By Eric Lindstrom
If you all are waiting to see some action at sea, I am sorry it is taking a bit to unfold. It takes about a week from Woods Hole to reach our study site at 25N, 38W. It’s good for us to have the time to check and re-check the instruments, get people trained in various procedures and ready to stand watch for 24/7 operations, and get to know our work mates. However, everyone that has prepared for more than a year for the expedition finds this week a long one. We want to be getting gear in the water and a flood of data passing through our computers. We want to be up all night, busy with deployments, water sampling, and scientific analysis. Everyday on the research site will be brimming with new data and constant planning for the next event.
The chief scientist has his hands full keeping the entire show operating smoothly. We have mooring, Argo float, and drifter deployments, glider operation, underway profiling, station profiling, autonomous profilers, and more meteorological sensors than can be easily counted. Everything needs to be working, providing good data, calibrated, checked and re-checked, and while many things can happen simultaneously, nothing should interfere with anything else.
The order of business is, very roughly, to get the sensors we want in the water (to supplement what the research vessel can do), off the ship and doing their job. The moorings and Argo floats take a lot of space and only serve us when deployed, so we will spend much of the first days on site getting these in the water. While we move from one site to another deploying equipment, we will also be mapping the ocean with instruments we lower from the ship on station or tow behind the boat while underway. During just about every moment, we try to gather data from the upper 1300 feet (400 meters), to characterize the salinity field and ocean circulation.
Once we have all our assets in the water, we can focus on using them in conjunction with the ship to characterize the ocean environment on time scales from minutes to weeks and from inches to a hundred miles. Over about three weeks we will do our best to map and understand how salinity varies at this spot in the ocean and why it does what it does. When the ship leaves, we leave many of these instruments in the water, to continue our work for the next 12 months. Expeditions in six months and 12 months from now will maintain and eventually recover many of the instruments we deploy in the coming week. We think of it as deploying a sensor web in the ocean.
This kind of intense study is the basic work that helps us understand and interpret the weekly global maps of salinity we get from Aquarius. There are more esoteric and nerdy scientific questions that get answered along the way (making it very satisfying to all the scientists involved), but everyone is highly motivated by the opportunity Aquarius offers to study the global salinity field. SPURS is realizing that opportunity.
By Eric Lindstrom
Saturday, 8 September 2012 — Given the talk around the Knorr’s dinner table, you would have to say that oceanographic expeditions run on their stomachs. Key to surviving weeks away from home and family is good food and good moods. The food on the Knorr is excellent, so we are likely to have happier people and better results. Most people will come back a few pounds heavier. There is a gym on the ship but it can be dangerous to be on a treadmill or lifting weights in rolling seas…so, more than likely most will lose the weight battle to the dining experience!
Today was the day we passed in front of the predicted track of Hurricane Leslie. We felt a bit of the swell coming from the storm, but otherwise we had fine conditions. In the early afternoon, we slowed for a few minutes to deploy the first Argo float of the voyage. Deploying the floats is pretty easy since they have all been powered up and are ready to go right out of the box. We just have to slow the ship and lower the instrument over the stern and gently into the water.
We plan to deploy two Argo floats in front of the predicted hurricane track. They will measure temperature and salinity profiles before, during, and after storm passage. In addition the profiling instruments “listen” to ocean acoustics and can make an estimate of wind speed and rain rate based on the noise of those actions on the sea surface (pretty cool!) So, we especially wanted to see how the acoustic sensors deal with a big signal like a hurricane. Steve Riser at University of Washington is the Principal Investigator for the Argo floats in SPURS.
I also received my first official science training of the voyage. We have a small device called an underway CTD for measuring a profile of conductivity, temperature, and depth of seawater. Two people will work together to deploy and recover this instrument on an hourly basis throughout most of the experiment. The device is tethered to a small winch and boom (like a fishing rod and reel) at the stern of the vessel and dropped in the water to make measurements from the surface to 400 meters (about 1312 feet) depth while the ship is steaming at 10 knots. It finishes a profile in 100 seconds and is then reeled back aboard. It is kind of like hauling in a fish with an electrically-powered rod and reel. It takes 20 minutes to haul in the beast and then another few minutes to download the data from its internal memory to a laptop computer. We plan to deploy this instrument every hour once we begin normal operations in the SPURS region next Friday.
The latest wind and wave information from Hurricanes Leslie and Michael suggest that our path to the SPURS site is just about perfect for seeing the minimum impact from the storms. The seas are still lumpy, but Knorr looks to be slipping through the gap between the storms. Fingers crossed!
By Eric Lindstrom
We knew when we left Woods Hole yesterday that we had two hurricanes (Leslie and Michael) standing between us and our study site, far southeast of Woods Hole in the mid-Atlantic. How Captain Adam of the Knorr chooses to deal with this over the next days is a study in weather and ocean forecasting – and calculated risks. We considered at least three options: delay departure until the coast is clear, make a significant departure to the cruise track (sail far south, then east), or leave on time but travel quickly to the east and then south to miss the worst of the hurricane weather.
The last option is what we are doing. We abandoned plans to do test stations and do science training for a few days so we can make hast to the east, to the east side of Leslie’s track. Then we can make our way south and around Michael. Tom Farrar and Fred Bingham of the SPURS science team have provided the bridge with Gulf Stream analyses that we hope will help us take best advantage of ocean currents in our race eastward. We could easily have found ourselves in an eddy that would hinder our progress, and no one wants that with bad weather coming toward us! It was a fabulous start to the voyage to have the crew of the Knorr and the SPURS team working so closely on the strategy to both keep us safe and on schedule.
It’s worth mentioning too that satellite data and the shore-based team play a crucial role in our cruise planning. Zhinjin Li and Michelle Gierach at the NASA Jet Propulsion Lab have been feeding us the latest satellite images from the Atlantic so we can better understand the wind, waves, and currents in our path. We rely on these contributions because it is difficult to surf the web from sea – we have Internet access, but it can be quite slow.
Today we feel the enormous forces of the tropical storms on the western Atlantic. There is a good swell running – speaking clearly of some strong wind at a distance. Some aboard are feeling seasick, but the mess is still full of hearty eaters and smiling faces!
One of the things you notice in these conditions are all the items that can shake, rattle, squeak, groan, or otherwise move and make noise. I have been up and down in my cabin a number of times during the night to silence rattling cupboard doors, toppling books, sliding glasses – it’s almost an endless battle. At sea you don’t just put something down – you secure something, wedge something, pad something, or it becomes something broken, lost, dangerous or just plain noisy! Sometimes one even has to wedge oneself in a place and just stop moving around! All of us have greater appreciation than most for the stability of land and the silence that stability brings. When things are shipshape, all is secure and in its place. We are living shipshape today.
By Eric Lindstrom
We had a whirlwind of preparations after the Labor Day Weekend. All the gear was loaded on the ship and lashed down. The scientific party (22 people) arrived and set up in various spaces around the ship. Bill Ingalls, a NASA Headquarters photographer, captured many great shots of the Knorr and the equipment. His photos are online at NASA Headquarter’s Flickr account.
I also had the pleasure of meeting Naomi Harper, a teacher from Will Rodgers Middle School in Fair Oaks, CA. She was visiting Woods Hole and stopped by the ship. I am looking forward to interacting with her students via this blog during the voyage.
We cast off and set sail at 8:30 a.m., on Thursday, Sept. 6. While it’s a very beautiful calm day, we know that we have storms in the Atlantic between us and our destination (Hurricanes Leslie and Michael). The cruise plan is being adjusted a little so we spend the first few days focused on “outrunning” the storms. We can do out test stations and other such preparations after we have reached calmer waters west of the hurricanes. So, we are expecting rough seas at some points during the next few days and the first order of business as we set sail is to get all our gear secure on deck and in our cabins. Everything that can move needs to be secured before we face the storm waves.
There was a nice gathering of friends and family at the wharf to see us off on our voyage. We are lucky to have such a beautiful sunny morning and calm winds for the send-off.
Thirty minutes after setting off from Woods Hole, we have our first meeting of the entire scientific party. There are people from several institutions and we all need to put names to faces. There are also scheduled safety meetings and boat drills during our first day and before we leave the calm waters of Massachusetts behind.
The only scientific work planned for the first few days, as we race past the storms, is regular sampling of surface waters to calibrate the ship’s thermosalinograph. This instrument monitors ocean temperature and salinity continuously from water coming in through a port in the ship’s hull. It will operate continuously during the voyage, but we need to collect calibration samples every 4 hours for precision salinity determination.
We are all learning about the rhythms of shipboard life. We will have people on many different watch schedules. The watches will operate on local time. That shifts as we move east across time zones. As your blogger on the SPURS cruise, I plan to float across different groups and schedules as the expedition progresses to give you multiple perspectives. On the ship, meal times are very important. We will have breakfast every day from 7:30 to 8:15 a.m., lunch from 11:30 a.m. to 12:15 p.m., and dinner from 5:00 to 5:45 p.m. I’ll let you know more about the delicacies we eat at sea!
By Eric Lindstrom
The SPURS experiment involves not only sea-going oceanographers but modelers, and of course, remote sensing scientists using satellite data. As part of the daily posts from R/V Knorr I will go into more detail on the role of the models and satellite data in the overall scientific enterprise. I will profile the modeling teams and their interaction with the ship-based team during the voyage.
Numerical models of the ocean, run on supercomputers, can provide high-resolution animations of the physical environment for us sea-going scientists. In order to actually simulate the environment, the models need to take in data from the expedition and make sure the model solution is one that best fits the available data. This process is called data assimilation. (You are more familiar with data assimilation in models than you think – daily weather maps are the result of models and forecasts are done using data assimilation into sophisticated models of atmospheric physics.)
An objective of SPURS is to provide a high-resolution, near-real-time stream of data that can be assimilated into ocean models. Because the ocean is so big and complex, and our at-sea capacity to measure it so puny, we rely on ocean modeling and data assimilation to help us interpret the environment. The model results can be used in planning work at sea and to diagnose the balance of salinity in the upper ocean. The observations are essential to locking model results into the real oceanographic environment. The model is essential to estimating things we cannot measure directly and expanding upon the interpretations provided by the observations.
In SPURS, we hope that we scientists at sea and those ashore can collaborate through the exchange of data and model results. This was not possible as late as a decade ago. Now we have Internet at sea and can exchange information and results for daily planning and analysis.
I will discuss the synergy of models and data much more during posts from the ship in September.
SPURS as an International Enterprise
The SPURS experiment involves a number of expeditions and nations working in cooperation at the single location in the North Atlantic.
The French R/V Thalassa is in the SPURS region now with one U.S. team aboard from University of Washington’s Applied Physics Laboratory. I will give more details in future posts.
Follow-on U.S. expeditions will use R/V Endeavor from University of Rhode Island to follow-up the measurements of R/V Knorr. The first of these two expeditions is in the spring of 2013 and will service SPURS equipment that requires maintenance after 6 months at sea. That expedition will also do more of the “feature” characterization. A second expedition in the fall of 2013 will recover all the moored equipment and gliders, among other duties.
A Spanish cruise is also planned for next spring. The details of this expedition will be subject of a post.
What’s up next?
Next up will be the loading of R/V Knorr on 5 September and a media event at 10 am that day. We set sail on 9/6 at 10 am.