In search of the ocean's currents
In a one-of-a-kind concerted effort, oceanographers from Germany and the US are making the ocean's vortex flows visible. To do so, they've taken to water and sky - and in a zeppelin, no less.
A quiet trip over still waters
At first glance, it appears as if this zeppelin, deployed by the Helmholtz-Zentrum Geesthacht Center for Materials and Coastal Research, is floating merrily above a body of homogenous, flat water. In truth, the waters below the airship are anything but calm.
Like gears in a clock
The zeppelin's been underway for a week now, and here are just some of the colorful results: a spiral vortex with a diameter of three kilometers (1.9 miles) just south of the Danish island Bornholm. The twisting currents the researchers are examining have given the expedition its name: the Clockwork Ocean expedition. The numerous vortices affect each other like the gears of clock.
Inside the zeppelin
The expedition's being led by Burkard Baschek, who heads the "operational systems" unit at the coastal research institute. Here, he and a colleague examine pictures from a special camera attached to the zeppelin's underbelly. The pictures are highly sensitive infrared and thermal images, allowing the investigators to see small changes in temperature.
Wingmen
The zeppelin's accompanied by a motor-propelled glider plane. Pilot Nicolas Huhn (L) and Martin Theis (R) are from the Aachen University of Applied Sciences in western Germany. The glider's task is to take infrared images of the water prior to the zeppelin's take-off.
On the hunt
The glider notes any vortices down below and reports them to the zeppelin and the three research ships in the area of research. The latter are responsible for highly detailed measurements of the waters in question...
Support from below
Two out of three ships belong to the Helmholtz-Institut Geesthacht. The research ship Ludwig Prandl is featured in the distance, while nearer to the camera a small boat, Eddy, that can handle the high seas.
No success without cooperation
Such a complex research mission can only be accomplished through collective action. That's why the Leibniz-Institute also shipped its research ship, Elisabeth Mann Borgese, on the expedition as well.
Sensors delivering data
In addition to the cameras and photographs from the zeppelin, there are numerous other sources of data as well. Here, a researcher prepares a buoy, which the, via satellite, delivers info on the currents, the water temperature.
'Fish' on a line
The "fish" being dragged behind the boat here isn't a fish it all. It's a dish full of sensors that - among other things - measure the water's thickness, oxygen levels and concentration of algae.
Big things come in small boats
Eddy, the smallest boat, is equipped to the teeth with an arsenal of sensors and instruments. One of them is an acoustic Doppler current profile (ADCP). It works a bit like the rain radars that weather forecasters use to predict weather patterns. But rather than radar, sonar's used instead. That allows researchers to tell the absolute speed of the currents over the ground.
The sensor chain
Here, researchers drop a chain of sensors into the water. They'll be trailed behind Eddy the faithful speedboat. Attached to the chain are ten depth sensors as well as sensors for salt, oxygen and chlorophyll. A paper-airplane-shaped depressor at the bottom of the chain keeps these instruments at 40 meters' depth (131 feet) even at speeds of 10 knots.
One week left
In a picture gallery like this one we're only able to cover a fraction of the instruments currently in use on the Clockwork Ocean expedition. The ships have cabinets full of sensors, and there are also fully autonomous "swarm" robots underwater. They'll stay there until 4 July, when oceanographers will retrieve them, land the zeppelin and begin the "dry" phase: analyzing the data.