuable data in the form of a complete section across the southern channel, but it is a real disappointment! Stuart, our Chief Scientist, states that in his experience things tend to fail at the end of a long trip, especially when trying to do a bit extra work. Well, this is a case in point.   So we are headed back to the dock, ETA now about 1400 on Friday. Cruise complete.

OSNAP Year 3 Leg 1, 17-July-2016, 58d 45.19N 30d 16.38W, Back on The Line

by Heather Furey

We are nearing the end of this cruise. We have four more CTD stations to take on the OSNAP line, one ‘cal-dip’ (where instruments are attach to the CTD frame and calibrated in deep water), one mooring to deploy, having recovered its companion mooring in pea-soup fog this afternoon, and one final mooring to turn-around (both recover and deploy). My head is on land today, laying out plans for hiking in Iceland when I get there, and for getting home to see my peeps. I think it is because we went so close to Reykjavik when Greg got picked up by helicopter.

But, we are still at sea.

pokemon

Here on board, a few things: First, Wally’s Surprise was served at dinner tonight. I can’t tell you what it was, because that would spoil the surprise for the next Leg’s science crew, but it was pretty darned good. Excellent, in fact. Second, some mystery person has been putting up Pokémon monsters hidden in plain sight around the ship. Pokémon Go, here. I do not have much to say about that, just that it is happening.

wallys_surprise

Now that we are nearing the end of the scheduled science, we get a little time to play! Most cruises have a few ‘weather days’ built in to the schedule, for things like gales, or getting personnel helicoptered off the ship, or equipment repair … whatever comes up. See how the ship is sort of near the Bight Fracture Zone? We seem to still have a breath of time left, and will use it to go back to the Bight!

Part of measuring the overturning circulation (O-SNAP=Overturning Circulation of the Subpolar North Atlantic Program) is measuring the bottom currents. The Iceland-Scotland Overflow Water makes up the bottom current that flow southward from the shallow sill between Iceland and Scotland. The dense overflow water sinks to the deep Iceland Basin and forms a boundary current travelling from north to south along the west side of the Iceland Basin, which is also the east flank of the Reykjanes Ridge. But, this “flavor” water is also found in the western Atlantic Basin and it is still not quite known exactly how this water gets from one basin to the other.

fracturezone

This is where the fracture zones come in. Fracture zones are deep breaks in the ridge, like missing vertebrae in the spine of the North Atlantic. Historically, if you open a research paper that is puzzling out this mystery, you would see a figure showing the deep ISOW water arrow following the eastern flank of the Reykjanes Ridge, turning into the western Atlantic through the Charlie Gibbs Fracture Zone further south. This is the deepest and widest fracture zone in the Reykjanes-Mid-Atlantic Ridge system.   But these days, we think that some of (all of?) the shallower portion of the deep ISOW current flows through upstream cracks in the Reykjanes Ridge into the western Atlantic. Makes sense to me. How much? Modelers have estimates, but no one has measured it.

The Bight is a shallower fracture zone upstream in an Iceland-Scotland-Overflow-Water sense. We went there first in 2014, on the first OSNAP cruise, knowing that that no-one had ever taken CTD stations in this fracture zone. Second time in all of history the Bight will be surveyed? Sign me up, let’s go!

P.S. Greg is on a plane home to Miami as I write, back to family and good care. Safe and sound.

OSNAP Year 3 Leg 1, 15-July-2016, 61d 07.77N 28d 47.43W, steaming north

by Heather Furey

We woke up this morning to the awful news of a van driving into a crowd celebrating Bastille Day in Nice. Our French nationals onboard did not personally know anyone hurt. So sad and so useless, the killing.

You might notice by the latitude and longitude above that we are no longer on the OSNAP line. Two reasons: Firstly, at about 15:00 yesterday, we started to steam north to avoid the worst of an incoming gale. We would have been down for weather anyway, so it was wise to outrun the worst of it. Secondly, we are steaming to Reykjavik to rendezvous with an Icelandic Coast Guard helicopter.

This came about because a member of the science party injured his back a few days ago: an old back injury that was seriously aggravated during an odd twist during the deck work of mooring recovery. Early this morning, since there have been no signs of improvement, the captain decided that Greg needed better and more immediate medical attention. The captain consulted with the UK Coast Guard to see what the best course of action should be. The UK Coast Guard contacted the Icelandic Coast Guard, and we are now en route to rendezvous 150 nautical miles from Reykjavik, the outer range for the rescue helicopter, where Greg will be ‘helivac’ed back to Reykjavik, a doctor, medical treatment, and home.   We are sad he is leaving us, but glad that he will be in less pain soon. Eight more days under rolling seas with limited sleep would have been very unkind.

helivac

One thing about being at sea, everyone has a story.

Yesterday, I deployed the last of the RAFOS floats. The captain had come to me earlier in the day with the idea that while we did not have time to complete CTD stations while outrunning the storm, we did have time to complete the RAFOS deployments. The deployments are quick: before coming onto station, the float, which has been previously tested and armed for mission, is loaded into a launching tube. A starch ring, which will dissolve in water, is inserted into a piston release mechanism. The bottom trap door on the launch tube is wired to the piston. As we come onto station, the ship slows to about two knots speed. The loaded launch tube is lowered into the water, the starch ring dissolves, the trap door at the bottom of the launch tube opens, and the glass float slips into the sea as we slowly steam away. Although it takes some time to set up for deployment, the actual deployment takes just a few minutes.

rafos

It is my great pleasure to be allowed into ‘The Red Zone’, at the aft guard rails, to help with and oversee the deployment. The ship’s crew helps me, and I am grateful for their necessary and able assistance.  While deploying the last of the RAFOS floats at the back rail, I had time to talk with the A/B, Will, who was helping me. He came to this job after spending years in the UK Army as an explosive specialist. He told me tales of crawling through the wire and pipe tunnels under the city streets in Northern Ireland finding and disarming bombs planted by the IRA. And of being in Afghanistan searching for land mines by poking a metal pole into the sand, describing the sound of the metal on metal clunk when he would find a mine. He would then dig the live mine out of the sand, and disable it to ensure his own troops’ safe passage. An explosives specialist, standing next to me, helping me launch armed-for-mission RAFOS floats into the abyss. You just never know.

redzone

Another piece of a puzzle

By Tiago Bilo

After the 15th day at sea, scientists from University of Miami lead by Dr. William Johns had successfully deployed their fifth deep water mooring under the curious watch of Pilot Whales. This mooring is part of the set of nine moorings placed on the North Atlantic subpolar gyre, close to the fractures and rough topography of the Reykjanes Ridge (off the southern coast of Iceland).

As the RRS Discovery moves forward in completing its mission, we gather more and more important data that will help us to put the pieces of the circulation puzzle together. The size of the piece will depend on the puzzle of interest. Each equipment recover and deployment may represent a large piece to understand the circulation within a channel or fracture, or a tiny little piece of the Earth’s climate system.

 

miami_mooring

University of Miami group (Greg, Tiago, Mark, Cobi) and John (RRS Discovery CPOS) deploying one of the moorings.

 pilot_whales

Pilot Whales carefully watching the RRS Discovery ands the research activities

 glider_SAMS 

Deployment of one of the Heather’s (Woods Hole Oceanographic Institution, US) glider being watched by crew members and Scientists). Using yellow hard hats are SAMS scientists Loic (on the left) and Stuart (on the right).