Day 7: GLAD Expedition – Aquarium-State-of-Mind

Day seven of GLAD has been filled with all things Gulfport thus far. The day’s first development was the (scheduled) addition of a 12th member of the science staff: Darek Bogucki out of Texas A&M University. Quickly on the heels of his arrival came the presentation/question session with members of our funding agency, the Gulf of Mexico Research Initiative (GoMRI), and reporters/cameramen from local news organizations. Topics at the session ranged from drifter construction and deployment to the bigger-picture impact of the GLAD and CARTHE in general.

The guests were friendly, asked questions, listened attentively, and stayed a long time. Being isolated for just over six full days had put me in a bit of an aquarium state of mind, so it was good having other people come along when they did and tap on the glass. After the tide of reporters and administrators had receded, Gulfport beckoned from across the shipyard’s vast and hot expanse. The allure of lunch away from the Walton Smith had absolutely nothing to do with escaping our own cook’s meals. Rather, the prospect of testing claims of oyster excellence (and the opportunity for a change of scenery) proved powerful enough to spur on our exodus. The oysters were pretty darn good. And I daresay that my locally-made brown ale was among the better brews I’ve tasted. Good work, Mississippi.

Post-lunch activities involved planning for the imminent drifter hunt (and high-resolution GT-31 GPS recovery) for the PVC members of yesterday’s “S1” deployment. Aye, our next task is somewhat of a wild goose chase- one where the geese are taped and strapped to the tops of floating plastic tubes that obey the fickle whims of salinity gradients. At least our geese are equipped with flashing LEDs and honk at our satellites once every five minutes. That much is reassuring.

Dr. Brian Haus and I took advantage of the dock’s proximity to the ship to calibrate and co-locate our cameras. After creating a two foot by two foot grid and positioning it within the cameras’ field of view, we measured the distances and angles required for further calculation. Plainly put, this step will allow us to project the rectangular image captured by a camera into its actual footprint on the water’s surface. Since we can’t suspend the cameras directly above the area being sampled, this step in the calculations is essential if we’re to extract physically meaningful information from our recording devices.

Polarimetric camera with our grid in its field of view

Photo taken at the same time as the previous one but with the infrared camera. Note the difference in scale and position. That, along with the apparent deformation of the grid based on angle and position relative to the camera lenses, will need to be accounted for in the final calculations.

The Walton Smith requires a bit of work that can’t be done out in the Gulf, so we’re dockside for the near future. I suspect that we won’t linger too long into the evening, but deadlines and schedules on these sorts of journeys can and will change without too much notice.

Nathan Laxague signing off (somewhere between Biloxi and the bayou).

Day 6: GLAD Expedition – 2 boats, 5 hours, 90 drifters…

Two small boats.

Five hours.

Ninety drifters.

The time from breakfast to lunch was filled with the long-awaited “S1” deployment.

Using nothing more than our small boat’s compass and our own mariners’ intuition (with some pre-loaded GPS waypoints on a hand-held Garmin), we dotted our little patch of Gulf with a third of the payload.

The small boat “Tatiana” being loaded. R/V F.G. Walton Smith crew members pictured are Bill (L) and Mike (R) (Photo by: Nathan Laxague)

Both loaded small boats. (Photo by: Tamay Ozgokmen)

“Tatiana” retrieving drifters offloaded by the Walton Smith before its deployment run (Photo by: Nathan Laxague)

As described in Day Four’s edition of the “Daily CARTHEan,” the famous “S” deployments are done in ten parts. Each part, or node, contains three pods of three drifters apiece. One pod per node is taken care of by the Walton Smith itself, while the remaining two are divided between two independently operating small boats. When a new node is begun, both boats return to the Walton Smith for re-stocking of drifters. “S1” down. “S2” and “S3” to go.

Plan for the initial “S1” deployment (and rubric for “S” deployments to come). (Image by: Ed Ryan)

At the time of my writing this, our journey is taking us north to the city that never sleeps- Gulfport, Mississippi. Estimations have us reaching those pristine shores sometime late tonight or early tomorrow morning. The Walton Smith needs precious fuel and its cook needs precious produce. Mike, our on-boat technician, requires more cotter pins for drifter construction, so it’ll be good to stop off. I’ve also heard that Gulfport has good oysters. Hopefully we can test these claims (and taste their clams).

The gap that is the remainder of our day will allow us a chance to take stock and organize data. Come Tuesday, with Gulfport behind us, we’ll take to the task of blanketing every naked scrap of deck space with another deployment’s load of drifters. But now, we exhale.

Nathan Laxague signing off (somewhere between lunch and dinner).

Day 5: GLAD Expedition – Fairly foul

Fairly foul weather greeted us this morning, making getting out of bed an exercise in balance for this landlubber. “We just passed through a squall,” one researcher told me as I staggered up the stairs. Uh huh.

In any case, our deployment schedule for the day is delayed until tomorrow (Sunday). But instead of displaced plans allowing the Walton Smith to list aimlessly like our 301st drifter, it came down from on high (Drs. Ozgokmen & Haus) that we survey the deployment area with CTD casts (conductivity, temperature, depth; the CTD bundle of instruments is lowered into the water either via rope or cable, sampling each of the three listed quantities to construct their corresponding vertical profiles). So, as I am writing this, our starboard winch is hauling up the fancy little device from its 1300 meter dive. This is the first of 16 CTD survey sites on a zig-zag pattern across the “S1” area (the remaining 15 will most likely be of a shallower sort- somewhere in the realm of 300 meters apiece).

CTD being lowered into the water (Photo by: Nathan Laxague)

The combination of a mildly windy, overcast day with the prospect of periods of the ship idling make this an excellent opportunity to capture meaningful surface imaging. Both the polarimetric camera and the infrared camera are being used in tandem with the CTD casts to provide as complete a picture of the water surface/column as possible. The infrared camera will pick up on surface heat flux while the polarimetric camera will focus on small (we’re talking centimeter wavelength-small) wave slope and structure- again useful in calculations involving surface roughness and gas/enthalpy transport.

Polarimetric imaging of the water surface – corresponding to linearly polarized light at zero degrees (Photo by: Nathan Laxague)


Polarimetric still – corresponds to light that has been linearly polarized at 45 degrees by the water surface (Photo by: Nathan Laxague)

Polarimetric image – corresponds to light that the water has linearly polarized at 90 degrees. Each of these three images is of the same area of water surface at the same time. The “polarization” part comes from where the image is copied twice over and each of the three are passed through polarization filters on their way to three separate cameras. This helps us re-construct the slope field associated with the small waves. (Photo by: Nathan Laxague)

Nathan Laxague signing off (somewhere between 800 and 1000 meters- “this is ourselves… Under Pressure”).

Day 4: GLAD Expedition – Round-the-clock

Good morning- or whatever it is. It’s still morning for me (since I awoke at the crack of noon). We’re locked into the heart of the Large Scale Survey, meaning around-the-clock drifter deployments. Every 90-120 minutes, we reach a new drop zone (there are 20 such in the LSS) along our spiral course to the Deepwater Horizon site. In addition to the 20 tall, white drifters you’ve of course become familiar with in past issues of the “Daily CARTHEan,” four flat (surface-riding) drifters are being deployed to go along with four meteorological drifters that will report to NOAA for a period of several months.

(Photo by: Nathan Laxague)

Now, onto serious matters. Lunch was a delicious sandwich of Italian cold cuts (everything from soppressata to cappicola) with fresh buffalo mozzarella between slices of buttery, golden Italian bread. As if that wasn’t enough for a complete meal, the accompanying salad was a stack of shredded basil on slices of tomato on slices of buffalo mozzarella on slices of fried (but not too oily) eggplant. Whew.

The seas seem a bit calmer than they were yesterday and last night, but they still make showering an exciting (if precarious) task. of course, this might be due less to the energetic (or lack thereof) nature of the ocean and more due to the Walton Smith (which draws around six feet of water) hauling tail from drop site to drop site.

CARTHE GLAD Mission (Photo by: Nathan Laxague)

In any case, most scientists on board are looking ahead to Sunday’s “S1” deployment, so named for the shape that drifter deployment nodes will make in relation to one another. In other words, it’s an S-shaped curve of ten nodes, each containing nine white drifters. It’ll take three small boats and the Walton Smith to complete this leg of the experiment (along with heavy radio and GPS use to keep everything in line). In addition to their inboard “SPOT” GPS units, these 90 white drifters will contain a strapped-on, Otterbox-protected “GT-31” GPS. This unit self-records highly accurate latitude-longitude data once per second to an attached 2 GB SD card. Of course, this means that the drifters must be collected once the GT-31s’ batteries have run down. To aid in said collection, water-activated LEDs (as you may have remembered from the Day 3 issue) will be attached to one float of each of the 90 drifters.

Otterbox GPS units (Photo by: Nathan Laxague)

Until this “S1” deployment comes, though, I can’t say too much regarding how it will play out. I hope for calm seas and a smooth operation. Regardless, I will fill you in (either Sunday or Monday) on the deployment’s execution.

Nathan Laxague signing off (somewhere between LSS node 11 and LSS node 12).

Day 3: GLAD Expedition – Calm before the storm… of activity

Today’s edition of the “Daily CARTHEan” will be a bit meager. It’s no accident- the furious pace at which drifter construction proceeded yesterday has left us with very little in the way of group physical labor to be done today. Attaching water-activated flashing LEDs to each of the ninety drifters in the “S1” deployment is one task, but the real work won’t begin until the LSS deployment around 8:30 tonight.

The dry lab aboard the F.G. Walton Smith is a flurry of code-displaying laptop screens (with a few reserved for composition of weather-related mass-emails). The highlight of my morning/afternoon thus far (besides the enchiladas and fried plantains I had for lunch) has probably been the reinforcing of our camera mount with even more hunks of metal and fastening implements. I shudder to think of the conditions that would loosen that sucker now.

Photo by: Nathan Laxague

Speaking of food (at least I think I was), a 30ish pound Mahi Mahi was caught this morning. In a separate, coincidental development, tonight’s dinner menu now includes “blackened mahi mahi.” Huh. I hope it’s fresh.

Look for tomorrow’s update to include a play-by-play of our first major exercise, as the deployments along the LSS ship trajectory look to take somewhere north of 50 hours from start to finish. I’m sure that each of us will be well-rested and chipper come Saturday night.

Nathan Laxague signing off (somewhere between ennui and teeth-gritting anticipation).

Day 2: GLAD Expedition – Nathan Laxague

For the first time in my life, I woke to find myself surrounded on all sides by water with no land in sight. We were definitely not in the Keys (or Kansas, for that matter) anymore. The look of the ocean had changed from its previously pale, shallow aqua to a deep and pristine cerulean.

For a span of time that lasted about half an hour after the conclusion of breakfast, we were all able to enjoy a rare occurence: outdoor weather that was more pleasant than the air conditioned interior’s. Alas, the sun did its work and quickly rendered the 01 deck a toaster oven, driving our work inside. To this end, drifter construction has certainly begun to fire on all cylinders. Every usable scrap of space on the Walton Smith’s main deck (and a significant portion of the 01 deck) is currently occupied by a tethered nest of assembled and GPS-transmitting drifters.

It hasn’t been all cotter pin cuts and fiberglass splinters, however; this morning a pod of dolphins were spotted swimming alongside the ship. Some hopped the wake off the port stern (hunting flying fish, it seemed) and one zig-zagged in front of the starboard hull.

Our position as of 19:45 GMT is a hundred or so miles west of Punta Gorda (let’s hope loose lips do not, in fact, sink ships), so this leaves us with a little more than a day to get to our immediate destination southwest of the De Soto Canyon. The modellers are taking full advantage of the time, either tapping away at lines of code or sternly looking at calculated trajectories. We’ve also gotten the drifter construction down to a tight little science and- if I may say so- the food on board remains excellent (knock on wood; dinner’s soon), so I think everyone’s in a pretty good mood. One exciting prospect for the hours to come is the installation of a marine LED array on the starboard side for night-time camera operation. I’m sure that you find the in situ data acquisition storyline enthralling, so I’ll do my best to get you the details as they become illuminated.

Nathan Laxague signing off (somewhere between wide-eyed enthusiasm and bleary-eyed weariness).

Day 1: GLAD Expedition – PhD Student Nathan Laxague Update

Day one of our intrepid expedition has gone swimmingly (figuratively speaking). As of 17:00 UTC, we were steaming down the coast of Southeast Florida under 85 degrees and 70% humidity. I assume that our hug-the-coast trajectory is an anti-foul conditions measure, but there’s a small part of me that suspects it is to maintain TV reception for some scientist’s surreptitious viewings of “Cajun Pawn Stars.”

RV Walton Smith Captain Sean Lake, along with research crew members Mark and Mike discuss the expedition.

In any case, the day has already seen safety and information briefings, installation of the starboard bow-mounted UDM (ultrasonic distance meter), and a full-blown fire drill. The drill was an absolute necessity- safety is of paramount importance for the crew and passengers of a 92 foot research vessel (to say nothing of the Vitamin D supplied to the more model-oriented scientists).

Sea-sickness, for the moment, holds no sway over your author. A quick and unofficial poll of the R/V F.G. Walton Smith’s inhabitants revealed that 100% of scientists and crew members had held onto their lunch (Cobb Salad today), so morale is quite high. In that vein, the ship’s size, stability, and amenities insulate us quite well from the rigors of life on the high seas. Few ships boast both a snow-cone station in the laboratory area and the deck space and crane capabilities to construct and deploy 300 Lagrangian drifters across an area hundreds of square miles in size.

Assembled drifters on the main deck of the RV Walton Smith

Fully assembled drifters are quite space inefficient for on-ship transport, so each of the three large deployment (90 drifters per) operations requires an assembly line for its preparation. This involves attaching the sails (these sails sit below the water line), affixing the floats, and pinning the disparate parts together for security.

The drifters will be launched from these boats which sit on the deck of the RV Walton Smith

The PVC bodies for the drifters

The drifters are assembled on the boat

Of course, a drifter isn’t worth the PVC that built it if it doesn’t contain its brain. In this case, that “brain” supplies the data that is the raison d’etre for the GLAD- a SPOT GPS unit made for two months of operation. Each SPOT (more commonly a fixture on the Appalachian Trail than the De Soto Canyon) sends its “emergency” latitude-longitude signal to our team back at Virginia Key once every five minutes. Twelve times per hour, twenty four hours per day, seven days per week, four weeks per month, two months (projected) per experiment. That’s a bit north of 16,000 real-life data points for the modellers to devour and digest. Current construction has us building the 20 drifters needed for the LSS (Large Scale Spiral) deployment that will, unsurprisingly, take our ship on a large spiral path south of Louisiana.

In situ (Latin for “in site-” evidently the Romans stole more words from the English language than we give them credit for) measurements of meteorological quantities are made through sensors mounted on our manually installed mast. Carbon dioxide and water vapor concentrations are measured through the LICOR device; temperature and relative humidity are probed with a Rotronic sensor; two separate radiometers measure incident solar radiation; a sonic anemometer measures and relays the three Cartesian components of wind velocity (incredibly helpful for air-sea nteraction calculations involving the ubiquitous “wind stress”). The UDM mentioned earlier is extended outwards across the starboard bow on a metal beam. Twenty times per second, the device polls the water surface with ultrasonic pulses, relaying to our data acquisition system wave height information (making the data ripe for wave spectrum analysis). Additionally, IR (infrared) and polarimetric cameras are side rail-mounted for measurement of cool skin effects and analysis of small wave structure.

Nathan Laxague signing off (now from somewhere near Key West, I’d imagine).

Welcome to the CARTHE GLAD blog!

The CARTHE GLAD blog site is dedicated to our Grand Lagrangian Deployment (GLAD) experiment set for July 17 – Aug 3, 2012. We will have a number of our researchers and students updating you on their experiences during and after the experiment. We expected to have updates daily!

A little background…

The Consortium for Advanced Research on Transport of Hydrocarbon in the Environment (CARTHE) led by Dr. Tamay Ӧzgökmen at the University of Miami (UM) is conducting the largest-scale experiment of its kind in the Gulf. The summer of 2012, over the course of a week, Dr. Brian Haus (UM) and his research team will deploy 300 custom-made drifters near the Deepwater Horizon site and Louisiana coast.

CARTHE crews preparing for the GLAD experiment on the deck of the University of Miami’s RV Walton Smith

The release of drifters, known as the Grand Lagrangian Deployment, or GLAD for short, is an essential first step to study the complex and elusive surface ocean currents that transport pollutants, like hydrocarbons. In preparation for the real experiment, CARTHE research teams have conducted tests, featured here, to improve drifter deployment and their decision-making process in selecting the best methods to release the drifters – a critical component for the success of this project.

Dr. Guillaume Novelli and Dr. Angelique Haza build drifters to the test deployment

CARTHE comprises 26 principal investigators from 12 universities and research institutions distributed across four Gulf of Mexico states and four other states. It fuses into one group investigators with scientific and technical knowledge and publications related to oil fate/transport processes, oceanic and atmospheric turbulence, air-sea interactions, tropical cyclones and winter storms, and coastal and nearshore modeling and observations.

CARTHE Researchers and GoMRI personnel who attended the CARTHE Kick-off Meeting in May 2012