Mooring operations complete!

Just a quick update to let you all know that we successfully recovered the rest of our mooring equipment and have started downloading the data from all the instruments. We steamed northwards overnight to start a north to south transect of the Scotia Sea, including both CTD and VMP work. We had a showery day today, though the upside of that was a great double rainbow, captured below by Uriel.

Scientist Profile: Dhruv Balwada

Today we spoke to Dhruv, who has spent much of the cruise busily helping the tracer team with their work in the container.

Where are you are studying?

I am a second year PhD student at Florida State University working with Kevin Speer. My current research is related to understanding how the numerous eddies and jets in the Antarctic Circumpolar Current (ACC) control the mixing.

What is your involvement is with the DIMES project?

My involvement with the DIMES project has been related to processing the RAFOS float trajectories. These density layer following floats were deployed along with a tracer at key sites in the ACC to get a picture of the effect of eddies and jets. Each float has a story to tell about where it went, how fast it went, what kind of events it witnessed during its time in the water, did it get stuck in situations out of which it was hard to get out and a lot more. Each story is very interesting in itself, but we need to combine all the stories together and then an image starts to emerge. This image gives us an idea about the mixing rates, the scales of flow, where the dominant patches of energy are located, what eddies do to fluid particles and a lot more. In a few words, I do processing, analysis and statistics on Lagrangian (flow-following) particles to get estimates of mixing regimes at play in the region.

What do you personally want to get out of this cruise?

For me this cruise is a learning experience about going to sea and how research cruises operate. It also gives me to opportunity to see first hand how the data are collected for both the tracer and microstructure components of DIMES. I have been working with the tracer team and have gained experience in sampling and analyzing sea water for the tracer and a few other CFCs.

What do you enjoy about going to sea?

I enjoy the rocking motion of the ship, it’s like being on a never ending amusement park ride! It also gives us oceanographers the opportunity to get closer to our element.

Making 'moor' progress...

Under clear skies and with light winds, we recovered four of our six moorings today. These moorings, which contain instruments at a variety of different depth levels measuring current speed, pressure, temperature and salinity, were deployed on the UK2 DIMES Cruise in December 2010 and have collected 14 months of data. The aim of the experiment is to investigate mixing and internal wave breaking processes over a sea-floor rise close to the Subantarctic Front.

Mooring operations on the aft deck

Disassembling and storing buoyancy spheres

Mick and Steve at work with the crane

A typical mooring recovery involves ranging the mooring to find out its exact location, then acoustically releasing the instruments and mooring wire from its anchor on the seabed. The mooring then drifts to the surface and the ship is positioned to allow recovery on the aft deck. The mooring line is then slowly hauled onboard ship and the buoyancy and instruments removed from it.

To complement this work, we aim to complete a VMP and tow-yo CTD overnight tonight, before recovering the final two moorings tomorrow. Many thanks to Uriel for the recovery photos.

How does the ship work? It’s Engine-ious…

Control room

Ship's main engines

After we had finished our CTD operations this morning, a group of scientists were shown around the engine room by Third Engineer Bill. We spent an hour clambering around amongst the engines and generators and were even shown what happens to all the ship’s sewage! RRS James Cook has four engines, generating the same amount of power as used by the Falkland Islands! Fuel consumption onboard generally averages around 10 tonnes per day, though this increases to 24 tonnes at maximum speed (16 knots). The ship can make 11 m³ of fresh water per day and the vessel has four thrusters for maneuverability and stability. The ship can also move up to 6 knots sideways!

Many thanks to Bill for the excellent tour. Uriel and Katy have kindly shared some photos.

The sewage system and test toilet!

Crawling around ...

Alex cooling off by the air vent

Ben and Katy trying out the tools for size...

Tropical Questions!

After the work had finished last night many of the scientists and crew spent a few hours in the ship’s bar doing a pub quiz set by our resident quizmaster Carl. The theme for the party was tropical, so it was grass skirts, snorkels and palm trees all round! The eventual winners were “Quizteama Aguilera”, comprising John, Graham, Steve and Wally. Many thanks to Heather, Katy, Carl and the galley for organising a great evening, and to Andy for the photographs.

Steve and Ben in tropical attire

Carl and Marie-Jose

Neill in arboreal headgear, with Gabriella

Heads down for "The Beach Babes"

We have just arrived on station to the north of Burdwood Bank and are doing the first of our CTDs here. Unfortunately, there is currently thick fog in the work area, postponing VMP operations at the moment.

AARDVARK: isn’t that the first word in the dictionary?

The word may appear on page 1 of any English Dictionary, but to us the AARDVARK programme instead refers to a series of float deployments that forms an integral part of the DIMES project. The aim of AARDVARK is to identify places in the ocean where two or more floats deployed in a similar location experience a very rapid, exponential-type separation over time. This can give us important information about ocean mixing. The floats themselves drift on the surface, but have a sock (or drogue) which hangs 15 m below sea level, meaning the float moves with the near-surface currents (and not the wind). The position of the floats over time is tracked by satellite.

Last night, we deployed eight of these drifters as we steamed westwards towards the north side of Burdwood Bank. In a slight change to our schedule, we are now aiming to do a short CTD and VMP survey of this region overnight tonight before steaming southwards to recover the moorings on Monday.

Paul and Steve deploying a drifter last night

Four drifters ready for deployment on deck.

I would steam 500 miles..

Well, 502 to be precise, to start the recovery of a set of moorings that we deployed last year. I’ll tell you more about that in the next couple of days, but along our steam we will also be deploying eight surface drifters that track the near-surface currents and identify different mixing pathways. We’ll try and get some pictures of the deployment operations tomorrow!

Best wishes to Steve who celebrates his birthday today

Steve receiving one of Stanley's finest pieces of penguin parphernalia!