Amid researchers’ recent discovery of the first stages of the formation of an enormous iceberg from one of Antarctica’s largest and fasting moving glaciers, an international team of researchers funded by NASA and the National Science Foundation has been preparing to travel to the Pine Island Glacier to determine how changes in the waters circulating under the active ice sheet are causing the glacier to accelerate and drain into the sea.

The expedition involving a group of 13 scientists, will be the most extensive ever deployed to Pine Island Glacier, one of Antarctica’s most active, remote, and harsh spots, according to NASA.

The group, led by Robert Bindschadler, emeritus glaciologist of NASA's Goddard Space Flight Center in Greenbelt, Md., will depart from the McMurdo Station in Antarctica in mid-December and spend six weeks on the ice shelf.

“[N]obody has ever made these measurements, and this is such a dramatically changing area," he said in a video released by NASA. "[W]e just know we’re going discover something because nobody has ever looked underneath this very active ice shelf and looked at how the ocean is interacting with the ice and how the ice sheet is responding. So discovery is a sure thing.”

“The reward is the discoveries that we make and the increase in knowledge and ability to predict what these ice sheets are going to do in the future and how it will affect people worldwide,” he said.

NASA’s Goddard Space Flight Center said, during their stay, researchers will be using a combination of traditional tools and sophisticated new oceanographic instruments to measure the shape of the cavity underneath the ice shelf and determine how streams of warm ocean water enter it, move toward the very bottom of the glacier and melt its underbelly.

Giant Iceberg Forming

Earlier in the week scientists that were taking part in NASA’s “Operation Iceberg” while flying over the Pine Island Glacier, came across an iceberg in the making.

The rift had a diameter as large as 820 feet at its widest point and once it breaks off it is predicted to have about 340 square miles of surface area, which is larger than New York City at about 303 square miles and will be 1,600 feet thick mostly underneath water.

Seeking Answers about Thinning Glaciers

The Pine Island Glacier area concerns scientists most because of its potential to cause a rapid rise in sea level as satellite measurements have shown this area to have lost ice and show how surrounding glaciers continue to thin, which raises the possibility of the ice rapidly flowing out to sea.

"The project aims to determine the underlying causes behind why Pine Island Glacier has begun to flow more rapidly and discharge more ice into the ocean," said Scott Borg, director of NSF's Division of Antarctic Sciences, the group that coordinates all U.S. research in Antarctica. "This could have a significant impact on global sea-level rise over the coming century."

Melting Factors

Researchers determined that the interaction of winds, water, and ice is driving ice loss from the floating ice shelf.

“Gusts of increasingly stronger westerly winds push cold surface waters away from the continent, allowing warmer waters that normally hover at depths below the continental shelf to rise,” NASA says.

“The upwelling warm waters spill over the border of the shelf and move along the sea floor, back to where the glacier rises from the bedrock and floats, causing it to melt.”

Researchers said that the warm salty waters and fresh glacier melt water combine to make a lighter mixture that rises along the underside of the ice shelf and moves back to the open ocean, melting more ice on its way.

The team wants to find out, “how much more ice melts” so they can improve projections of how the glacier will melt and contribute to the rise in sea level.

Expedition

Bindschadler, who is leading the multidisciplinary group on the expedition, was the first person to set foot on this isolated corner of Antarctica, back in 2008, as part of initial reconnaissance for the expedition.

Scientists doubted that it was even possible to reach the “crevasse-ridden ice shelf” but Bindschadler used satellite imagery to identify an area where helicopters could land safely to transport scientists and instrumentation to and from the ice shelf, which is what they’ll be doing next month.

“The scale of the journey is quite massive, just because this is a long way from McMurdo, the major U.S. base. This is 1,400 miles away,” Bindschadler said.

Drilling Plans

The authors explained the steps to be used to gather data:

“The team will use a hot water drill to make a hole through the ice shelf. After the drill hits the ocean, the scientists will send a camera down into the cavity to observe the underbelly of the ice shelf and analyze the seabed lying approximately 1,640 feet (500 meters) below the ice. Next the team will lower an instrument package provided by oceanographer Tim Stanton of the Naval Postgraduate School in Monterrey, Calif., into the hole. The primary instrument, called a profiler, will move up and down a cable attached to the seabed, measuring temperature, salinity and currents from approximately 10 feet (3 meters) below the ice to just above the seabed.”

“A second hole will support a similar instrument array fixed to a pole stuck to the underside of the ice shelf. This instrument will measure how ice and water exchange heat. The team also will insert a string of 16 temperature sensors in the lowermost ice to freeze inside and become part of the ice shelf. The sensors will measure how fast heat is transmitted upward through the ice when hot flushes of water enter the ocean cavity.”

Studying Shelf’s Underwater Shape

Sridhar Anandakrishnan, a geophysicist with Pennsylvania State University in University Park, PA, will be studying the shape of the ocean cavity and the properties of the bedrock under the Pine Island Glacier ice shelf using a technique called reflective seismology, “which involves generating waves of energy by detonating small explosions and banging the ice with instruments resembling sledgehammers,” the Goddard Center says. Using helicopters to move from one place to another, measurements will be taken in about three dozen spots.

"The Pine Island Glacier ice shelf continues to be the place where the action is taking place in Antarctica," said Bindschadler.

"It only can be understood by making direct measurements, which is hard to do. We're doing this hard science because it has to be done. The question of how and why it is melting is even more urgent than it was when we first proposed the project over five years ago."

Published by Medicaldaily.com