Tag Archives | gliders

Test Your Memory With “What in the World?”

Many years ago, when your trusty blog writer and photographer were little, we used to open up each new issue of National Geographic’s kids magazine and look for a feature called “What in the World?” It was a quiz game where they would show an extreme closeup of something rather ordinary—a pencil tip, or a junebug, or a flower petal—and the reader had to guess what it was.

We thought we’d play a game of “What in the World?” on the Project CONVERGE blog. Let’s see how good your memories are: Each of the first six photos in the slideshow is a closeup of one of the photos that has already appeared on the blog. As you look at each one, try to remember where you’ve seen it before, and guess which post it was in. Then keep clicking—we’ll show you the full photos in the second half of the slideshow.

Are you ready? Click through and see how many photos you can identify:

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To see the photos in their original context, see the following posts. How many did you get right?

Orange Islands: Listening for Echoes of Krill
Candycane Mirrorball: This Is Life at 64 Degrees South
Urban Planning: How Gliders Work: A Look Inside the Blue Hen
Brush Strokes: Big and Bad, or Just Misunderstood? Meet the Southern Giant-Petrel
Drawn by a Ruler? Here Comes the Neighborhood
Black and White and Slightly Pink: Sights and Smells of Summer in an Adelie Penguin Colony

How Gliders Work: A Look Inside the Blue Hen

Earlier this week the glider team pulled in the University of Delaware’s glider, nicknamed the “Blue Hen,” from the ocean. They needed to change its batteries and download one of the instrument’s data. But they didn’t want to miss what was happening out at sea, so they pulled what they call a “Nascar turnaround,” working like a pit crew to get the work done overnight.

It gave us an opportunity to look at the inside of a glider and explore how these complicated robots manage to go where they’re told and collect the data we need, practically by themselves.

To fly, a glider needs a few basic abilities: it needs to be able to control its buoyancy so that it can either sink or rise; it needs to know where it is and where it’s going; it needs to be able to call home for new instructions; and it needs to be able to collect data. And it has to do all this with only a small allowance of space, weight, and battery power. Click through the slideshow to see how gliders manage it:

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ironcrossThe stream of data that comes back from the gliders every hour or so is what allows the CONVERGE team to be adaptive in their sampling. With a research ship or an instrument fixed on the seafloor, it’s difficult to change your plans as you get more information. But changing a glider’s plans is as simple as uploading a new instruction file.

Over the last couple of weeks the team has settled on a sampling plan they’re calling the “iron cross.” Each of the three gliders takes a different part of the cross (see the map), and together they reveal what the waters of the Palmer Deep are doing. The Blue Hen (blue on the map) flies to the center of the cross and just goes up and down in the same spot. The glider from the University of Alaska, Fairbanks (green), flies a straight line along the length of the Palmer Deep canyon. The Rutgers RU05 glider (red), flies across the canyon.

RU05 goes at right angles to the Alaska glider, and those two gliders cross at the spot where the Blue Hen is working. Altogether, this gives the scientists a way to separate out ways the water conditions could changing.

temperature profiles from a glider at Palmer Station, AntarcticaHere’s an example of the data they’re collecting, and why it helps to have data from more than one glider. This graph shows one round trip of the Alaska glider from the northeast end of its route, down to the southwest end, and back. The dashed line shows where the glider turned around—the two parts are different lengths because it took longer to fly out to the dashed line than to fly back. That’s because it was fighting the current in the left section of the graph; then it turned around and rode with the current.

The graph shows the temperature of the water as the glider flew up and down on its way. Do you see any differences? First of all, it’s interesting that the water is warmer at the surface and at the bottom (orange colors), and coldest in the middle (blue colors). This is because the sun has warmed the waters at the surface; the middle waters are still cold from winter; and the deepest waters represent a deep current that has brought in warmer water underneath it all. Layering of different water types is a very common feature in the ocean.

Now look at the left and right edges of the graph. Remember that the glider was doing a round trip, so these two parts of the graph represent the same patch of water at the northeast end of its route. On the left side compared to the right side, there’s less warm water at the surface and the colder middle water doesn’t extend as deep.

This is an interesting development, but it leaves the scientists with a problem: did the water change in temperature between the glider’s first pass and its second pass? Or did a current carry in different water, with a different temperature (as well as other characteristics) and push the original water out of the way? With only one glider taking measurements, it would be hard to figure this out. But with three gliders working the same stretch of water from different angles, they’re much more likely to be able to put together the answer.

Huge thanks to Laura Palmara for putting the map and data plot together for this post.

Robot Splashdown Over the Palmer Deep

At about 1:00 p.m. today, Dr. Josh Kohut was in an inflatable boat over an underwater canyon called the Palmer Deep. The wind was light, there was a little rain, and groups of gentoo penguins were swimming by the boat to see what we were up to. We were there to deploy four gliders—or, as Dr. Kohut put it with mild amazement, “Here we are in Antarctica, sitting in a zodiac and getting ready to throw some robots in the water.”

The team’s gliders are indeed torpedo-shaped robots that will “fly” through the water measuring basic aspects such as salinity, currents, and photosynthetic activity. They’ll stay out for weeks at a time, and they’ll check in every few hours to report what they’ve found and listen for further instructions. The CONVERGE team is using them to gather data about what’s going on under the surface, much as they’re using radar to study the surface water and find convergence zones.

“We think convergence zones are concentrating the food web [phytoplankton and krill],” said Dr. Matt Oliver of the University of Delaware. “So these gliders are going to go fly through those zones and find out if that’s true.” In scientific terms, the effect of convergence zones is one of the team’s hypotheses, and the gliders provide them with a way to do what scientists do: test their hypotheses.

Gliders are delicate, heavy, complicated machines—see what it takes to safely launch a glider in the slideshow below:
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glider positions, january 6All the time we were driving the zodiacs back to Palmer, the gliders were heading out along their programmed routes. By late evening, RU05 had split away from the others to follow its own route. The Alaska glider (AK03) and the University of Delaware’s Blue Hen were neck and neck, but Filipa Carvalho’s RU24 was out in front, owing to a slight difference in the way it was configured during testing.

The gliders will keep sending back data every few hours, and the CONVERGE team will get together each day to look at the results and decide on their next course of action. This almost instantaneous collection of data over such a wide area is something that has only become possible in the last 10 or 15 years. Check back over the next days and weeks to see how the team puts this potential to use.

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