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Antarctica ’s ice paradox has yet another puzzling stratum . Not only is the amount of sea icing increase each twelvemonth , but an underwater automaton now shows the ice is also much thicker than was previously thought , a new study report .
The discovery adds to the ongoing whodunit ofAntarctica ’s amplify sea ice . According to climate models , the neighborhood ’s sea ice should be shrinking each year because of global warming . Instead , orbiter notice show the ice is expanding , and the continent ’s ocean ice rink has set fresh records for the past three winters . At the same time , Antarctica ’s glass rag ( the gelid ice on demesne ) is melting and retreating .
Different thicknesses of sea ice in Antarctica’s Bellingshausen Sea. Open water is dark black; older sea ice has a covering of bright white snow, and thick ice is grey.
Measuringsea glass thicknessis a crucial step in understand what ’s drive the outgrowth of sea methamphetamine hydrochloride , say study co - source Ted Maksym , an oceanographer at the Woods Hole Oceanographic Institution in Massachusetts . Climate scientist need to know if the sea ice expansion also include underwater node . [ Album : Stunning picture of Antarctic Ice ]
" If we do n’t make love how much ice is there is , we ca n’t formalise the role model we utilize to empathise the world-wide mood , " Maksym told Live Science . " It looks like there are substantial areas of thick ice that are belike not accounted for . "
The findings were published today ( Nov. 24 ) in the journal Nature Geoscience .
The robot submarine ready for launch from an icebreaker offshore Antarctica.
Like iceberg , much of Antarctica ’s floating ocean ice is underwater , hidden from satellites that trail seasonal ocean ice . And it ’s hard to take direct mensuration from ships or drilling , because the thickest meth is also the hardest to reach , Maksym order .
The researchers were stuck aboard an icebreaker in 20 - foot - thick ( 6 meters ) pack ice for more than a week after take advantage of a leading , or open body of water , that accessed thick ice , he said . " Obviously that carried some risk of exposure , and we were stuck until the wind changed direction again , " he allege .
ping the glass
Over the last four years , the international group of researchers hasmapped the bottom of sea ice with an submerged robot , or autonomous submersed vehicle ( AUV ) , during two inquiry sail offshore Antarctica . The AUV can swim to a profundity of about 100 feet ( 30 m ) and has upward - looking sonar to survey the bottom of the ocean ice .
" With the AUV , you could get under ice rink that is either hard to access or hard to drill , and in each region , we find out some really thick ice , thicker than had been measured anywhere else , " Maksym said .
Almost all of the sea ice that descriptor during the Antarctic winter melting during the summer , so scientists had assumed most of the chalk never grew very thick . Previous studies suggest the methamphetamine hydrochloride was normally 3 to 6 feet ( 1 to 2 m ) thick , with a few rare spots make up to 16 understructure ( 5 m ) in heaviness . For comparing , most of the Arctic ocean ice is doubly as wooden-headed ( 6 to 9 feet , or 2 to 3 m ) , with some neighborhood covered with 12 to 15 foot ( 4 to 5 m ) of chicken feed . [ 50 Amazing fact About Antarctica ]
Therobot sub surveys , which were spot - checked by drilling and shipboard tests , suggest Antarctica ’s average ice heaviness is considerably higher than old estimates . On average , the heaviness of the ice was 4.6 to 18 foot ( 1.4 to 5.5 m ) . In the three regions it surveyed , the robot sub found that distort , thickened ice accounted for at least half of and as much as 76 percent of the full ice intensity , the researchers describe .
" Our study shows that we ’re probably overlook some of this chummy ice , and we need to prove to account for that when we essay to equate what we see in good example and satellites to what we see in the field , " Maksym order .
The thick ice assess during the study was about 65 foot ( 20 m ) chummy , in the Bellingshausen Sea , Maksym told Live Science . In the Weddell Sea , the maximum ice thickness hit more than 45 foot ( 14 m ) , and offshore of Wilkes Land , the ice was about 53 feet ( 16 m ) thick .
Next step
These thick , craggy ice floe in all probability would n’t survive without the fierce current of air that circleAntarcticafrom Occident to east , the researchers said . Winter storm whop up the ice , freezing and reforming the rubble into new , thicker crank . " It must have been comminute up a tremendous amount and [ the floes ] piled up on top of each other , " Maksym say . " The ice can generate enormous amount of forcefulness if you have these strong wind . [ The wind ] is like an accordion , stretching it out and slop it back together again . "
The researchers ' next step is to measure how much of Antarctica ’s total ocean water ice this stocky ice represent . Maksym said it could be a " reasonably significant country of the pack . "
Thesea ice growth around Antarcticahas average about 1.2 percent to 1.8 percent per decade between 1979 and 2012 , according to the 2013 Intergovernmental Panel on Climate Change ’s Fifth Assessment Report . The increases are digest primarily in the Ross Sea in western Antarctica . Sea ice in the nearby Bellingshausen and Amundsen seas has importantly decreased . Researchers suspect these regional differences could lead from strong winds or increase meltwater from the Antarctic ice rag , or a combination of both factors .
