The U.S. Navy’s Underwater Robots Patrol the Arctic
The Navy is analyzing research findings from efforts to deploy underwater drones beneath the ice in the Arctic Ocean to assess how quickly the ice is melting and understand how soon the U.S. and Russia will be competing for new strategic waterways in the region.
The drones had been measuring the temperature and salt content to help scientists develop more accurate computer models with which to predict the anticipated future pace of melting ice, Martin Jeffries, science advisor to the Office of Naval Research, or ONR, told Scout Warrior.
The Navy's unveiled its Updated Arctic Road Map that explains how increasing water temperatures and decreasing ice layers mean the service will need to increase the number of ships in the region over the next 20 years, Jeffries said.
Less ice in the Arctic means more open water, waterways and shipping routes in the region. More open water naturally leads to increased maritime transportation and greater competition for natural resources such as oil and gas mining.
As a result, Navy scientists are using unmanned underwater autonomous robots, or drones, to examine what's called the marginal ice zone – the portion of frozen ocean's packed ice that meets open water, Jeffries explained.
Alongside the drone research, ONR scientists have also been studying the impact of the waves upon the ice cover, water temperature and surrounding atmosphere.
“Waves can be damaging to the ice cover when they crash into the ice. It can accelerate the melting,” Jeffries said.
The idea behind the research is to assess the pace of change in the Arctic environment as a way to better predict the pace of melting ice. Faster ice melting means the opening up of new strategic waterways, passage routes and overall activity in the region among nations.
“What we're seeing as the sea ice retreats and we are exposing more ocean surface to the atmosphere - then we are seeing the surface waters become warmer due to absorption of solar radiation,” Jeffries told Scout Warrior in an interview.
Jeffries explained the scientific basis for the phenomenon by pointing to what's called the ice "albedo feedback mechanism," a term used to describe the reflectivity of the surface ice. Surface ice has a much higher "albedo," allowing it to reflect sunlight and solar radiation back into the atmosphere.
Jeffries explained that water is much darker and has a low ‘albedo' – it absorbs a lot more solar radiation which heats up the water. Warmer waters then, in turn, lead to the melting of more ice.
This story originally appeared in originally appeared in Scout Warrior here
Underwater Drones Beneath the Ice
Navy scientists have had success in the Arctic using an underwater drone called the Seaglider, a 110-pound, 2.8-meter autonomous underwater robot able to lower acoustic sensors to depths of 1,000 meters. The Seaglider, originally developed by the ONR for open ocean data collection, can be used to gather information beneath the surface of the ice, Jeffries explained.
By the end of the summer in 2014, the science team had deployed over 100 robotic platforms in the ice and the ocean, Jeffries explained.
The Seagliders were programmed to receive acoustic signals or "pings" from underwater sources suspended on cables beneath buoys frozen into the ice at fixed locations, providing precise latitude and longitude information for the drones, Jeffries explained.
An acoustic signal was sent to help us determine where in the water column below the ice the Seaglider was located so that we know accurately where each temperature and salinity measurement is, Jeffries said. Scientist then learned temperature and salinity content in the water column from the surface down to depths of 1,000 meters, he added.
Having less ice in the summer means arctic waters have greater exposure to wind and sunlight, factors which can further compound the quickening pace of melting ice, Jeffries explained.
Measuring the temperature of the water beneath the ice helps scientist understand how much greater exposure to wind and sunlight is mixing up the water column and potentially raising the water temperature.
Knowing the precise temperatures of water beneath the surface of the ice and water can provide scientists with valuable information about the extent to which wind is mixing up an otherwise highly stratified water column, moving up warmer water from deeper beneath the surface.
Warmer water currents from both the Pacific Ocean and Atlantic Ocean currently flow into the Arctic region; warm waters from the Pacific are roughly 50 meters below the surface, whereas warmer waters from the Atlantic flow as deep as 200 to 250 meters below the surface, Jeffries said.
Wind-mixing could break down this water stratification and bring heat from deeper into the ocean up closer to the surface, creating warmer water which leads to more ice melting, Jeffries said.
Jeffries explained that the wind creates more turbulence in the water column which can mix up the water column and reduce the stability – allowing heat warmer water from deeper down to come up to the surface.
The Office of Naval Research is also exploring technologies designed to improve the Navy’s ability to operate in the cold, snow, ice and fog of theArctic waters.
These efforts include technologies that allow weapons and sensors to better operate in an arctic environment and using special gear to “knock” ice off of the superstructure of a surface ship. This could also include working on technologies to build heating elements into the superstructure of the ship itself, Navy officials said.
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