Heavystorms Play An Important Role In Collapse Of Antarctic Shelf

Warmer temperatures and changes in ocean circulation and salinity aredriving the breakdown of ice sheets in Antarctica, but a new study suggests that intense storms can help the system exceed the limit.

A research team led by US and Korean scientists deployed three moorings with hydrophones attached to the Nansen ice shelf in the Ross Sea ofAntarcticain December 2015 and were able to record hundreds of short-termbroadband signals that indicate the fracture of the ice shelf.

The"earthquakes" took place mainly between January and March2016, and the front of the ice sheet became two giant icebergs onApril 7. The day the icebergs moved away from the platform coincidedwith the largest low-pressure storm system in the region. They had registered it in the last seven months, say the researchers.

The results of the study will be published this week in Frontiers in Earth Science.

"It seems that while the icebergs had been released from the main icesheet, they remained close until the combination of high winds and astrong low-pressure storm combined to release them," said BobDziak, a research oceanographer at the National Oceanic. and theAtmospheric Administration and lead author of the study.

"Theprocess behind the separation and separation of Antarctic ice shelvesis not fully understood, and our study suggests that storms play alittle appreciated role in their separation," said Dziak.

NextJanuary, Dziak and researchers from Oregon State University and theKorea Polar Research Institute will return to Antarctica to replace the three hydrophones near Nansen and deploy acoustic sensors nearthe huge Thwaites glacier, called one of the most important anddangerous. Glaciers on the planet.

The huge glacier has developed a large cavity due to the rapid melting ofthe glacier due to climate change. It contained an estimated 14billion tons of ice and most of it melted in the last 3-4 years.Since it is thought that it "slows" other glaciers, itscollapse could have a significant impact on sea level rise worldwide,as well as on the structure and environment of West Antarctica.

Dziak,who has a courtesy appointment at the Oregon State School of Earth, Ocean and Atmosphere Sciences, said hydrophones provide a new source of data for scientists studying Antarctica.

"Although the leading edge of the Nansen ice shelf broke, the icebergs remainedin place for several months, so GPS sensors or satellite images didnot make it clear that a large piece of the platform had fallen,"Dziak said. "But our underwater hydrophones recorded thesounds on the shelf dividing months before.

"We hope that the deployment of additional underwater sensors inAntarctica will give us similar warnings if the Thwaites ice shelfbegins to give birth."

By:Preeti Narula

Content:https://www.sciencedaily.com/releases/2019/07/190718164857.htm