Day 17: GLAD Expedition – Thank you and Goodbye… for now!

The penultimate day of the cruise is upon us (and it came with little fanfare). The drifters have been deployed. The CTDs have been cast. The fresh fruit has been eaten. This morning, the outhouse was emptied and the meteorological-sensor mast was skeletonized. Afternoon excitement included fellow student Conor catching an almost three-foot blackfin tuna (which will become dinner) while heading towards the Tortugas. An especially noteworthy part of the catch was watching the ship’s engineer cut out the tuna’s heart (while it was still beating) and eat it. It was like watching the second Indiana Jones movie, but without Short Round or Steven Spielberg’s horrendous girlfriend. I’d like to tell you how jealous you should be right now, but I’ve reached my pun quota for the day, so we’ll just leave the story at that.

We are currently south of the Keys between Dry Tortugas and Marquesas, screaming along at 10 knots (that’s rather brisk for the Walton Smith; speed over water is typically 7 knots). The loop current has been kind to us thus far, and the idea is to ride it into the Gulf Stream. I don’t think a trip to Key West is in the cards for this journey. It’s just as well- I’m a bit eager to get back to Miami.

Because tomorrow looks to be a shortened day on the ship (the whole “arriving at dock” thing), now seems like just the time to do some “thank-yous.”

First- to GoMRI, for their funding and support of the Grand Lagrangian Deployment and CARTHE as a whole.

Second- to Drs. Ozgokmen and Haus (CARTHE director and GLAD chief scientist, respectively) for the organization and execution that made this experiment possible; to Julie Hollenbeck for her P.R. work (and for allowing me this online forum!).

Third- to Drs. Olascoaga, Reniers, Lipphardt, Bagucki, and Novelli; techs Mike and Mark; fellow students Matt and Conor (all the other scientists who shared the cruise), for a fun and enlightening experiment.

Finally- to Captain Lake; to Bill, Mike, Denis, Dave, Troy, and (of course) Lynn, for putting up with (and even enabling- yikes) our strange whims and requests.
Nathan Laxague signing off (I would say into the sunset, but we’re heading East, so use your imagination).

Day 16: GLAD Expedition – Heading Home

Batten down the hatches; we’re heading home. A myriad of inconveniences relating to currents and conditions have made the final GT-31 recovery a fool’s errand. As such, we are eastbound and down on the famous loop current. Next stop: Virginia Key. The day’s tasks have therefore been more of a bookkeeping/computer work nature. I had the duty of transferring the time and position data from the hand-written CTD logs into a computer spreadsheet. It isn’t exactly hair-raising work, but it’s necessary (and manageable with the right soundtrack- Dr. Bruce Lipphardt kept us supplied with Grateful Dead and Cat Stevens tunes throughout the morning). Other work has included working in MatLab on functions and scripts that will make sense of the other data (namely imaging). I highly recommend Dr. Billy V. Koen’s MatLab tutorial series. You can learn at your own pace (with step-by-step instruction).

Anyways, the french toast breakfast came as promised. I can’t say that I’ve ever had french toast made from challah and croissant slices before. I can say that it was wonderful, however. Sweet, dense, and buttery, it was the kind of treat you don’t expect to get on the last leg of a research trip with a limited pantry and 18 hungry mouths. The real maple syrup (none of that ‘pancake syrup’ garbage) deserves high marks as well.

As of 4:30 EDT, our ship is approximately 200 miles west of Punta Gorda. Hopefully we can avoid the 10-foot seas I heard have been developing in the NE Gulf region. Those would put hair on my chest- for all of F.G. Walton Smith’s charm, she wasn’t built for that kind of excitement. We’d probably lose anything that wasn’t bolted down (including our meals).

I’ve got some data management to do up in my little outhouse (no, it’s not a spare head- it’s just a deck-mounted ice-fishing hut that houses our shipboard data acquisition). That will require my abandonment of blogging duties for the day in favor of file transfers upstairs (don’t worry- Western Digital does most of the heavy lifting). Thank you for your continued readership on even this most mundane of days.

Nathan Laxague signing off (somewhere between some task or another and watching fellow Nathan Nathan Adrian winning gold for USA in the 100m freestyle).

Day 15: GLAD Expedition – Farewell drifters!

Today was the day we bid farewell to our last drifter. I am told it was a bittersweet moment (not really). I missed it on account of sleeping in- late nights on deck can take it out of you. The groundwork for this morning’s final deployment (an inverted “L” on our cyclone) was an all-night, nine stop CTD transect spanning 60 km. Each of the CTD casts plunged to about 750 meters, so it seems like we have a pretty exciting body of data to work with from here on out.

Just two short weeks ago, every scrap of deck space was occupied by PVC bodies, floats, construction materials, and the large boxes of Coast Guard drifters we were to deploy. Now the time has come for a little R&R (research and recovery…). In about four hours, we will have reached our final CTD survey waypoint (an additional survey spot designated by the Naval Research Laboratory) and be well on our way back east. The idea is to pass through the location of the 27 GT-31 laden drifters from S2 and scoot back to Miami. Maybe we’ll be lucky enough to hitch a ride on the loop current.

On the lighter side of things, lunch was a reeeally good BLT on challah bread and the dinner bell JUST rang. I’ve been told that tomorrow’s breakfast will include french toast. For me, that’s reason enough to be excited. So, in the interest of warm food, I bid you adieu.

Nathan Laxague signing off (somewhere between writing another food-related paragraph and getting my food stolen from me).


Day 14: GLAD Expedition – Cyclone Hunters

Today is cyclone-hunting day. Don’t worry- it’s not nearly as sinister or dangerous as it sounds. The kind of cyclone that we’re eager to meet is a circular current 50 km in diameter with flow speeds of up to 40 cm/s. In other words, it’s no menacing maelstrom; rather, it is a counterclockwise-rotating feature that was very recently spun off the Gulf’s loop current (much in the same way that “Frasier” was a spin-off of “Cheers”).

The ship’s on-board ADCP has been crucial for this exercise. Using this sensor, we are able to view a real-time stick plot of the local currents (corrected for the ship’s velocity, of course). The ADCP retrieves data up to a water depth of 750 meters, so we are in a position to get a pretty good picture of the gyre’s behavior.

Also of interest to this portion of the experiment is the data collected by oil rig-mounted ADCPs. Until rather recently, such data was proprietary (and closely guarded by the likes of Shell, Chevron, etc.). Nowadays, it can be publicly accessed through Texas A&M’s GCOOS (Gulf of Mexico Coastal Ocean Observing System) network at The network also allows access to the meteorological measurements made on those rigs, so we’re not without our third-party data in any area of the experiment.

The food on board remains wonderful, and today’s lunch of calzones didn’t deviate from that script. The galley MVP of the past few days, though, is the pineapple upside-down cake (last night’s tiramisu was a strong second-place finisher). Thankfully, the size of the original cake was fairly large, so it had a good deal of staying power as a leftover. That is to say, when we’re just back from drifter construction/deployment and sitting down to watch the women’s archery gold medal game, we have the opportunity for a great mid-meal sweet.

Deployment of the final 67 drifters will begin at around 3:30 PM EDT (about an hour from the “now” I’m writing in). The exact shape and orientation of the node configuration may change a few times between now and then, but at the moment it is looking like a giant “L.” I have been assured that this configuration is for entirely scientific purposes and the fact that our deployments will soon spell out “L S S” north of the “Large Scale Survey” track is a complete coincidence. Still, I can’t help but shake the feeling that the powers that be aboard the Walton Smith are using the Gulf of Mexico as a giant Ouija board to give Ed Ryan nightmares (Ed is the scientist at RSMAS who has been collecting the SPOT satellite data). In any case, I’d better get going before they find me.

Nathan Laxague signing off (somewhere between pondering an absurd conspiracy and coating himself with 45 SPF sunscreen).

Day 13: GLAD Expedition – bit of a blur

I’ll be honest- I don’t like to take shortcuts, but today was a bit of a blur. Maybe it’s because I’m trying to recall events that began 14 hours prior to my writing this. I’ll start simple: breakfast was as it always has been: fresh fruit (!), eggs, and breakfast pastry with some kind of squeezed citrus juice. With that out of the way, we continued to prepare for construction of the remaining 90 drifters. Last night saw the first 27 finished and hung on racks for their triangular deployment (referenced in the issue corresponding to Day 12 of the “Daily CARTHEan”).

Said deployment finished this evening around 6:30 PM. The inter-drifter distance was shrunk from previous iterations and the inter-node distance was augmented considerably. This resulted in a deployment operation with long transits in very nice conditions (if you discount the menacing clouds and associated weather that nearly de-railed the drop before a drifter had hit the water). I can say that I enjoyed my job today on the water as much as one can without getting a stern talking to or being arrested.

The night-time task has been to finish half-construction on the 67 drifters that will be deployed Tuesday for our cyclone hunt. As of 10:30 EDT, we are done. The trip is definitely in its home stretch, and it’ll feel quite strange come Tuesday night when we’ve bid farewell to our last little baby.

Nathan Laxague signing off (somewhere between “Margaritaville” and “Lola” on the construction party playlist).

Day 12: GLAD Expedition – Deja vu all over again

It’s like deja vu all over again…

Morning brought Gulfport, MS. Gulfport, MS brought visitors to the ship. Today’s gaggle of visitors was made up of scientists and representatives from the NRL (Naval Research Lab). After a brief tour/presentation much in the mold of last week’s version, we were off to Historic Gulfport. Same restaurant, different table (the oysters were too good to pass up). In the meantime, the ship was refueled, re-stocked, and re-organized. For those curious about the workings of commercial ports, our science staff donned reflective vests and were escorted across 1000 feet of concrete lot by T.W.I.C. (Transportation Workers Identification Credential) card-holding crewmembers. Protocol was upheld and the Chiquita boat remains unmolested.

Naval Research Laboratory’s ocean modeling chiefs Gregg Jacobs (2nd from right) and Pat Hogan (in between Gregg and Tamay) leaving R/V Walton Smith happy after compromise solution was reached for GLAD’s next target areas. (Photo by: Tamay Ozgokmen)

As of 5:30 PM local time, the Walton Smith is beginning the haul out of Gulfport’s excessively long channel (you might be able to see the thing from space). We are on our way back to the De Soto Canyon, where the powers that be have planned our third deployment to take place. In a change from the original, three-S deployment schedule, however, the CARTHE bigwigs have decided to add a fourth drifter launch. The remaining 90+ drifters will be split between drop #3 (three sets of three sets of three sets of drifters, or a 27-strong triangular, quasi-fractal node) and a cyclone-chasing deployment southwest of our current location. This is where the importance of the LSS (large scale survey) comes into focus: deployment plans were changed on the fly in an effort to capture and map features very recently detected. The 63+ drifters left over after tomorrow’s operation will be cast directly off the Walton Smith on a long, slicing ship trajectory that takes us across the cyclone in question. The hope: by judiciously spreading out our remaining resources we will be able to paint a more complete picture of the physical transport processes at play in this stretch of the Gulf. Sounds good to me (I just drop the things in the water).

Modified sampling plan of “triangle fractal”.

For the portion of this blog’s readership that has been following the UDM saga, recent developments have made the sensor’s status (in scientist-ese) inconclusive. That means it’s probably definitely not an error with the code and certainly maybe an issue with the electronic connections. I think.

Nathan Laxague signing off (somewhere between channel marker seven and watching some Olympic volleyball game).

Day 11: GLAD Expedition – Hyperbolic Points

July the 27th has been a bit of a lull in the normal course of GLAD events. It was to be expected, of course- our current ship trajectory has us heading towards Gulfport for a second refueling/restocking. Anyway, much of the day has been spent surveying, organizing data, and (for me) sorting out a data collection issue with the UDM (our old friend the ultrasonic distance meter). Nothing to worry about, dear readers- just a hiccup that requires a little elbow grease and a few motes of patience.

Photo by: Tamay Ozgokmen

One of today’s tasks has been to periodically deploy drifters (outside the 270 allocated for S-deployments) along our path north of the De Soto Canyon. This puts them in shore-based HF (high frequency) radar range, so we can peek at surface currents remotely while our Lagrangian drifters are floating through them.

The northeastern tip of the De Soto Canyon is a happenin’ place right now- the ship’s onboard ADCP (acoustic doppler current profiler- harnessing the power of SOUND to measure FLOW SPEED, among numerous other things) put the currents at one portion of the surface at around 75 cm/s. For those among this blog’s readership who don’t swim with meter-sticks in hand, that is a rather energetic flow speed.

It is the hope of many modelers working in CARTHE that we find several so-called ‘hyperbolic’ points, where drifters initially placed close together will diverge on completely different paths. I don’t need to get too much into how this is of interest to a research consortium studying the transport of ocean-borne oil. These points would make GPS-laden drifter recovery a chore two days after launch- forget tracking down oil two months after a disaster. Those are the kind of features that we’re on the lookout for in this patch of ocean. The peaceful facade of calm waters and gentle waves belies a pattern of currents that is both chaotic and angry. CARTHE director (and fellow Walton Smith resident) Dr. Tamay Ozgokmen recently noted that the ocean models that sought to forecast oil transport in the wake of the Deepwater Horizon accident were “very, very wrong … day in and day out.” That’s a pretty unequivocal condemnation. It’s also the reason we’re out here.

Nathan Laxague signing off (somewhere between writing code in a language he doesn’t understand and screaming at another sensor).

Day 10: GLAD Expedition – Another day, Another drifter

Another day, another drifter deployment.

This morning contained the entirety of our “S2” deployment. Three hours of ripping around our drop site left us with a total of 214 transmitting GLAD units in the water. For those of you don’t track this kind of thing on your own, this means that the Grand Lagrangian Deployment is now the largest (by number of drifters) drifter deployment experiment, well, ever. And we’ve still got about 100 more to go. So, in lieu of celebratory champagne (UNOLS policy forbids booze on their vessels), I expect a few “attaboy” e-mails from some of the other members of CARTHE. Take what you can get, right?

At the time of my writing this, our winch-operated CTD is in the midst of a 1500 meter cast (yes- it’s one of THOSE days). In truth, our device is less of a CTD and more of a CTDFDO (conductivity, temperature, depth, fluorescence, and dissolved oxygen). It’s fancy. Characterizing the physical processes in play by acquiring these vertical profiles from the water column is important. It will certainly be of interest as we begin to reconcile surface current data from the drifters with other measured physical quantities.

R/V Walton Smith

The final deployment (“S3”) will occur either Monday or Tuesday, so we’ve got some time between now and then to survey, organize, and construct. The scratches and splinter wounds perpetrated by the drifters during construction and movement will have healed by then. I guess this is what having a cat is like- minus the joys of cleaning up random dabs of poo or the animals’ characteristically conditional love.

On the more mundane side of things, I took advantage of this afternoon by doing my laundry. That is all.

Nathan Laxague signing off (somewhere between moving his damp clothes to the dryer and finagling with threateningly large data sets).

Day 9: GLAD Expedition – Construction PARTY!

As of 4:15 PM Eastern Daylight time, our construction for drifter deployment S2 had been completed. Well, half-completed. One half of the sails were left off to allow for compact storage and to decrease damage to drifters while the ship is in transit. The bulk of the legwork is done and our precious fiberglass is no longer in peril of snapping due to high winds or the ship’s motion. Anyway, the second construction party proceeded much like its predecessor: stations were set up in the dry lab for assembling sails and attaching floats before the empty bodies were fitted with a GPS device and sealed.

The musical accompaniment to our building efforts came from a hodgepodge playlist made of musical donations from the other scientists. Gluing and fitting was done to a musical slurry containing everything from Jack Johnson (not mine) to Tom Waits (definitely mine) tunes. Now, at the time of my writing (a little over two hours past completion of drifter construction), we are fairly far into a pre-S2 CTD survey.

Augmenting our pre-deployment data collection efforts is the new sensor that Dr. Derek Bogucki (a guest star who first made his appearance in Episode 7) brought aboard. The device uses a tightly-packed horizontal band of lasers and sensors to measure miniscule variations in seawater refractive index (here a function of local temperature).

Dr. Bogucki’s sub-surface turbulence sensor.

The objective: to quickly sample turbulent structures of varying length scales. Of course, our camera array on the 01 deck will be running concurrently with the turbulence sensor to bolster the base of information we have for these target, small-scale processes. Tomorrow we deploy the fruits of today’s labor. Tonight, we eat. I’ve been told it’s something Italian that involves flank steak. Needless to say, I’d better stop writing before this blog becomes a puff piece for the food on board the Walton Smith.

Nathan Laxague signing off (somewhere between shutting off the polarimetric camera and eating pignola).

Day 8: GLAD Expedition – Codename “Wild Goose Chase”

The S1 recovery operation (codenamed “Wild Goose Chase” in yesterday’s post) is almost done. Informal (and modest) estimations had us finding around half of the originally released 90 drifters. At the time of my writing this (seven hours into this operation) 77 of the 90 initially released have been recovered. I would not be shocked if we were able to get all 90 that we need to get, so this is a rather exciting turn of events.

My morning and early afternoon was spent on the small boat I.B.I.S. I have a sneaking suspicion that I.B.I.S is an acronym, but my standards of journalistic integrity prevent me from airing errant hunches.

In any case, recovery has been much like deployment, except that the drifters are now arranged in a [classified for scientific purposes] manner rather than in the neat little nodes. Once the white drifter bodies are recovered, the GT-31 boxes are snipped (along with the flashing LEDs), and the bodies are cast into the drink again. One really neat part of the recovery process is seeing the multitudes of fish that crowd each drifter. They ranged in size from fingernail-scale crabs to meal-sized mahi mahi. And they were fearless. We were able to get some cool footage of our new animal friends, so look for that to be added to the CARTHE Facebook page in the near-ish future.

They say that the sun takes it out of you. Rather than argue with ancient wisdom, I’ll let it be and head to dinner. Tomorrow the cogs of our drifter-manufacturing machine will be turned by our able hands (and hopefully some background music). Who needs deck space, anyways?

Nathan Laxague signing off (somewhere between drifter body 82 and 84).