Apr 30, 2017

Antarctica's troublesome 'hairdryer winds' - BBC News

Jonathan Amos
BBC News

[warm dry] foehn winds.. drop over the big mountains of the peninsula, raising the temperature of the air on the leeward side well above freezing.


The effect on the ice that pushes east from the Peninsula out over the Weddell Sea is clear. It produces great ponds of brilliant blue melt water at the surface.



...Examining data from 2009 to 2012, Turton and colleagues identified over 200 foehn episodes a year.

That makes them more frequent than anyone had thought previously. And the range is broader, too, with occurrences being recorded much further south on the Peninsula.

This all means their melting influence on the eastern shelf ice has very likely been underestimated.

"In summer, we expect some melt, around 2mm per day. But in spring we’re having an equal amount of melt as we are in summer during the foehn winds," Ms Turton told BBC News.

"That's significant because it’s making the melt onset earlier. We kind of expect melt in January/February time; but we’re also seeing it sometimes in September/October, in particularly frequent foehn wind conditions."



...."...On Larsen C, the ponds are still very much focused in the inlets (close to the mountains). There are few ponds on the shelf itself and so it is not quite as pre-conditioned [as Larsen B]."