Mysterious and gaping holes in the Antarctic ice explained



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Huge holes in the winter Antarctic ice floe have appeared sporadically since the 1970s, but the reason for their formation is largely mysterious.

Scientists, with the help of floating robots and seals equipped with advanced technologies, may now have the answer: the so-called polynyas (in Russian "open water") seem to be the result of storms and salt , according to new research.

<p class = "canvas-atom-canvas-text Mb (1.0em) Mb (0) – sm Mt (0.8em) – sm" type = "text" content = "The polynyas have attracted much attention in the latter time because two very large ones open in the Weddell Sea in 2016 and 2017; in the latter case, the open waters extend over 298,100 square kilometers (115,097 square miles), according to an article published in the newspaper in April Geophysical Research Letters. "data-reactid =" 13 "> The polynyas have attracted a lot of attention lately, as two very large ones opened their doors in the Weddell Sea in 2016 and 2017. In this last occasion, the open waters are Spread over 298,100 km 2 (298,100 km 2).), According to an article published in April in the journal Geophysical Research Letters.

<p class = "canvas-atom canvas-text Mb (1.0em) Mb (0) – sm Mt (0.8em) – sm" type = "text" content = "Now the most comprehensive look at the l & # 39; ocean The conditions governing the formation of polynyas reveal that these open water expanses develop due to short-lived and particularly unpleasant climatic variations.The polynyas also release much heat from the oceanic depths into the atmosphere, with consequences that scientists are still working.[[[[Antarctica: the bottom of the world covered with ice (Photos)]"data-reactid =" 14 "> The most comprehensive picture ever taken of ocean conditions during the formation of polynyas reveals that these expanses of open water develop due to short-lived and particularly unpleasant climatic variations. Polynies also release much heat from deep oceans into the atmosphere, with consequences that scientists are still working on. [Antarctica: The Ice-Covered Bottom of the World (Photos)]

<figcaption class = "C ($ c-fuji-gray-h) Fz (13px) Py (5px) Lh (1.5)" title = "The hole in the pack ice off the Antarctic coast was spotted by a satellite of NASA September 25, 2017. NASA"data-reactid =" 22 ">

The hole in the pack ice off the Antarctic coast was spotted by a NASA satellite on September 25, 2017. NASA

<p class = "canvas-atom-canvas-text Mb (1.0em) Mb (0) – sm Mt (0.8em) – sm" type = "text" content = "" It can change the weather around AntarcticEthan Campbell, head of the study, PhD student in oceanography at the University of Washington, told Live Science. "Maybe further." "data-reactid =" 26 ">" This could change the weather around Antarctica ", Ethan Campbell, head of study, PhD student in oceanography at the University of Washington, told Live Science. "Maybe further."

Observation of the ocean

<p class = "canvas-atom canvas-text Mb (1.0em) Mb (0) – sm Mt (0.8em) – sm" type = "text" content = "Researchers already suspected that storms had played a role in the creation of polynyas in recent years: article published in April by scientists of the atmosphere in the Journal of Geophysical Research: Atmospheres pointed out a particularly violent storm with wind speeds of up to 72 miles at the time (117 kilometers) in 2017. "data-reactid =" 28 "> Researchers already suspected that storms had played a role in creating polynyas in recent years An article published in April by Atmospheric Scientists in the Journal of Geophysical Research: Atmospheres reported a particularly violent storm with winds reaching up to 117 km / h in 2017.

But even though the winter storms of 2016 and 2017 have been extreme, temperate seas are the norm in winter Antarctica, said Campbell.

"It was only storms, we would see polynya all the time, but it's not the case," he said. Instead, large polynyas are relatively rare. There were three huge ones in 1974, 1975 and 1976, but nothing important until 2016.

Campbell and his team pulled data from two human-sized robotic floats deployed in the Weddell Sea as part of the National Carbon and Climate Carbon and Climate Modeling and Observation Project in the Southern Ocean. Science Foundation (SOCCOM). The floats drift in currents about a mile and a half from the surface of the ocean, said Campbell, collecting data on water temperature, salinity and carbon content.

For comparison purposes, the researchers also used observations made all year round by Antarctic research vessels and even scientific seals – wild pinnipeds equipped with small instruments to collect ocean data while the animals are performing. their usual travels.

Stormy seas

<p class = "canvas-atom canvas-text Mb (1.0em) Mb (0) – sm Mt (0.8em) – sm" type = "text" content = "Together, these observations explain the whole history of 2016 and 2017. The first ingredient, Campbell said, was part of a climate pattern called Southern Annular Mode, the polar version of El Niño. Cambell said that a regular climatic variation can result in winds farther away from the Antarctic coast, in which case they become weaker, or closer to the coast, becoming stronger. When variability brings the winds closer and stronger, it creates a warm, salty water rise from the depths of the Weddell Sea to the colder, cooler surface of the ocean.[[[[In photos: a research vessel is heading for a "hidden" Antarctic ecosystem]Together, these observations explain the complete history of the polynyas of 2016 and 2017. The first ingredient, said Campbell, was part of a climatic pattern called Southern Annular Mode, the Polar version of El Niño According to Mr. Cambell, a steady climatic variation can cause winds farther away from the Antarctic coast, in which case they weaken, or get closer to the coast, becoming stronger. warm and salty from the depths of the Weddell Sea to the cooler, cooler surface of the ocean. [In Photos: Research Vessel Headed to ‘Hidden’ Antarctic Ecosystem]

This type of climate and the resulting upwellings made the ocean surface exceptionally salty in 2016, explained Campbell, which allowed the water to mix. more easily vertically. In general, salinity differences separate the oceanic layers, just as the less dense hydrocarbons float above the water and refuse to mix. But because the surface of the ocean was exceptionally salty, there was less difference between the surface and the deeper waters.

"The ocean was exceptionally salty on the surface, which made the barrier to mixing much lower," Campbell said.

From now on, the whole ocean we needed was a little hectic. And the winters of 2016 and 2017 provided the spoon. The big storms created wind and waves that mixed the water vertically, bringing warm water from the bottom of the ocean that melted the sea ice.

The effects of the polynyas that have formed are still somewhat mysterious. The researchers found that the ocean's interior below them cooled by 0.26 degrees Celsius (0.36 degrees Fahrenheit). This heat could change local weather conditions and even change the winds around the world, Campbell said.

<p class = "canvas-atom canvas-text Mb (1.0em) Mb (0) – sm Mt (0.8em) – sm" type = "text" content = "More disturbing, he says, it's that deep ocean waters exposed to the atmosphere during a polynya are potentially rich in carbon.The deep waters of Antarctica are the cemeteries of marine life, which release carbon during their decomposition. carbon enters the atmosphere via polynyas, these openings climate changeAccording to Mr. Campbell, "data-reactid =" 41 "> More worrying, deep ocean waters exposed to the atmosphere during a polynya are potentially rich in carbon. Antarctica are the cemeteries of marine life, which release carbon If these carbon emissions enter the atmosphere through polynyas, these openings in open water could contribute slightly to climate change, said Mr. Campbell.

Campbell said the new study should help scientists better understand climate change in Antarctica. Current models of Antarctica seem to predict more polynyas than it exists, Campbell said. Now, climate modellers will have more data to improve these predictions, creating a better virtual Antarctic to understand climate change.

<p class = "canvas-atom canvas-text Mb (1.0em) Mb (0) – sm Mt (0.8em) – sm" type = "text" content = "The search was published on June 10 in the newspaper Nature. "data-reactid =" 43 "> The research was published June 10 in the journal Nature.

<p class = "canvas-atom canvas-text Mb (1.0em) Mb (0) – sm Mt (0.8em) – sm" type = "text" content = "Originally posted on & nbsp;Science live"data-reactid =" 48 ">Originally published on Live Science.

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