Underwater Gliders Help Scientists Better Understand Hurricanes

Nov 21, 2018

Credit UMass Dartmouth School of Marine Science and Technology https://bit.ly/2S4xBIq

Researchers at UMass Dartmouth recently retrieved an underwater glider they deployed to capture data that would help scientists better understand hurricanes.

The glider came back early than they'd hoped, but researchers were thrilled it had made a nearly 100-day trip from Martha's Vineyard to the edge of the continental shelf.

WCAI's Kathryn Eident talked with Wendell Brown, Chief Scientist and Professor at UMass Dartmouth’s School for Marine Science & Technology, to learn more about the glider—which is named Blue, in honor of the blue whale—and its mission.

Eident: The glider came back a little early, but you were still excited to get it back.

Brown: Right. And this was glider Blue's 10th mission. Most of the earlier flights were 23 days in duration. We had a glider Blue packed with lithium batteries this time and it had energy to burn.

Eident: And burn it did. So, it was out with the purpose of gathering some information to help researchers better understand hurricanes. Is a glider like Blue a common tool used to gather information like this?

Brown: The Navy has probably 200 gliders that they use for their operations, but from a research point of view, it's become a common practice. Whereas, we used to go out on ships ranging from $5,000rs a day to $20,000 a day, glider Blue does it autonomously. It radios back the data it's been recently collecting and by way of a constellation of satellites called Iridium.

Eident: I wanted to take a minute to explain exactly what a glider is; it's operating on its own, it's pre-programmed, and it's pretty unmistakable if someone were to come across it in the ocean.

Brown: It looks like a yellow torpedo about six feet long, but it has wings in order to traverse the ocean. It controls its buoyancy and so, on the surface that will suck in some water and make it heavier than the surrounding water, sink toward the bottom, but because it has wings, it slides, and then when it detects the bottom, it pushes that water out and makes it buoyant and it rises. And so, I like to describe the locomotion of an autonomous glider as saw-toothing its way through the ocean.

Eident: What specifically were you trying to understand with your glider on this most recent mission?

Brown: The National Hurricane Center predicts the trajectories of hurricanes pretty well, but they fall short in predicting the intensity of particular hurricanes when they make landfall. And that relates to being unsure of the amount of heat in the ocean over which the hurricane moves. Because of the real-time transmission of gliders, modelers are able to make their models more accurate.

I particularly focused on the distribution of the cold pool. It's a swath of remnant winter water stretching from Cape Cod to Cape Hatteras and it represents basically, habitat. And, it also represents a cooling potential of the surface waters were it to mix to the surface. Hurricanes do a lot of mixing.

Eident: And that cold water could potentially impact how big or how fierce a hurricane becomes, right?

Brown: Right.

Eident: Wendell Brown, thanks so much for talking with us about what Blue was out there doing. And good luck with future projects.

Brown: Thank you.