Christmas in Newfoundland

Brad deYoung, Robin Matthews and Mark Downey
Physics and Physical Oceanography
Memorial University, Newfoundland
11 January 2017

This fall we deployed an ocean glider into the Labrador Sea.  Our goal was to make measurements of the oxygen and carbon dioxide gas  properties in the Labrador Sea.  There are presently two deep-sea moorings in the Labrador Sea, separated by about 40 km off the shelf in 3500m of water.  The K1 mooring was deployed by German researchers from GEOMAR in Kiel; the Seacycler mooring was deployed by Dalhousie researchers as part of the VITALS research program. We wanted to map the gas and water properties between and around the moorings.  The glider operated from the surface down to 1000 m depth, flying along a 100 km extended line that connects the two moorings.

Our original plan was to deploy the glider directly in the Labrador Sea from a research ship  and then recover it from a ship in the Labrador Sea, so that we would get the most  out of the batteries in the glider. Battery-power is time, and time is money of course. We wanted to get the most out of our battery investment. As it turned out, the availability of ships did not line up with our schedule. As a result we had to deploy from the shore in southern Labrador, the closest port to the Labrador Sea. For recovery, southern Labrador would not work because by December all the ports are closed because of ice. So we had to fly the glider to the south and recover from the island of Newfoundland.

The deployment in September required driving  1400 km from our lab, in St. John’s Newfoundland, to Cartwright Labrador, about a day and a half of driving that requires taking a ferry from Newfoundland across the Labrador Straits to Labrador. We deployed the glider using a 63 foot boat operated by a local fisherman.  Operating from small boats does have some advantages, making it easier to get the glider into the water. Even in September the weather was intense. On the afternoon of the deployment, winds over the shelf reached 55 knots and the sea was about 8 m or 25 feet.

Mark Downey getting the glider ready for deployment with the Gannett Islands in the background.

Mark Downey getting the glider ready for deployment with the Gannett Islands in the background.

 

The glider did move across the shelf fairly smoothly (see below) although you can see from the track that there was a period when the glider was too shallow and got caught in a strong southward current and was pulled southwards. Once off the shelf and the glider could dive to its full 1000m depth thus was able to make better progress and only took a few weeks to reach the mooring stations. The glider operated in the Labrador Sea very well and flew for three months operating along the extended line between the two moorings.

The intent was to fly the glider straight across the shelf but strong currents, and a little mixup in the depth of the glider, led to an unintended loop to the south.

The intent was to fly the glider straight across the shelf but strong currents, and a little mixup in the depth of the glider, led to an unintended loop to the south.

In November we began making plans for the recovery. We carefully watched the battery usage. Each day the glider would use about 0.5 percent of the battery. That meant that in principle we could have 200 days at sea but in practice we want to recover with 15-20% of the battery left in case there are delays on recovery or the battery is not as ‘full’ as we think it is. We made a plan to fly the glider along the shelf edge where the water is deep and where there is a strong shelf break current moving southwards. The southward current meant that we gained an extra 10-20 km of progress. We determined that it would take about 40 days to fly the return route and so headed the glider southwards in mid-November (see track below). As the track shows, the glider made its way southward very well in spite of a few hiccups. At times we would lose regular contact because the winds (greater than 50 knots – 80 km/hr) and sea-state (well above 10 m – 30 feet) were such that the antenna was not always working properly. We also had some problems bringing the glider back across the shelf when it appeared to lose track of its direction a bit, perhaps related to problems with how the glider corrects for the current that it experiences as it flies.

Return path of the glider from the Labrador Sea a trip that took about 40 days and led to the successful recovery of the glider just off Heart’s Content, Newfoundland

Return path of the glider from the Labrador Sea a trip that took about 40 days and
led to the successful recovery of the glider just off Heart’s Content, Newfoundland

We planned to bring the glider back to one of the deep bays on the north coast of Newfoundland – Trinity Bay. These bays are somewhat sheltered and because they are deep the glider could wait there for us, patiently going back and forth in the deep water. The glider arrived at our target location off Heart’s Content, Newfoundland on Christmas day. We programmed it to fly a little triangle offshore (see figure) and then went out in a small boat to recover it. On the day of the recovery the pilot for our mission (Robin) was in the UK and so while he maintained contact with the glider we got the boat ready and then went out looking for the glider. The day before we had a storm with strong winds and the day after we had a strong winds again and so we had a narrow window for the recovery. It was winter and windy but we had no problems as we knew precisely where the glider was. The glider was just where we expected to find it and the weather cooperated. Now we get to explore the data and plan for our next deployment in the Labrador Sea.

The glider (located just below the boom in the center of the picture) was just where we expected it to be on a somewhat windy and very cold data. The glider looked just as bright and clean as on its deployment some four months earlier.

The glider (located just below the boom in the center of the picture) was just where we expected it to be on a somewhat windy and very cold data. The glider looked just as bright and clean as on its deployment some four months earlier.

Posted in Cruises

What I love in observing the oceans

by Loïc Houpert

So today, I decided to contribute to the blog by telling you what I like in my work as an observational physical oceanographer.

I am working as a postdoc at the Scottish Association for Marine Science in the beautiful and “occasionally” wet town of Oban. Being a physical oceanographer, I am generally interested in understanding the ocean’s circulation, but right now my interest is more focused: how is the ocean’s heat carried by the currents in the North Atlantic and where is this heat going? The transports of heat and also freshwater by the North Atlantic current system are particularly important for the temperature, precipitation, and wind patterns and strength over the European continent. In my research, I am using autonomous instruments (underwater glider and fixed instrumented lines) that continuously record the state of the ocean.

Going at sea to take measurements and deploy/recover instruments is definitely the best part of my work, although stressful at times. But after coming to shore, the most interesting part of the job is to actually unravel all these big datasets and try to identify physical signals that are associated to the dynamic of the ocean. In addition to having good knowledge of physical oceanography, several factors are important when working on observations: curiosity (being interested in seeing what is in the data), imagination/intuition (finding a way to put together the different pieces of the puzzle) and of course a little bit of skepticism (test the results’ robustness again and again …!).

I really choose to become an observational oceanographer in the second year of my Master, during my research project. It’s true that I had some second thoughts after my first sea-going experience as I was very sick for most of the time of this 7-day cruise… However, 8 months later, during my PhD, I took part in my second cruise and everything went (surprisingly) well. Of course some days were more bumpy than others, but at the same time, this 3-week cruise was in the middle of the Gulf of Lions in winter to sample the impacts of strong storm and deep (2000m) vertical mixing on the marine ecosystems…. All of this to say that you should never stay on a bad first experience when going at sea. Tenaciousness… this is also a good quality if you want to analyze ocean observations!

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Illustration 1: Myself blinded by the sun taking a (bad) selfie with Estelle, Karen (the two SAMS glider experts) and Bowmore (the pink glider) after its recovery on the DY053 cruise in July 2016, over Rockall Plateau.

 

Posted in Student/Postdoc Blog

Irminger Current time series is making music

by Stelios Kritsotalakis

The Irminger Current (IC), a branch of the North Atlantic Current (NAC), carries warm and saline waters poleward in the subpolar gyre and as such contributes to the upper limb of the Atlantic Meridional Overturning Circulation (AMOC). The Irminger Current (IC) has not been extensively studied in the past. Little is known about the velocity structure, the transport and the variability of this current. My work was based on the first year-round data from a full-depth mooring array in the eastern Irminger Sea (west side of Reykjanes Ridge). This data was recovered in July 2015 during the second leg of OSNAP 9 East cruise (64PE400) under chief scientist Laura de Steur. I was lucky to participate in this cruise and gain my first sea-going experience on board of the research vessel Pelagia (NIOZ). Results from this study are materialized in my master thesis and will contribute to a paper to appear in 2017 in collaboration with my supervisor Laura de Steur and research scientist Femke de Jong.

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Figure 1: Map showing the location of the four moorings in the Irminger Sea.

Sometimes science is a lot more art than science and sometimes music communicates science better than a figure. During my research study, I shared a flat with Nika Pasuri who is an upcoming electronic music composer from Georgia. We soon realized that we were both analyzing time series for different purposes. For example, I was analyzing the spectra of time series to discover their dominant periodicities while he was using spectral output to create sounds. And so, the idea of making music out of the mooring data was born which in turn gave birth to two songs, “RAFOS Floats” and “Loneliness of Acoustic Doppler Current Profiler”. These songs where made out of the time series of the volume transport of the Irminger current. You can enjoy them and share our excitement about this project in the following link:      

https://soundcloud.com/nikapasuri/sets/transport-and-variability-of

Stelios Kritsotalakis, Master student in Climate Physics, Utrecht University

Nika Pasuri, Master student in Music Composition, Amsterdam Conservatorium

 

Posted in News

Numerical models, in-situ data and research cruise plans

Tillys Petit, PhD student (who also enjoy the view from my office, figure 2)

Nowadays, numerical models are increasingly used to understand and predict climatic issues such as global warming, rising sea level, or shift of oceanic circulations. To answer those questions, numerical models compute a collection of data from an initial setup, allowing us to first visualize the actual state and then the evolution of the temperature, sea level or oceanic circulation around the world. But how can we know if the output is/will be in agreement with the reality? To validate a numerical model, we still have to compare the actual state given by the model with its in-situ observations. But in-situ data are still too often lacking, and cruises are thus carried out. The new set of data is firstly analysed to document the general circulation and to identify new mechanical processes, and secondly used as benchmark for models.

Currently my work is to document the oceanic circulation across the Reykjanes Ridge (South of Iceland) where very little data is available. A strong current-bathymetry interaction could impact the circulation, hence the need for better understanding of this process. To fill this gap, a cruise (RREX) was carried out in June 2015 and another is planned in July 2017. During the 2015 RREX cruise, a lot of new in-situ data were obtained along 4 sections (figure 1), such as velocity of the flow and salinity-temperature-oxygen profiles. Moorings were also deployed and will be recovered during the second cruise. Up to now, I have studied the data of the first cruise, which are of good quality, allowing us to fully address our scientific objectives. Because I was not on board in 2015 I cannot tell you how the cruise was, but I will certainly keep you inform of the general ambiance during the second!

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Figure 1: Map showing the hydrological station locations during the RREX cruises.

tillysblog_2

 

Posted in Student/Postdoc Blog

Back to school and starting-up the new modelling sensitivity studies

by Laura Castro de la Guardia

When I am ask by friends: What is it that I study? I generally give them the quick answer: I study biological-oceanography at the University of Alberta. But when they look-up “University of Alberta” on Google map for example (Figure 1), they  always point out: there are no coastlines near the University of Alberta! In fact, the province of Alberta in Canada, has NO coastlines at all. So, how is it then, that I can study the oceans?  Although one way will be to spend a lot of time travelling to either western, eastern or northern Canada to do my field work, I can also study the oceans from my own desktop at university!

I use a mathematical model on the computer to create a virtual ocean with some biology and chemicals; it is sort of like a video game, but the model attempts to be as realistic as possible. The core of the model is based on the most current understanding of physical and mathematical relationships that exist between the ocean, the atmosphere, the sea ice and the biology.

There are many models available. The ocean model I used is called NEMO (http://www.nemo-ocean.eu/) that comes together with a sea ice model LIM. The biological and chemical model I used is embedded within NEMO and it is call BLING (https://sites.google.com/site/blingmodel/). Cool names acronyms, right?! Both models are free to use by any user, but it requires some understanding of computing science, programing, and a very powerful computer. We have to run our model on super-computers that are shared across Canada  (Compute Canada/Calcul Canada).

Unlike what you may have imagined from my video game analogy, the output of the model is not a movie, but lots of numbers (a.k.a simulated data). The “simulated data” is what I use to do statistical analysis of many different things, for example, I can see the current state of the ocean, or the sea ice, or the marine algae (phytoplankton). We can also make movies with the simulated data  (e.g. http://knossos.eas.ualberta.ca/vitals/outcomes.html)

Although models are still not able to reproduce an identical ocean to our real ocean, one of many advantages of an ocean model is that I can study how one single event/phenomena/or property in the atmosphere affects my simulated ocean  or biology. This type of studies are called sensitivity studies, and they are like experiments in a lab. This is important because in our current climate, many things are changing at once (for example in the Arctic Ocean, sea ice is decreasing, temperature is increasing, the rate of river flow into the ocean is larger, there is more rain, there are more storms during the autumn), but we only observe the response of the oceans to all changes. While with the model I can have the response of the model to all changes, but also the response of the phytoplankton to only one change (e.g. more storms during fall (Figure 2)). Depending on what I am studying, I can then answer which of all these changes is the most important, which one is the one I should be most concern with? These are the kind of questions I would like to focus on for my sensitivity experiments, because these questions can help us prepare for the changing future: e.g. they could help shape or guide the adaptive tactics and conservation programs.

picture1

Figure1. Google map showing the locations of the University of Alberta, Canada.

 

picture2

Figure 2. A simulation with storms (a) compared to a simulations without storms (b). The differences between each panel shows the regions where the storms have a greater impact on phytoplankton.

 

Posted in News

OSNAP Logo Contest

Calling all OSNAP collaborators and inspired oceanographic community members! OSNAP is looking for a new visual identity and is seeking your help in designing a creative logo.

How to Enter the Contest
The contest begins on October 1, 2016. Submissions will be accepted through November 15, 2016. Winners will be notified, and announced via our website and through social media. In order for your entry to be submitted and reviewed, please follow the details below:

  1. Submit entry to Sarah Clem (sarah.clem@duke.edu)
  2.  Submit the entry in its original source file and
  3. Submit as a pdf with 300 dpi or higher.

Logo Requirements

  • Design: The logo will be featured on our website, on our social media platforms and other media (e.g., research posters and t-shirts). Thus, we want the logo to be eye-catching, but also legible. Also, the logo should be easily reproducible and scalable for large and small formatting.
  • Color: Any colors may be used. However, the logo should look good in color (if used) and in black and white.
  • Integrity: Logos cannot contain copyrighted material. Logos must have been created by the contestant(s). Logos may not include images or licensed images that have been previously published.

Contestant Agreement
The winning contestant must agree that OSNAP can use their logo for future publications and outreach applications. Additionally, the contestant must agree that OSNAP can alter, modify or revise the logo as it sees necessary. OSNAP reserves the right to not select a winner if, in its discretion, no suitable entries are received.

Prize
Contest winner will receive an Amazon Gift Card (and bragging rights!).

Posted in News

OSNAP Challenge

We want to bring everyone’s attention to the launch of the OSNAP Challenge located on this site under News and Events. Anyone is welcome to submit a prediction (or technically a hindcast because the data have already been collected) for the first two years of AMOC data from the OSNAP line. This contest is similar to the one organized by the RAPID program last year but in this contest there are no past observations of the AMOC from the OSNAP line so the level of difficulty is higher!

We are going to open up this blog to write-ups of the methods from each prediction and will be announcing the winners here in the Spring. The deadline for the submissions is April 1st. For more information including instructions on how to submit a prediction and how the submissions will be judged, see the site here.

We wish everyone luck and may the best model win!

-Nick

Posted in News

OSNAP Publication in BAMS

OSNAP collaborators have a produced a new paper for publication in the Bulletin of the American Meteorological Society. An early online release version of “Overturning in the Subpolar North Atlantic Program: a new international ocean observing system” is currently available on the AMS website:  http://journals.ametsoc.org/doi/abs/10.1175/BAMS-D-16-0057.1

Posted in News

Home again, with instruments recovered, moorings re-deployed, and data safe and sound

by Penny Holliday

 We’re steaming through Southampton Water on a hot, sunny day, and as we near the dockside at NOC we’re reflecting on a successful and enjoyable cruise.  We were very lucky with the weather, and that, combined with the work by our highly skilled team of people on board, meant that we have achieved all our scientific objectives.  I’m very pleased with the excellent quality of the data that we have collected, and with the new friendships we’ve made.

 The OSNAP moorings are now starting a 2-year long period in the deep ocean collecting lots of precious data for us – and some of us will be back to retrieve them in 2018.  Meanwhile, we’ll be busy analysing the data we’ve collected on this trip, and looking forward to going to sea again.

 DY054 Team Photo

Photo by Penny Holliday

Posted in News

Caffeine consumption among the DY054 science team (The Great Caffeine Experiment)

by Ryan Peabody

Scientists and marine technicians have long appreciated the productivity-increasing role of caffeine [citation needed]. However, quantitative assessments of caffeine consumption and usage among the members of the DY054 science team have not yet been performed. Herein, we perform a not-quite-exhaustive nine-day analysis of tea and coffee consumption on the RRS Discovery. No significant trends were observed, other than a general preference for tea over coffee, and a sharp decrease in enthusiasm for the study as it progressed. Further work is needed to determine whether or not bush tea counts as a cup of tea, and exactly what quantity of coffee counts as a colloquial “cup.”

 Data were self-reported via “marker and whiteboard,” following methods developed in Mrs. Cooper’s second grade class [Cooper et al., 1999]. Logging was originally intended to take place daily at 23:59:59 UTC, but the lead scientist occasionally felt “really over it” and data were not recorded until the following morning. Efforts were taken to ensure that subjects maintained standard patterns of caffeine consumption, though it is worth noting that several believed the study to be a contest to see which one of them could drink the most coffee.

 Coffee and tea consumption demonstrate a general downward trend over the nine days, both passing a Mann-Kendall test (Figure 1). A 0.377 coefficient of cross-covariance implies that coffee and tea consumption are not related at any reasonable confidence level. Tea was consumed in generally higher quantities: on average 2.1 cups/person/day to coffee’s 1.6 cups/person/day. Further study is needed to determine if this is standard on a British flagged research vessel. Initial data supports this hypothesis: American-born members of the science team consumed 2.8 cups coffee/person/day and 1 cup tea/person/day, while British nationals consumed 1.3 cups coffee/person/day and 2.2 cups tea/person/day. The sole Hungarian-born member of the science team consumed an average of 6.1 cups of tea per day and 0 cups of coffee.

 Over time, a noticeable lack of enthusiasm for the study is evident, with participation dropping from 14 initial participants on day 1 to 6 participants on day 9 (Figure 2). On a ship with 45 crew and scientists on board, this represents a drop from “low” to “very low” participation. Despite the decrease, 70% of participants reported feeling “fair” to “good” about their own caffeine consumption and the study, indicating that maybe no one was really paying attention to the study in the first place. A least-squares fit of a nonlinear model of form b(1) + b(2)*exp(b(3)*t) represents the data very well, but also indicates that it was wise to end the study on day 9 (Figure 3). If the study had continued until the scheduled arrival in Southampton, approximately -15.5 responses would be logged each day, indicating that study participants would begin to erase the previously collected data, invalidating the entire study.

 Clearly, further study is needed to determine: 1) exactly how much caffeine is being consumed on board, 2) why no one wants to log their daily caffeine consumption, and 3) whether or not this was a good use of my time. Caffeine is a widely-consumed but little-studied product in the context of oceanographic research vessels, with most scientific effort going toward measurements of physical, chemical, and biological properties of the ocean. Though oceanographic research vessels are built and used primarily for the latter three areas of research, there is no apparent reason not to also study caffeine consumption.

160812_DY054_Number_of_cups_of_tea_and_coffee_per_day160812_Number_of_respondents160812_Predicted_number_of_respondents  

Images by Ryan Peabody

 

Posted in News

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