A song of ice and fiber

Sandia embarks on Arctic seafloor data project using new underwater technique

DOE/SANDIA NATIONAL LABORATORIES

Science Business Announcement

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IMAGE: A RARE, PEACEFUL SUNRISE AT OLIKTOK POINT DURING THE FIRST WEEK OF FEBRUARY WHEN SANDIA NATIONAL LABORATORIES RESEARCHERS BEGAN COLLECTING THE FIRST-EVER DATASET FROM THE ARCTIC SEAFLOOR USING DISTRIBUTED ACOUSTIC… view more CREDIT: PHOTO BY KYLE JONES, SANDIA NATIONAL LABORATORIES

ALBUQUERQUE, N.M. — Sandia National Laboratories researchers are beginning to analyze the first seafloor dataset from under Arctic sea ice using a novel method. They were able to capture ice quakes and transportation activities on the North Slope of Alaska while also monitoring for other climate signals and marine life.

The team, led by Sandia geophysicist Rob Abbott, connected an iDAS, a distributed acoustic sensing interrogator system manufactured by Silixa, to an existing fiber optic cable owned by Quintillion, an Alaska-based telecommunications company. The cable reaches the seafloor from Oliktok Point. For seven days, 24 hours a day, cable vibrations were captured and recorded, helping researchers better understand what natural and human-caused activity takes place within the data-starved ocean.

This is the first time a distributed acoustic sensing interrogator system had been used to capture data on the seafloor of the Arctic or Antarctic oceans, and the team sees many advantages for future use.

“This is a first-of-its-kind data collect, and as far as what national laboratories do, this is exactly the type of high-risk, high-reward research that could make a huge difference in how we’re able to monitor the Arctic Ocean,” said Sandia manager Kyle Jones. “This really is on the cutting edge of seismology and geophysics, along with climate change and other disciplines.”

The team is expecting to record climate signals like the timing and distribution of sea ice breakup, ocean wave height, sea ice thickness, fault zones and storm severity. Shipping, whale songs and breaching can also be recorded. This new way of monitoring holds the potential to persistently capture a wide variety of Arctic phenomena in a cost-effective and safe manner so that scientists can better understand the effects of climate change on this fragile environment, Abbott said.

The interrogator looks like an electronic box that can be attached to the fiber optic cable on land, and it uses a laser to send thousands of short pulses of light along the cable every second. A small proportion of that light is reflected back — or backscattered — along the cable as the seafloor it’s attached to moves due to earth, sea ice, ocean current and animal activities. The backscattered light enables the interrogator to detect, monitor and track events along the fiber, and data is stored on hard drives.

“Quintillion’s fiber optic cable is in a favorable place on the North Slope of Alaska,” Abbott said. “This technology works for this project for several reasons. We are not sending a boat out to plant monitors; we’re not traipsing over the sea ice trying to install sensors. This cable will exist for decades and we can take good data on it. It’s a very safe way of taking this measurement in a hazardous environment.”

Funded by the Laboratory Directed Research and Development program, this was the first of eight week-long data collections that will happen over the next two years during the project. The team will visit Alaska in each of the four Arctic seasons defined as ice-bound, ice-free, freezing and thawing. A third year will be spent further analyzing data.

Abbott said results will be communicated with the broader scientific community and will be provided to the climate modeling community for inclusion in algorithms. Additionally, the team hopes the results of the project will show the need for persistent distributed acoustic sensing monitoring in the Arctic.

“We’d like to provide data to high-fidelity climate models and raw data analysis,” Abbott said. “I’m also hoping to conduct a direct measurement of sea ice thickness, which is currently difficult. Right now, you need an airplane flying over or you need to go out on the ice. That can be very dangerous and expensive, and you can only do it once or twice a year. Using a fiber optic cable, the distributed acoustic sensing system could be out there 24/7/365 and you could potentially take a sea ice thickness measurement once per day.”Encouraging data captured in first 168 hours

Sandia researchers are just starting to analyze the first 168 hours of data collected in February, and they are encouraged by what they see, Abbott said.

“We see things that are indicative of ice quakes. We see events as far out as 33 kilometers in the ocean where there should be no anthropogenic activity,” he said, referring to the first two hours of data he’d looked at. “We’re certainly seeing a natural event of some sort. It could be an ice quake, or it could be a micro-seismic event in the ground like an earthquake. We’re not sure yet.”

Closer to shore, Abbott said the team most likely recorded production and reinjection wells recycling wastewater and frequencies that are indicative of ocean tides and currents. One surprising result was the system picking up frequencies of a low-flying hover craft.

The interrogator can record events at a spatial density of three to four orders-of-magnitude greater than traditional hydrophone or ocean bottom seismometer deployments, Abbott said.

“In this first data collect, we weren’t expecting to see a lot of currents and ice quakes because there was stable ice cover over the entire area, and yet we do see some of those things, which is exciting,” Abbott said.

Abbott said he’s looking forward to capturing data on whales and seals during the migrating season. The Arctic is home to bowhead and beluga whales, each having individual songs. The system should be able to record these songs in the same manner as recording earthquakes because vibrations in the ocean are transmitted to the earth, which is then transmitted to the cable. With whales, a characteristic pattern develops as the song changes pitch.

“It’s called gliding, where over time, the frequencies start out low and go high and back down,” Abbott said. “Frequencies like that are characteristic of biological sources and are easily discriminated from other sources, such as earthquakes. Whales often sing for over 30 minutes with individual repeated notes that last a few seconds long that glide up and down.”North Slope weather added intensity to experiment’s critical first week

The expected but fierce North Slope climate was a challenge. In February, the area is dark about 18 hours of the day and because snow blows much of the time and roads aren’t well marked, everything continues to look new, Abbott said. The team was also dealing with bitter cold, and while they were prepared, temperatures were about 10 degrees colder than expected, at one point dropping to minus 45 Fahrenheit (minus 77 including windchill). Even the people who work there for a living shut down all outdoor activities, Abbott said.

“The American Arctic is formidable, 30 degrees below zero being a common occurrence in the winter months,” said Michael McHale, Quintillion’s chief revenue officer. “Much of the region is tundra and difficult to traverse in the best of weather. Working here requires significant experience and hard-won expertise. The engineering implications are enormous. Most networks and satellite ground stations do not operate in regions where they need to be able to tolerate 70 degrees below zero.”

Due to harsh conditions, Quintillion’s fiber optic cable is double-armored with copper and steel sheathing to protect against cutting, crushing or abrasion damage, McHale said.

“All of the company’s network components, including the cabling, are engineered to withstand the extreme Arctic environment and protect against network outages,” he added. “The subsea portions of the cable are primarily buried below the seabed.”Nerves lasted throughout week as successful data collection was uncertain

The day after the team arrived, researchers met at the Quintillion cable landing facility where the distributed acoustic sensing system was installed with the help of the company. A team member from Silixa, the company Sandia purchased the distributed acoustic sensing system from, was also there to assist.

Sandia researchers were able to utilize about 30 miles of the subsea fiber optic cabling, McHale said, and setup went smoothly. He added that the project has been a great experience so far.

“The opportunity to work with some of the most knowledgeable geophysicists and data scientists in the country is exciting and an honor,” he said. “Supporting the work of the scientific community has long been a goal of Quintillion’s. Accomplishing that goal with a client as highly regarded as Sandia Labs exceeded our expectations.”

During the first few days of the initial collection, there was anticipated nervousness among the team because this was something that hadn’t been done before. While Abbott has used fiber optic cables to record explosions for Sandia, he hadn’t used them on a seabed nor for something this large.

The interrogator gathers 2 gigabytes of information per minute, and because it’s coming in so fast, it’s difficult to know whether the data is good, Abbott said. After three or four days, the team had indications that the system was working well, and it took the entire week before they felt confident about the experiment.

“What I’m excited for is we see a lot of interesting phenomena in this data collection, which will probably be the quietest dataset with the fewest amount of ice quakes or wave action,” Abbott said. “Once we start to see the ice break up and icebergs crashing into each other in other seasons when there’s no ice up there at all, we’ll see things better like tides, currents and storms.”

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Ron Long
April 11, 2021 3:38 am

We apparently have to wait to see how much actual data this project develops. However, the scientific staff from Sandia National Laboratories is excellent, maybe the best collection in the world. They were the developers of the President Reagan “Star Wars” program, with directed plasma beams one of the goals. About 30 years ago they began to mix in public-interest and commercial studies, and the exploration research group I was managing contracted with an expert from Sandia. His physics explanation of the reflectance of photons from our target identification goals was amazing and useful.

Oldseadog
April 11, 2021 4:38 am

….. “”low-flying” hover craft.
Is there any other kind?

Clyde Spencer
Reply to  Oldseadog
April 11, 2021 9:43 am

Former “high-flying” hover craft. 🙂

ATheoK
Reply to  Oldseadog
April 11, 2021 9:45 am

I don’t think I’ve ever seen a hovercraft that did more than float just above the ocean’s surface.
Nor have I heard of a quiet hovercraft. Detecting one should not be a surprise.

Prsy
April 11, 2021 4:48 am

I wonder if it’ll pick up Russian subs…

commieBob
Reply to  Prsy
April 11, 2021 5:33 am

Soviet submarines used to be unbelievably noisy. link They fixed that. Still, a submarine should create a pressure wave as it travels beneath the surface. I’m guessing it could be detected by impedance changes in the fiber optic cable. I’m also guessing that the pressure wave from a submerged vessel would be somewhat different than that of a surface vessel if only because it would be generated closer to the cable.

rah
Reply to  commieBob
April 11, 2021 8:20 am

Actually we, that being the US, helped fix that by allowing the sound dampening technology, including the propeller designs, developed for our own subs to be distributed through various subcontracting international businesses. So China and Russia ended up with that classified technology.

Scissor
Reply to  rah
April 11, 2021 9:48 am

C’mon man, you don’t want to make it difficult for enemy spies do you?

DMacKenzie
Reply to  Prsy
April 11, 2021 5:59 am

Is there a “donate” button on Sandia’s website ? If not, it is logical that the project has funding from unnamed sources for purposes auxiliary to the published ones. “Submarines” is a good answer, like Argo floaties, and programmed/data manipulated to give results that ensure more of them are required……at least that’s my conspiracy theory of the day….

Last edited 3 months ago by DMacKenzie
old engineer
Reply to  Prsy
April 11, 2021 3:23 pm

I’m sure they hope to. Why do you think researchers from Albuquerque are up in the Artic in the middle of winter? So they can hear whales sing next summer? Sure they are.

Note also that the funding is coming from a “Laboratory Directed Research and Development program” I read that as funded with money from the lab annual budget. That type of program is generally used as a teaser to get a really big project funded by a government department like DOD.

Last edited 3 months ago by old engineer
commieBob
April 11, 2021 4:55 am

There is a device called a time domain reflectometer (TDR). What the Sandia folks are doing sounds like that.

If the impedance of a cable or fiber changes because it has been crushed by a rock when a trench was back filled, you use the TDR to locate exactly where the fault exists.

Anything that physically moves a cable or fiber changes its impedance slightly. You can tell where along the fiber the disturbance exists.

Suppose you wanted to bug a room and you had access to a cable that ran through one of its walls. In theory you could detect sounds coming from any point you want along the cable run. My fevered brain is reeling from the implications.

Reply to  commieBob
April 11, 2021 5:06 am

Much space for speculation what the sources of sounds are.

commieBob
Reply to  Krishna Gans
April 11, 2021 6:27 am

Actually, that kind of activity is easy to detect from outside the house. No access to cables is required. Do you have a wifi router? link Do you have a power meter? link

mcswelll
Reply to  commieBob
April 11, 2021 1:25 pm

can’t you also bounce a laser beam off a window?

Lee Scott
Reply to  commieBob
April 11, 2021 7:59 am

I suspect the CIA is already well aware of the capabilities! And since it’s now available to the public, it’s probably old technology by now from a national security standpoint.

Roy Martin
Reply to  commieBob
April 11, 2021 1:52 pm

For fiber the instrument would be an Optical TDR (OTDR), that measures scattered or reflected light rather than impedance, but the principle is the same.
https://en.wikipedia.org/wiki/Optical_time-domain_reflectometer.

A long time ago I used a WAVETEK LANTech 100 for just those purposes.

rbabcock
April 11, 2021 6:37 am

It will be interesting how good they will be in interpreting the data. Sounds travel pretty far under water and recognizing the exact source of each and every “wave” hitting the cable might be a little iffy. Sharp sounds close by might be easy by the intensity and duration reaching the cable but if you are measuring “pressure” reaching the receptor and you have a number of sounds emanating from one direction at various distances, the waves may spike or cancel each out depending on the interference pattern.

Maybe it is like passive sonar where they get rid of the noise and concentrate on specific sounds.

Lee Scott
Reply to  rbabcock
April 11, 2021 8:07 am

This is pure speculation, but if you know the speed of light through the cable, you should be able to isolate sounds by filtering the back scatter, measuring the time delay from the pulse to the return, the same way radar works.

Theoretically, you could isolate data from any section of the cable by only concentrating on back scatter with an exact time delay corresponding to its distance from the pulse generator.

I could see this being huge for monitoring earthquake fault lines. One cable running the length of the San Andreas fault, for example, could pinpoint every micro-quake almost instantly.

Last edited 3 months ago by Lee Scott
Bruce Cobb
April 11, 2021 6:44 am

What we need to know is if the Arctic is screaming yet, or has stopped screaming, or maybe is just sobbing and weeping now.

Scissor
Reply to  Bruce Cobb
April 11, 2021 8:19 am

Mark Serreze and Jay Zwally disapprove of this message.

Sweet Old Bob
April 11, 2021 7:08 am

” ….takes place within the data-starved ocean. ….”

I don’t think the ocean is hungry …

😉

Carlo, Monte
Reply to  Sweet Old Bob
April 11, 2021 7:35 am

I groaned when reading this, obviously the product of an arty tech writer.

Scissor
Reply to  Sweet Old Bob
April 11, 2021 8:34 am

Too much salt in its diet.

Frank from NoVA
April 11, 2021 7:30 am

Will the “interrogator” be upgraded to the “inquisitor” at some point?
I’m all in favor of gathering physical evidence on how this mysterious planet of ours works, but how likely was it that there had to be a defense / intelligence / climate change hook in the proposal in order to get funding? Not being paranoid, just mindful that good data from radio sondes that refute the skill of GCMs has been piling up and ignored since IGY.

Joel O’Bryan
April 11, 2021 7:33 am

“Climate signals”
“data-starved oceans”
The fervent imagination of the climate religion faithful never ceases to amaze me.

Scissor
Reply to  Joel O’Bryan
April 11, 2021 8:37 am

Surprisingly, the fully hydrated Arctic Ocean experiences no problems with bladder control.

Curious George
April 11, 2021 7:36 am

The authors substituted the word “interrogator” for the original “intelligent”.
The iDAS is manufactured by Silixa, and Sandia applied it in an icy environment.

ATheoK
April 11, 2021 9:54 am

“Sandia researchers are just starting to analyze the first 168 hours of data collected in February, and they are encouraged by what they see, Abbott said.

“We see things that are indicative of ice quakes. We see events as far out as 33 kilometers in the ocean where there should be no anthropogenic activity,” he said, referring to the first two hours of data he’d looked at. “We’re certainly seeing a natural event of some sort. It could be an ice quake, or it could be a micro-seismic event in the ground like an earthquake. We’re not sure yet.”

Translated:
We’ve barely started.
We don’t know what things mean, yet. But we’re happy to presume.

The team is expecting to record climate signals like the timing and distribution of sea ice breakup, ocean wave height, sea ice thickness, fault zones and storm severity.”

Climate? A seasonal weather event is now climate?

“This really is on the cutting edge of seismology and geophysics, along with climate change and other disciplines.”

More climate claims?
Before this technology records a length of time suitable for climate considerations, this technology and equipment will be modified multiple times.

The Dark Lord
April 11, 2021 12:29 pm

measure the effects of climate change ??? but they can’t define climate change so what are they measuring ??? they can measure the weather (maybe) but nobody can clearly state what the changes to weather will be going from one climate to another … and thats because they can’t since going from cold to hot has the same weather are going from hot to cold … hot being ice free poles year round and cold, polar ice year round …

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