Another day at the office: data quality control

by Roos Bol

Now that temperatures outside are dropping and storms are raging over the subpolar gyre, it is clear that the OSNAP field season had ended. Many blogposts have been written about the exciting adventures at sea last summer. This time however, I would like to tell you a bit about the – slightly more boring – work that happens after. When the exhausted but ultimately satisfied scientist returns home, with a hard drive full of newly recovered data; that’s when our real work begins. Before the new data can be used to answer actual science questions, they are in dire need of some cleaning.

Why is that necessary? Instruments on a mooring (a cable anchored to the sea floor) are impacted by currents, storms, tides and sometimes fishing activities. There is the risk of colonization by omnipresent sea creatures. In the vast open space of the ocean, an instrument can provide a welcome place for shelter. Instruments deployed in the sunlit surface layer are all overgrown with algae upon recovery. But deeper instruments can also host interesting inhabitants, such as the anemone in the picture below. Last but not least, the ocean is salty, wet and under high pressure. A challenging environment for an electronic instrument, especially with our long deployment period of two years! 

Figure 1: Some examples of sea life on the moorings upon recovery: a slimy creature on a Microcat, an anemone growing on a ring of the release that was at almost 2000m depth, and a shallow UK buoy overgrown with algae.

Data quality sometimes suffers from all these environmental impacts. This is where my work of the past few weeks comes in: checking, cleaning and processing the raw data records. Below are examples of Microcats on one of our moorings, called IC2, during the last deployment. Unlucky for us, the anchor of this mooring ended up shallower than planned, on top of a small seamount. A storm resulted in the exposed top buoys breaking down, making the shallow instruments sink to the deep. The top Microcat, originally at 25m, was instead dangling loose at around 700m depth… it is a small miracle it was still attached to the cable when the mooring was recovered! 

(For those who are wandering; yes, luckily there was another buoy at 350m, keeping the deeper part of the cable standing up straight!)

Severe storms impact the mooring even deep down in the water column. The pressure record of the Microcat at 352m depth (figure 2) still shows many big and small ‘blowdown’ events. During such an event, strong currents push against the mooring cable, blowing it down at an angle and pushing the instruments deeper into the water. When the storm ceases, the buoys on the cable pull the mooring cable back to its original straight position.

Figure 2: Pressure time series of the Microcat at 352m in mooring IC2 for the last deployment (August 2016 to July 2018)

Microcats also measure temperature and salinity. Figure 3 shows the raw salinity record from the deepest Microcat on IC2, close to the bottom at almost 1900m depth. As you can see, salinity differences in the deep ocean are generally very small. However, salinity measurements are notoriously noisy, so we need to perform some filtering of data spikes. But which spikes are bad data, and which represent real variability? Then there is a suspicious drop at the start of the record; perhaps a small animal or algae was temporarily covering the sensor?

Figure 3: Raw salinity record from the deepest Microcat in IC2, at 1892m

Lastly, and perhaps most importantly, we need to perform a calibration for all sensors. From the ship, we dip the instrument into the ocean and test its readings against a calibrated reference sensor to determine any offsets, both before and after the deployment. This is the only way to check whether an instrument gives accurate readings.

Overall, it is probably clear that there is a lot of effort involved in scrutinizing the records and ensuring data quality control is performed correctly. But although it may sound a bit tedious, the quality control step is extremely important. It ensures that we have accurate, reliable records, on which we can build for further analysis – to eventually formulate valid answers to scientific questions!

Aboard the R/V Atlantic Explorer east of Abaco, the Bahamas

by Bill Johns

At sea again!

No, not an OSNAP cruise this time, but in the balmy subtropics at 26°N.

I am leading a group from the University of Miami and NOAA’s Atlantic Oceanographic and Meteorological Laboratory (AOML) on this 18 day cruise, where we will recover and replace several deep moorings and collect hydrographic profiles near the ocean’s western boundary off the Bahamas as part of the RAPID/MOCHA program (http://www.rapid.ac.uk/rapidmoc/). One of our key goals is to monitor the strength of the Deep Western Boundary Current (DWBC) that carries deep waters formed in the subpolar region southward toward the equator, in the lower branch of the Atlantic Merdional Overturning Circulation.

Unlike our OSNAP cruises, we are wearing t-shirts on deck and scanning for the elusive “green flash” on clear days at sunset – a somewhat more comfortable existence to be sure, but as on all cruises the work is nonstop. We’ve experienced a short November gale on this cruise that shut down our sampling for awhile, but we are mindful of the fact that we’d much rather be here now than up in the high North Atlantic!

The last CTD recovery before shutting down our overboarding operations.

Even though the subpolar gyre seems far, far away, the data we are collecting on this cruise is a constant reminder of the connection between what is happening here in the subtropics and in the subpolar region. We can see clear evidence in the DWBC water mass properties of changes in the intensity of deep water mass formation in the North Atlantic over the past few decades. Although the RAPID program only started in 2004, the AOML group has been making measurements of the water mass composition of the DWBC here since the mid-80’s as part of their Western Boundary Time Series (WBTS) program. The biggest change occurred in 1995 when a new pulse of much colder and fresher (less salty) water originating from the Labrador Sea arrived at 26°N. This pulse followed a period of very strong cooling in the Labrador Sea starting about 9 years earlier that resulted in the deepest and densest formation of Labrador Sea Water in more than 60 years. The 9-year transit time for that pulse to arrive off the Bahamas means it couldn’t have all come in a fast-track pathway within the DWBC itself, but very likely followed one or more pathways through the ocean interior, for which there is other independent evidence. The peak of that event occurred in about 2003 off the

Bahamas, again just about 9 years after the peak of deep convection in the Labrador Sea in 1994. Since that time the waters in the DWBC off Abaco have gradually warmed, while deep convection in the Labrador Sea has generally decreased.

All that changed in 2014 with the onset of very strong cooling again across the subpolar gyre and extensive deep convection in the Labrador Sea – coincidentally (but auspiciously) timed with the start of OSNAP. If this turns out to be a sustained multi-year event, which it seems to have the makings of, then the next several years will be very interesting. Will this be a playback of the mid-90’s event, or will something different happen? We know the ocean is taking up a great deal of the excess carbon dioxide we are putting into the atmosphere, and that the deep water mass formation in the North Atlantic is a key element of that uptake. What we know much less about are the pathways and processes by which carbon is transported and stored in the ocean and he time scales of those deep ocean transport processes. Obviously we’ll have to wait a while to find out what happens, but the difference this time around is that we will have the OSNAP, RAPID, and other deployed AMOC arrays, as well as the fully-deployed Argo array, to help us out. THAT is progress.

IPCC special report 1.5C warming

by Ric Williams

On 8 October a special report was released from the Intergovernmental Panel for Climate Change to highlight the impacts of global warming of 1.5oC above pre-industrial levels. The report is substantive and is led by 91 authors drawing upon inputs of over 2000 experts, nearly 500 reviewers and citing 6000 papers. The report is set in the context of the Paris Climate agreement in 2016, which aspires to keep global temperature rise to less than 2oC this century and to pursue efforts to limit the temperature rise even further to 1.5oC. What has been unclear is how long have we got until we reach this warmer climate and what are the likely consequences?

 The headline is alarming, the clock is ticking faster than we would like. There are a dozen years to keep below a global temperature rise of 1.5oC. We are on track to exceed this threshold by year 2030 given the present rate of carbon emissions. The message is simple: the more carbon we emit, the warmer the climate system becomes.  We need to reduce the amount of carbon we are emitting to the atmosphere.°°

The report assesses how a 1.5oC warmer world compares with a 2oC warmer world. Drawing upon climate model projections, there are robust differences in regional climate between a 1.5oC and 2oC warmer world: the mean temperature and extreme temperatures are higher for a 2oC world (high confidence) and there is heavier precipitation in some regions and drought in some other regions (medium confidence), and that there is an extra 10cm of sea level rise, affecting 10 million more people. The effects on the habitat are viewed as alarming with twice as much habitat loss for plants and insects for 2oC warming compared with 1.5oC warming. Warm-water corals are effectively wiped out with a 99% loss for 2oC warming, while 10% might survive with 1.5oC warming. Arctic sea-ice free summers are viewed as being once every 10 years with 2oC warming, rather than once every 100 years with 1.5oC warming.

There are real benefits to acting sooner to limit the increased warming of the climate system. What is needed is to reduce the amount of carbon emissions and the resulting amount of carbon dioxide in the atmosphere. Proposed solutions include reforestation, a shift to electric transport systems and development of carbon capture. The challenge is severe, we need to reduce global carbon emissions by 45% from year 2010 to 2030. We can only achieve this goal by keeping as much carbon as possible in the ground and not releasing further fossil fuels. Meeting this challenge will be demanding.  

Postdoctoral Research Associate positions – The Scottish Association for Marine Science

PDRA positions in Physical Oceanography Oban, Scotland

Fixed term appointment for 3 years

£27,285-£30,688per annum

The pre-eminent scientific challenge of the 21st Century is to understand the drivers of Earth’s climate. The North Atlantic subpolar ocean is closely coupled to Arctic, European and tropical regions through the atmosphere, and is strongly linked to decadal climate variability. At SAMS we are researching the physical processes of ocean-atmosphere interaction and circulation.

Position 1

SAMS has a leading role in developing sustained observing programmes in the subpolar Atlantic for example through joint leadership of the International Overturning in the Subpolar North Atlantic Programme(http://www.ukosnap.org/ & http://www.o-snap.org/).OSNAP is a world leading subpolar transatlanticmooring arraypurposefully designed to elucidate links between Atlantic circulation and climate. You will be responsible for taking a leading role in analyzing observations from the NERC funded OSNAP programme.

We seek a Post Doctoral Research Associateto manage and develop SAMS expertise in basin scale ocean observations for climate and to become a future leader in the field. The main duties are:

  1. Contribute tothe preparation, planning and execution of CLASS research cruises and glider programme.
  2. Contribute to the deliveryof objectives in EU programmes.
  3. Lead and publish high quality peer-reviewed research.
  4. Form and maintain national and international relationships and collaborations.
  5. Travel to national and international meetings to present research findings.

Position 2

SAMS has a leading role in developing sustained observing programmes in the subpolar Atlantic for example through joint leadership of the recently funded £25M UK NERC Climate Linked Atlantic Sector Science Programme. This position will contribute to making new observations (moorings and gliders) and research on the topic of Ocean Salinity and the Hydrological Cycle. You will also contribute to two EU H2020 programmes Blue Action (focused on lower latitude drivers of Arctic weather and climate) and ATLAS (understanding physical controls on Atlantic cold water coral ecosystems).

We seek a Post Doctoral Research Associate to manage and develop SAMS expertise in basin scale ocean observations for climate and to become a future leader in the field.

The main duties of the position are:

  1. Contribute to the planning and execution of glider based field programmes.
  2. Lead and publish high quality peer-reviewed research.
  3. Form and maintain national and international relationships and collaborations.
  4. Travel to national and international meetings to present research findings.

For general enquiries about the position please contact: Prof. Stuart Cunningham at Stuart.Cunningham@sams.ac.uk or Prof Mark Inall on Mark.Inall@sams.ac.uk

The closing date for receipt of applications is Friday 9th November 2018.

Learn more and apply

OSNAP! There goes the tip of the iceberg!

by Leah McRaven

Physical Oceanography
Woods Hole Oceanographic Institution

When you decide to study the currents that whip past the continent of Greenland and that transform the waters in the Irminger and Labrador Seas, an oceanographer must be willing to make peace with an ocean that isn’t entirely liquid. The extreme elements that shape the rocks along the Greenland coast also actively chisel away at the hundreds of glacial termini that meet the ocean edge. This chiseling leads to a constant flux of icebergs, small icebergs called bergy bits, and even smaller ice chunks called growlers. With ice in its various sizes and jagged shapes breaking away from the entire continent, the currents in the OSNAP region transport and mix more than just water.

Logistically, the OSNAP study region is one of the hardest places in the world ocean to successfully execute fieldwork. To start, the East Greenland Coastal Current, the East Greenland Current, and the Irminger Current can flow at speeds well over 1 knot as they round the tip of Greenland. In addition to strong currents, the area is home to a record: the windiest place in the world ocean. Simple ship maneuvering tasks, such as holding station while collecting data or recovering moorings (Figure 1), become challenging for the mates on the bridge as unforgiving winds build up rough seas that are already swiftly flowing. Floating ice is quite literally the icing on the OSNAP cake.

Ice adds a whole new dimension, and phase of matter, to navigation and operations at sea. From a distance, it can be nearly impossible to decipher ice chunks from whitecaps and sea spray. Large icebergs can be easy to see if they express above the surface of the ocean, but the majority of an iceberg’s mass lies below the sea surface and is difficult to see. Ice can also block access to nearby fjords used for shelter in severe weather. These navigation dangers keep the R/V Armstrong mates on high alert at all times as they steer through storms, darkness, and thick fog.

In order to help navigation efforts, WHOI researchers employed the help of the Danish Meteorological Institute (DMI), which specializes in satellite sea ice imagery. DMI is able to provide the ship with updates on the location of ice based on satellites that take Infrared (to see through clouds) and visible images of the Earth’s surface. Not only is this information extremely helpful, the maps can be stunning. Ice information from our current OSNAP cruise (on September 9th) is shown in Figure 2. This satellite image from the southern tip of Greenland is an example of how satellite-detectible ice features disperse from their mother fjords into the surrounding ocean.

Ice can also run into the OSNAP moorings, pushing instruments out of the way, or even snapping them off their lines making it impossible to recover them and their precious data. Our six shallow moorings on the continental shelf were, in fact, designed with drifting ice in mind. Equipped with a tripod-like structure at their base, these moorings have most of their instrumentation mounted near the sea floor. In an attempt to capture shallow data, the moorings also have special tethers extending up from the tripod base with weak links to top flotation. These weak links are designed to break easily should an iceberg snag the line, with the break point located strategically below the flotation and above an instrument. In the event of tether breakage, the instrument sinks to the bottom, but remains attached to the rest of the mooring so that it can still be recovered. Figure 3 shows a depiction of this breaking process. Of the recovered moorings from this year’s cruise, three of the six shallow moorings had their top floats ripped off within less than a year!

With all of the challenges handed to us from ocean elements, our crew has excelled in accepting the challenges brought on by ice. Of all 16 moorings that we aimed to recover on this cruise, all have successfully come back. In the face of extreme weather and rough seas, we have completed over 240 profile measurements of ocean temperature, salinity, and velocity thus far. And through all of these challenges, no one can deny how much they still enjoy seeing the Greenland coast in full panache with its towering and craggy icebergs.

Figure 1. An iceberg off the stern of R/V Armstrong during a tripod mooring recovery during the current OSNAP cruise.

Figure 2. Denoted infrared satellite imagery courtesy of the Danish Meteorological Institute. Pink triangle indicate the position of satellite-identified icebergs throughout the southern Greenland region.

 

Figure 3. Illustration of the OSNAP tripod moorings with weak links to top flotation. The left mooring demonstrates a normal deployment, while the right mooring shows a deployment with interference from an iceberg. In the event of an iceberg snagging the upper mooring tether, the top floats are released and the shallowest instrument falls, while still remaining connected to the mooring.

 

Last OSNAP cruise of the season on RV Neil Armstrong is underway – Blog 1

September 12, 2018 

by Isabela Alexander-Astiz Le Bras 

Two weeks ago we left Reykjavik on the R/V Neil Armstrong for the last OSNAP cruise of the season, a five week expedition to the outskirts of Greenland. Our goal: “turn around” two sets of OSNAP moorings and taking as many CTD casts as possible. In fact, Chief Scientist Bob Pickart is well known for taking particularly large numbers of tightly spaced CTDs. 

Every group will say this, but I think our region is the most interesting of the OSNAP array. East of Greenland, cold and fresh water from the north meet warm and salty waters that originate in the Gulf Stream. This place is a turning point for the ocean’s global overturning circulation, which helps stabilize the earth’s climate, yet measurements here are severely lacking, partly due to the conditions I will describe here. 

You may already know all this, but I’ll start by getting you up to speed on oceanographer-speak just in case. Moorings are long wires dotted with instruments that are anchored to the sea floor and take measurements for as long as several years. We are picking up our moorings after a two year deployment and are only able to access the data in the instruments once they are on board. We are also deploying a new set of moorings to leave in the ocean for another two years. The moorings we are servicing range from 100m on the shelf to almost 3km long offshore!  

The CTD (conductivity, temperature, depth) rosette is the workhorse of oceanography. This instrumentation package measures temperature, salinity and pressure/depth as it is lowered through the water column by a winch on the ship. It also includes Niskin bottles that are closed at various depths to collect water that is used for calibration and ADCPs (Acoustic Doppler Current Profilers) that measure ocean velocity. Our CTD package also includes a set of chipods, which Jonathan Nash from OSU very generously loaned me for this cruise. Chipods measure temperature gradients at high speed (100 measurements per second), providing a quantification of turbulent processes over centimeter scales. As our CTD sections survey ocean properties at finer spatial resolution than the moorings, we use these to learn about detailed ocean dynamics and to ground-truth the mooring measurements. 

Our first priority on this cruise is to retrieve and re-deploy the OSNAP moorings. However, this can only be done in daylight and when it is calm enough to be lifting large objects in and out of the ocean. A group of mooring specialists from WHOI and the Armstrong’s deck crew physically deploy and retrieve the moorings while others (like myself) take notes. To take full advantage of being out here, anytime that we can’t do moorings, we are doing CTDs. And by we, I mean a small army of graduate students, postdocs and technicians who take 8 hour shifts round-the-clock to operate the CTD. Of course, none of this work is possible without the ship’s crew who get us where we need to go and keep us safe on our floating home for these 5 weeks. 

I thought I knew what to expect, having been to sea several times before and having spent the better part of the last year analyzing mooring data from the first deployment. I was also fully aware that we were heading into stormy seas pretty late in the “calm season”. After all, we think the currents we are studying are driven by the winds that zip along the coast of Greenland and flare up at its ominously named southern tip: Cape Farewell. 

During the first few days that reality set in as we rocked and rolled our way to our study site. For me at least, there is a difference between knowing its a stormy region and being tossed around in my bunk for 24 hours. Our chairs slid across the main lab as we gathered to discuss plans and even the most seaworthy in the crew held on tight as they staggered down the hallway. It didn’t always feel great, but it sure helped me internalize that this really is one of the windiest places on earth. 

Once on the continental shelf of Greenland, we were greeted by stunning views and large craggy icebergs that were well worth the weather. During the first OSNAP deployment (2014-2016), the inshore-most mooring, CF1, was hit by such an iceberg and the instruments sitting at 50m and 100m fell to the seafloor about a year after deployment. While marveling at their beauty and size, I wondered how such iceberg casualties were not more common. Luckily, we managed to recover CF1 this time as well, though yet again the 50m instrument was knocked down to 80m less than a year into the deployment. 

For the rest of our stay east of Greenland we alternated between mooring recoveries and deployments, doing CTDs through the night, and hiding behind the cliffs of Greenland when the weather turned. Our mooring operations were successful with the exception of one mooring on the shelf that has refused to surface thus far. We will be back for it as soon as we are done with the rest of the moorings, but it stands as a painful reminder that what we are doing here is difficult, and that the ocean is full of uncertainty and surprises. 

Two days ago we crossed through the beautiful Prince Christian Sound to start all over again west of Greenland. Armed with successful mooring operations east of Greenland, two sections of CTDs and two weeks of experience working as a team, I think we are ready to take on the Labrador Sea! 

Recovering the flotation sphere for mooring CF4 with an iceberg in the background. Pictured from left to right: Andrew Davies, Pete Liarikos, John Kemp and Brian Hogue.Photo by Isabela Alexander-Astiz Le Bras 

 

The last step of mooring deployment is dropping this anchor off the fantail to the seafloor.Photo by Isabela Alexander-Astiz Le Bras  

 

View of a glacier flowing into the Prince Christian Sound. 

Final week from the RV Armstrong

by Femke de Jong

Today we steam for Iceland. After four weeks of mooring operations and CTDs even those among us who are always looking for more data are ready to go home. Part of it is mindset, we were prepared to work ourselves to the ground for four weeks to get this done and now it is done. Had we set out for six weeks I’m sure we would have continued tiredly, but motivated for another two weeks.

During these four weeks we recovered 19 moorings and deployed 19 new moorings in those same positions, plus one lander. The mooring teams of NOC, RSMAS and NIOZ worked together on each of these moorings. So while the PIs of the respective institutes had a break while another PI was overseeing his or her moorings, these guys worked continuously. From my workstation, which faced the CTD console with its many screen, I could nicely keep track of the progress on deck. While I was out there doing my own moorings it was good to have some more experienced people around who don’t panic when a mooring comes up in a tangle (oh, how I would have like to start recovering the line that held the instruments/data first…).

the screens of the CTD console. Keeping and eye on all the important stuff, position, ETA, CTD and deckwork.

Inside, we worked together to run the CTD watches. The day watch was allocated to the PI currently doing moorings/instruments. The night or zombie watch was divided between the others. Theoretically this requires “just” shifting your waking/sleep pattern by eight hours or so. In practice, you either completely loose contact with what’s going on during the cruise, because you show up just for dinner as the others are winding down from their day. I tried a different approach, being around more of the day. A short nap after my watch/breakfast, skipping lunch, and another nap between dinner and the start of my watch at midnight. While this allowed me to keep track of the ever changing plans, it did effectively turn me into a zombie for the time being. The cruise leader’s attempt to teach me the rules of cribbage directly went in one ear and out the other, without my mind having any chance to process the information. I wonder what else I might have missed…

But while we still had three watches, each covering eight hours of CTDs, the chemist team had to deal with 24 hour measurements with two people. So maybe it’s not too surprising I haven’t seen them much since they finished their work and were allowed to recover. I’m sure they’ll come out of their cabin once we get closer to Reykjavik.

At least we get to go home in a few days. Most of the Armstrong’s crew are staying on for another cruise. They have been very helpful and accommodating in our busy schedule and we’ve explained them the difference between the colored jerseys in the Tour de France. There was one unfortunately incident, where one crew went on a killing spree (playing the assassin game), but to be honest that whole thing was instigated by the some of the British participants.

All of us came together in our loathing of “weather” on this, somewhat lively, ship. An incoming wave attacked one of the folks attaching microcats to the CTD frame, they nearly lost one of the cats when were holding on (not quite) for dear life. A ladder of an upper bunk bed came off in the middle of the night and woke up the owners of the bed as well as those in neighboring cabins. After all, there is a reason why we spend our summers in the subpolar gyre… we would never have managed doing all of the above in winter. That time of year is much better spend analyzing all the data we collected, maybe next to a cozy fireplace.

Stuart, Roos and James discussing the latest plots of our section.

Across the North Atlantic Current

by Bill Johns 

Off we go again!

Its the 2018 OSNAP field season and we are aboard the R/V Neil Armstrong, the new pride and joy of Woods Hole Oceanographic’s fleet.   Pictured below is the R/V Armstrong coming into dock in the old harbor of Reykjavik, Iceland after completing two days of loading in the “new” harbor down the quay. This is my first time on the R/V Armstrong and I have been looking forward to sailing on her ever since she came out of the shipyard.

The R/V Neil Armstrong coming into dock in Reykjavik, Icleand.

The cruise has gotten off to a good start and we are now about halfway through our month-long voyage.  We have three science groups aboard, from the U.K. (the Scottish Association for Marine Sciences and the National Oceanography Centre, led by Dr. Stuart Cunningham), from Holland (the Royal Netherlands Institute for Sea Research, led by Dr. Femke de Jong), and from the U.S. (the Rosenstiel School of Marine and Atmospheric Science, University of Miami, led by myself).  We have a lot to accomplish on this cruise, and it still boggles my mind how many mooring operations we are planning to do on this one cruise. Altogether we have 21 moorings to recover and 19 to deploy, most of which are mooring “servicing” operations, meaning that we recover and redeploy a replacement mooring at the same site, usually on the same day.  The deck is full to the bulkheads with mooring gear, and many of the crew have commented that they have never seen the deck so full.  Thanks to the ingenuity of the deck crew and mooring teams we managed to find a place for everything (whereupon I can now admit that I was secretly worried whether we would actually fit everything onboard!).

The array of moorings to be serviced on the OSNAP East 2018 cruise.

In addition to the mooring operations, we plan to complete a full line of CTD stations across the entire array, amounting to some 80 stations in total. At these stations we will be measuring full depth profiles of currents, water properties (temperature, salinity, and dissolved oxygen), and also drawing water samples for chemical analysis including dissolved inorganic carbon, nutrients, and nitrogen and silica isotopes. 

Whew!

So far we have had very reasonable working weather, except for having to dodge the remnants of tropical storm Chris which came barreling through our array right where we happened to be working at the time.  So, we picked up and ran to the far western end of our line to resume work there, forcing us to develop a new “Plan B” that reorganized the entire layout of the cruise.

Such is life at the mercy of the sea.

I find it ironic that during the four OSNAP cruises I have been on since we started the program in 2014, the worst storms we have had to deal with have all come up from the tropics as post-tropical storm events.  So much for my plan of escaping from the summer storm season in Miami.

The last 5-day forecast for post-tropical cyclone Chris posted by the National Hurricane Center. The storm position on Saturday July 14th was right where we planned to be working at the time. Needless to say we decided not to stay around to see if the forecast track was correct.

One of the truly remarkable things about these OSNAP cruises – and in particular the part of the subpolar North Atlantic that we are crossing during this cruise – is that you can feel in your skin and bones just what effect the ocean circulation is having on the climate.  Part of our cruise takes place on the “warm” side of the subpolar gyre, where the North Atlantic Current brings warm waters originating from the Gulf Stream to Rockall Trough off the coast of Scotland and to the eastern side of the Iceland Basin.  This is the most looked forward to part of the cruise, where ocean temperatures are as high as 14 degC and surface air temperatures rise to match it.  A look out the back door to the deck often finds people who are off watch milling about aimlessly, squinting in the warm sunlight and enjoying the beauty of the sea. Then, eventually, whether we like it or not, its time to cross westward into the western Iceland Basin and Irminger Sea, where air and water temperatures are more like 6-8 degC.  And fog is almost everywhere. Suddenly you don’t see anyone on deck anymore unless they have to be.

The graph below shows the longitude along our track and the corresponding surface air and water temperatures. We started in the central Iceland Basin near 25 degE and first worked our way over to the coast of Scotland (~July 8th) and then headed back across the Iceland Basin and into the Irminger Sea where we are now.  Just remarkable how similar these three curves are.

We have an outstanding group of scientists on this trip, and I would like to highlight here especially the fantastic group of students who have joined us and are contributing greatly to our mission.  The pictures below show them hard at work on their various watch duties, seemingly enjoying the experience (or at least faking it really well).

 Below are some other assorted photos from the cruise showing the science labs and work taking place on deck.

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MSM 74 – Blog Entry 5

Over the past week we made great progress in our journey of the sea, surveying an eddy off the west coast of Greenland with repeated ADCP and CTD surveys to investigate in detail the structure and content of these dynamic water features. We also deployed 2 more APEX floats in the centre of the eddy.

Johannes and Marie discussing the next Apex float deployment (credit: Sunke Schmidtko).

Float deployment in the eddy centre (credit: Arne Bendinger)

During the last few days while we finished the Labrador Sea part of our cruise and had our mid cruise celebration, I had the chance to sort out my thoughts and go through notes of conversations with more of the people on board. One thing I realized is that I never mentioned the amazing crew and captain of the Maria S. Merian. Without their patience, experience and watchful eye neither the mooring work, nor our CTD stations would have gone as smoothly as they did.

Sandra Schilling, 2nd Officer on the Maria S. Merian (Photo by Arne Bendinger)

Besides doing a great job manoeuvring the vessel around always changing CTD station plans, the watch officers are always happy to have us come up to the bridge to say enjoy the sunset or answer questions about the many instruments on board. The watch officer during my CTD shift is 2nd officer Sandra Schilling and she has been on board the Merian for just under a year. I think it is amazing to see women in these leading roles and I am glad I got to meet Sandra on this cruise. I asked Sandra if she misses being on land, since 8 month of the year she spends at sea, but Sandra told me she feels happiest at sea and at the end of her time on land she always feels excited to be back on board for the next voyage. Apparently the coolest thing about her job is to navigate in unchartered waters. Pun intended!

As the current week is coming to an end near the Cape Farewell, Greenland I am also ready to describe more of the great group of people I share this cruise with. I like interdisciplinary nature of our cruise. One of the scientists from Canada, fresh from finishing her honors thesis is Ciara Willis. Ciara described to me a lifelong passion for marine biology that started at age 4 inspired by conservation issues in Nova Scotia. Ciara recently finished a degree in Marine Biology and Statistics in which she took part in projects in both Canada and the US and is now on this cruise sampling nutrients and vitamins from the CTD casts to investigate microbial activity in the sea as part of a research project at her University.

Picture of Ciara Willis doing sampling in the Chemistry Lab

Ocean microbes are poorly understood and hard to cultivate in laboratories. Because microbes have such a fast lifecycle and are at the origin of the food chain for all other large aquatic species it is key to understand changes in their habitat to adapt better to climate change. One of the cool features of microbes such as phytoplankton is that they are a source of oxygen in the water through photosynthesis similar to plants. I think it is amazing to think that microbes in the ocean can behave like plants on the surface of the earth. Ciara’s hobbies at sea include bird watching and reading.

We are now closing in on the next and last part of our cruise which is to run CTD stations along Cape Farewell Greenland and then continue with the Eastern part of the OSNAP array, recovering moorings. The US research ship R/V Armstrong is also doing mooring recoveries in the vicinity and word has it we might even see each other in the coming days as a Rendevouz at Sea. Last December I already had the pleasure to visit this cool oceanographic research vessel and it will be exciting to see the ship in scientific action on the open seas!

Spare Time

by Heather Furey

Well, this cruise has been singular – definitely the best weather for deployments and recoveries that I have experienced while at sea.  I’ve been noticing the things folks do in their spare time.  Every cruise is different; every cruise has a different feel to it.  The different people and personalities and work experiences coalesce into a singular experience. 

On this cruise, I have learned that I am not awful at crosswords!  Every day, Collin Dodson prints out a stack of the most recent New York Times crosswords, and people work on them through the day.

Two photos of people sitting at desks in the main lab and working to complete crossword puzzles.

Every single person in the lab working on the exact same New York Times crossword at the same time.

Dave Wellwood has a disco ball in his salt lab, and music. 

Keenan Foley has been trying to keep a stowaway bird alive by providing it a little bowl of water.  We think it might be a juvenile Ringed Plover? 

Two photos: at left, a small brown and white striped bird, about the size of a person’s hand, standing on the back deck of the ship; at right, the bottom portion of a small water bottle cut open and holding fresh water, put out on deck for the bird.

A stowaway bird (maybe a juvenile ringed plover?) has come out to visit for each mooring deployment. We think it has been on board since we left port. Keenan’s fresh water supply for the bird is pictured to the right.

The science party made cups to shrink, a tradition. Regular sized cups, when put under great pressure – as happened when being pulled deep underwater, will shrink to cups a quarter or so of their original size.  We decorate cup with sharpies and tie them to the CTD rosette cage for a ride to the bottom of the sea.

Photo of a white sheer laundry bag with colored Styrofoam cups inside. The bag has been attached to the rosette frame with tie wraps, and waits on deck for the next CTD cast.

Decorated cups in a laundry bag, tie-wrapped to a rosette frame, ready to be brought to the bottom of the ocean.

And James Kuo has been working his rope skills.  It’s James’ birthday today, and Eric made a special cake, James (an experienced winch operator) got to run the Lebus winch and drop the last anchor on the last deployment. 

The OSNAP portion of this cruise is almost wrapped up. We have had four successful mooring deployments thanks to a great crew, and we have just one more sound source mooring to recover.  It is time to savor the last few days at sea, the simple skyline. Time to get things documented and submitted, work out agent and shipping logistics, to dream of fresh green vegetables, and of heading home.

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