What Does A Melting Glacier Sound Like?
May 23, 2018 1:24 p.m.
What Does A Melting Glacier Sound Like?
Grant Deane, research oceanographer, Scripps Institution of Oceanography
Related Story: What Does A Melting Glacier Sound Like?
>> Climate scientists are working on a new way to monitor rising ocean levels. The sounds of glaciers melting. Researchers say they can track these noises to figure out how fast glaciers and icebergs are melting back into the sea. Midday addition Michael Lipkin spoke to oceanographer, grant Dean, but the new study.
>> Let's start with a sound recorded in Norway. This is a sound of an iceberg melting. I mostly hear the sound of rushing water. What you hear when you listen to this?
>> That's exactly what I hear to. It's the same thing that's making sound. With running water, you are creating bubbles. When a bubble is formed, it radiates a sound. It has musical qualities to. That's why Running Water sounds musical. It's because of the delightful sounds of these bubbles he made in the water. With the glacier ice, it is also bubbles. It is ancient atmosphere trapped in the ice that is transported to the sea over hundreds of years under great pressure. When that ice melts, it releases that gas back into the water makes a sound of bubbles.
>> These are underwater microphones? When you're out on a boat and you hear these glaciers, are you hearing the same rushing water even though the water is not moving I quickly?
>> The first time I heard this recording, I thought there was something wrong. It was a still day and it sounded like that.
>> Why even turned a sound to study sealevel rise? From what I understand, many people use satellite images to study how quickly glaciers are melting.
>> Yes, but there are other methods. People take photographs of them, they shine lasers at them and they put sticks in front of them with GPS systems. It is a very important question. We need to get a handle on it if we need to understand sealevel rise. The problem is, the glacier is not just melting, it is moving forward. The glacier ice itself is flowing forward. Then it is carving which takes the front of the glacier and moves it backwards. How do you figure out what melting is doing as opposed to flowing and carving? We think the sound can answer that.
>> How do you translate the noise of these bubbles to tell you how quickly or not the glaciers moving?
>> Well, you've asked the scientist one of his favorite questions. I can go on for a long time, but I won't. The concept is simple. Each bubble makes its own sound. The sound is characteristic of the bubbles in the ice. If we can figure out each individual bubble makes, when we measure all of them, we should be able to figure out how many of them there are. If we know how many there are in the eyes, then we can figure out how much ice has disappeared.
>> You can say we've listen to 5000 bubbles and that equals is volume of ice and this ecosystem of sealevel rise.
>> That's right. Is a team of us going up to the Arctic this summer, myself, and Dale Stokes. We'll come up and melt hundreds of blocks of glacier ice. We will photograph the bubbles and count them. Then we will listen to the sounds the ice makes as it melts to make that link between the mobile noise in the melting rate.
>> We were listening to a relative small piece of ice melting. Here's what it sounds like when in the tire glacier melts. -- When an entire glacier melts. That seems like an entire -- a lot of hissing to me. How do you sift through this type of noise when you gather it and take it back to the lab?
>> As you can tell, there may bubbles popping at the same time. We can't count the bubbles individually. The noise of them is arriving at the same time. So, we have to do some fancy physics and signal processing. We have to calculate the power spectrum of the noise. But, there is a link between that sound and the noise that is being produced. If you're at a cocktail party and you knew how loud each person worse, you may not be able to hear one person, but you would be able to figure out how many people are in the room, approximately.
>> This is a work in progress. You don't quite yet have that formula?
>> That is correct. In fact, we have almost enough information to do that for one glacier. But for this to be interesting and useful, it has to work for many glaciers. This year, will study at least 4 of them. In the future, we need to expend that study to more and more glaciers to make sure the technique translates.
>> What do you envision? Do you envision a future with her hundreds of microphone surrounding Greenland that your listing to all the time?
>> Yes, I want to surrender Greenland with underwater microphones. It is a cost-effective way to collect the data. You got and have 20-30 glaciers you are monitoring. You deploy the equipment and the recording technologies will develop. We can make an expensive long-term recordings of these processes. The complicated part is interpreting the data. If we can solve this problem, we will have a very convenient and inexpensive way of setting up long-term monitoring of Greenland. That is the big prize here. Can we monitor what's happening in Berlin for the next 10-20 years and figure out how quickly the glaciers are melting and how long we have until the ice Is destabilized perks
>> That was Brent Dean speaking with producer Michael Lipkin.