• Skip to primary navigation
  • Skip to main content
  • Skip to primary sidebar
  • Skip to footer

Electrical Engineering News and Products

Electronics Engineering Resources, Articles, Forums, Tear Down Videos and Technical Electronics How-To's

  • Products / Components
    • Analog ICs
    • Battery Power
    • Connectors
    • Microcontrollers
    • Power Electronics
    • Sensors
    • Test and Measurement
    • Wire / Cable
  • Applications
    • 5G
    • Automotive/Transportation
    • EV Engineering
    • Industrial
    • IoT
    • Medical
    • Telecommunications
    • Wearables
    • Wireless
  • Learn
    • eBooks / Handbooks
    • EE Training Days
    • Tutorials
    • Learning Center
    • Tech Toolboxes
    • Webinars & Digital Events
  • Resources
    • White Papers
    • Design Guide Library
    • Digital Issues
    • Engineering Diversity & Inclusion
    • LEAP Awards
    • Podcasts
    • DesignFast
  • Videos
    • EE Videos and Interviews
    • Teardown Videos
  • EE Forums
    • EDABoard.com
    • Electro-Tech-Online.com
  • Bill’s Blogs
  • Advertise
  • Subscribe

Robotic Ocean Gliders Aid Study of Melting Polar Ice

November 25, 2014 By Jessica Stoller-Conrad, Caltech

The RRS James Clark Ross in front of an iceberg in the Weddell Sea. The iceberg, measuring roughly 25 km by 40 km was nearly the size of LA county. Ocean gliders used to measure heat transport at the Antarctic coastline were piloted around the iceberg as it floated along the coast. Image credit: UEA/Caltech The rapidly melting ice sheets on the coast of West Antarctica are a potential major contributor to rising ocean levels worldwide.

VIEW: Engineering Newswire 117: Electric Scooter Unfolds in a Second

Although warm water near the coast is thought to be the main factor causing the ice to melt, the process by which this water ends up near the cold continent is not well understood.

Using robotic ocean gliders, Caltech researchers have now found that swirling ocean eddies, similar to atmospheric storms, play an important role in transporting these warm waters to the Antarctic coast — a discovery that will help the scientific community determine how rapidly the ice is melting and, as a result, how quickly ocean levels will rise.

Their findings were published online on November 10 in the journal Nature Geoscience.

“When you have a melting slab of ice, it can either melt from above because the atmosphere is getting warmer or it can melt from below because the ocean is warm,” explains lead author Andrew Thompson, assistant professor of environmental science and engineering. “All of our evidence points to ocean warming as the most important factor affecting these ice shelves, so we wanted to understand the physics of how the heat gets there.”

Schematic diagram of the Antarctic coastline showing the continental shelf and slope (brown) and a glacier (white) terminating with a floating ice shelf. The colored section shows actual measurements of ocean temperature as collected from an ocean glider off the coast of the Antarctic Peninsula. The warm tongue of water that extends towards the ice shelf is driven by ocean eddies, swirling patches of warm and cold water. These are shown schematically by the warm (red) and cold (blue) arrows. Image credit: Andrew Thompson/Caltech and Lance Hayashida/Caltech Marketing & CommunicationsOrdinarily when oceanographers like Thompson want to investigate such questions, they use ships to lower instruments through the water or they collect ocean temperature data from above with satellites. These techniques are problematic in the Southern Ocean.

“Observationally, it’s a very hard place to get to with ships. Also, the warm water is not at the surface, making satellite observations ineffective,” he says.

Because the gliders are small — only about six feet long — and are very energy efficient, they can sample the ocean for much longer periods than large ships can. When the glider surfaces every few hours, it “calls” the researchers via a mobile phone–like device located on the tail. This communication allows the researchers to almost immediately access the information the glider has collected.

Like airborne gliders, the bullet-shaped ocean gliders have no propeller; instead they use batteries to power a pump that changes the glider’s buoyancy. When the pump pushes fluid into a compartment inside the glider, the glider becomes denser than seawater and less buoyant, thus causing it to sink. If the fluid is pumped instead into a bladder on the outside of the glider, the glider becomes less dense than seawater — and therefore more buoyant — ultimately rising to the surface. Like airborne gliders, wings convert this vertical lift into horizontal motion.

Thompson and his colleagues from the University of East Anglia dropped their gliders into the ocean off the coast of the Antarctic Peninsula in January 2012; the robotic vehicles then spent the next two months moving up and down through the water column — diving a kilometer below the surface of the water and back up again every few hours — exploring the Weddell Sea off the coast of Antarctica. 

As the gliders traveled, they collected temperature and salinity data at different locations and depths of the sea. The glider’s up and down capability is important for studying ocean stratification, or how water characteristics, such as density, change with depth, Thompson says. 

Caltech Seaglider being released into the Weddell Sea off the coast of the Antarctic Peninsula in January 2012. The glider would be left to sample the region for about two months, measuring temperature, salinity and ocean currents to better understand how the ocean contribute to heat transport towards the Antarctic coastline. Image credit: Andrew Thompson/Caltech“If it was only temperature that determined density, you’d always have warm water at the top and cold water at the bottom. But in the ocean you also have to factor in salinity; the higher the salinity is in the water, the more dense that water is and the more likely it is to sink to the bottom,” he says.

In Antarctica the combined effects of temperature and salinity create an interesting situation, in which the warmest water is not on top, but actually sandwiched in the middle layers of the water column. “That’s an additional problem in understanding the heat transport in this region,” he adds. You can’t just take measurements at the surface, he says. “You actually need to be taking a look at that very warm temperature layer, which happens to sit in the middle of the water column. That’s the layer that is actually moving toward the ice shelf.”

The results from the gliders revealed that the heat was actually coming from a less predictable source: eddies, swirling underwater storms that are caused by ocean currents.

“Eddies are instabilities that are caused by ocean currents, and we often compare their effect on the ocean to putting a spoon in your coffee,” Thompson says. “If you pour milk in your coffee and then you stir it with a spoon, the spoon enhances your ability to mix the milk into the coffee and that is what these eddies do. They are very good at mixing heat and other properties.”

Oceanographers Liz Creed (Kongsberg, Inc.) and Andy Thompson (Caltech) run through a series of tests in preparation for the release of a Seaglider into the Weddell Sea in January 2012. Image credit: Alan Jamieson/Caltech Because the gliders could dive and surface every few hours and remain at sea for months, they were able to see these eddies in action—something that ships and satellites had previously been unable to capture.

“Ocean currents are variable, and so if you go just one time, what you measure might not be what the current looks like a day later. It’s sort of like the weather — you know it’s going to be warm in the summer and cold in the winter, but on a day-to-day basis it could be cold in the summer just because a storm came in,” Thompson says. “Eddies do the same thing in the ocean, so unless you understand how the temperature of currents is changing from day to day — information we can actually collect with the gliders — then you can’t understand what the long-term heat transport is.”

In future work, Thompson plans to couple meteorological data with the data collected from his gliders. In December, the team will use ocean gliders to study a rough patch of ocean between the southern tip of South America and Antarctica, called the Drake Passage, as a surface robot, called a Waveglider, collects information from the surface of the water. “With the Waveglider, we can measure not just the ocean properties, but atmospheric properties as well, such as wind speed and wind direction. So we’ll get to actually see what’s happening at the air-sea interface.”

In the Drake Passage, deep waters from the Southern Ocean are “ventilated” — or emerge at the surface — a phenomenon specific to this region of the ocean. That makes the location important for understanding the exchange of carbon dioxide between the atmosphere and the ocean. “The Southern Ocean is the window through which deep waters can actually come up to ‘see’ the atmosphere” — and it’s also a window for oceanographers to more easily see the deep ocean, he says. “It’s a very special place for many reasons.”

The work with ocean gliders was published in a paper titled “Eddy transport as a key component of the Antarctic overturning circulation.” Other authors on the paper include Karen J. Heywood of the University of East Anglia, Sunke Schmidtko of GEOMAR Helmholtz Centre for Ocean Research Kiel, Germany, and Andrew Stewart, a former postdoctoral scholar at Caltech who is now at UCLA. Thompson’s glider work was supported by an award from the National Science Foundation and the UK’s Natural Environment Research Council; Stewart was supported by the President’s and Director’s Fund program at Caltech.

You Might Also Like

Filed Under: Robotics/Drones

Primary Sidebar

EE Engineering Training Days

engineering

Featured Contributions

Five challenges for developing next-generation ADAS and autonomous vehicles

Robust design for Variable Frequency Drives and starters

Meeting demand for hidden wearables via Schottky rectifiers

GaN reliability milestones break through the silicon ceiling

From extreme to mainstream: how industrial connectors are evolving to meet today’s harsh demands

More Featured Contributions

EE Tech Toolbox

“ee
Tech Toolbox: Internet of Things
Explore practical strategies for minimizing attack surfaces, managing memory efficiently, and securing firmware. Download now to ensure your IoT implementations remain secure, efficient, and future-ready.

EE Learning Center

EE Learning Center
“ee
EXPAND YOUR KNOWLEDGE AND STAY CONNECTED
Get the latest info on technologies, tools and strategies for EE professionals.
“bills

R&D World Podcasts

R&D 100 Episode 10
See More >

Sponsored Content

Advanced Embedded Systems Debug with Jitter and Real-Time Eye Analysis

Connectors Enabling the Evolution of AR/VR/MR Devices

Award-Winning Thermal Management for 5G Designs

Making Rugged and Reliable Connections

Omron’s systematic approach to a better PCB connector

Looking for an Excellent Resource on RF & Microwave Power Measurements? Read This eBook

More Sponsored Content >>

RSS Current EDABoard.com discussions

  • Will this TL084C based current clamp circuit work?
  • Mains inverter with switching node going out on the mains cable!?
  • ISL8117 buck converter blowing up
  • MOSFET thermal noise in Weak vs Strong inversion
  • System verilog constraint error

RSS Current Electro-Tech-Online.com Discussions

  • Kawai KDP 80 Electronic Piano Dead
  • My Advanced Realistic Humanoid Robots Project
  • FSK SER on the same symbols
  • Wideband matching an electrically short bowtie antenna; 50 ohm, 434 MHz
  • using a RTC in SF basic
Search Millions of Parts from Thousands of Suppliers.

Search Now!
design fast globle

Footer

EE World Online

EE WORLD ONLINE NETWORK

  • 5G Technology World
  • Analog IC Tips
  • Battery Power Tips
  • Connector Tips
  • DesignFast
  • EDABoard Forums
  • Electro-Tech-Online Forums
  • Engineer's Garage
  • EV Engineering
  • Microcontroller Tips
  • Power Electronic Tips
  • Sensor Tips
  • Test and Measurement Tips

EE WORLD ONLINE

  • Subscribe to our newsletter
  • Teardown Videos
  • Advertise with us
  • Contact us
  • About Us

Copyright © 2025 · WTWH Media LLC and its licensors. All rights reserved.
The material on this site may not be reproduced, distributed, transmitted, cached or otherwise used, except with the prior written permission of WTWH Media.

Privacy Policy