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Home* News and Stories → Aus­t­fon­na: an ice cap on the move

Aus­t­fon­na: an ice cap on the move

The ice cap Aus­t­fon­na is cove­ring lar­ge parts of Nord­aus­t­land, the second-lar­gest island in the Spits­ber­gen archi­pe­la­go. The total sur­face area of Aus­t­fon­na, actual­ly a com­po­si­te of seve­ral smal­ler ice caps, is more than 8400 squa­re kilo­me­t­res.

For deca­des, Aus­t­fon­na was con­side­red to be rela­tively sta­ble: it did not suf­fer mas­si­ve loss of volu­me as many other gla­ciers in Spits­ber­gen and else­whe­re in the Arc­tic. More recent­ly, mar­gi­nal parts were thin­ning while cen­tral parts were gai­ning thic­k­ness, a beha­viour known to prepa­re a sur­ge if it lasts for some time. A sur­ge is a sud­den advan­ce whe­re a gla­cier can move for­ward over many kilo­me­t­res within a year or two, it is a result of gla­cier mecha­nics and not of cli­ma­te varia­ti­ons (see Rocks and Ice for more about gla­ciers and sur­ges). Also parts of Aus­t­fon­na are known to have sur­ged in the past, for exam­p­le Brås­vell­breen, the sou­thern part of the ice cap, in the 1930s.

Infor­ma­ti­on from satel­li­te images has now yiel­ded evi­dence for increased velo­ci­ty over lar­ge parts of Aus­t­fon­na. The ice cap is pushing into the Barents Sea, pro­du­cing vast amounts of ice­bergs and thus con­tri­bu­ting signi­fi­cant­ly to glo­bal sea level rise, curr­ent­ly more than all other gla­ciers in Spits­ber­gen tog­e­ther. Nevert­hel­ess, sci­en­tists invol­ved in obser­ving Aus­t­fon­na assu­me it will increase its volu­me in the years to come.

AECO, the arc­tic expe­di­ti­on crui­se orga­niza­ti­on, has issued a war­ning to navi­ga­te careful­ly in the­se waters, as lar­ger num­bers of ice­bergs than usu­al and chan­ges of the gla­cia­ted coast­li­ne have to be expec­ted.

Such an event, whe­re an ice cap of thou­sands of squa­re kilo­me­t­res starts to move more rapidly, is uni­que during the peri­od of detail­ed sci­en­ti­fic obser­va­ti­on and regu­lar tou­ristic access. The recent obser­va­ti­on is based on data from the Euro­pean satel­li­te Sen­ti­nel-1a. One reason the­se data have drawn more than just a litt­le bit of atten­ti­on is the fact that the satel­li­te had, at the time in ques­ti­on, not even ful­ly rea­ched its orbit, but was nevert­hel­ess able to pro­du­ce high qua­li­ty data.

The ice cap Aus­t­fon­na on Nord­aus­t­land has star­ted to move more rapidly on lar­ge parts of its huge area.


Source: BBC News.



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last modification: 2014-07-01 · copyright: Rolf Stange