New research suggests warm winds in Antarctica are becoming more prevalent and are playing a role in the weakening the continent’s ice shelves.
(From UPI / By Brooks Hays) — Föhn, or foehn, winds are warm, dry winds that blow downhill on the leeward side of a mountain range. New research by scientists with the British Antarctic Survey suggests foehn winds in Antarctica are occurring farther south and more frequently than previously thought.
Researchers believe these warm, dry winds are worsening vulnerabilities among Antarctica’s ice shelves. Melting caused by the winds could lead to the collapse of the Larsen C ice shelf.
In 1995, the Larsen A shelf collapsed. In 2002, Larsen B did the same. Scientists believe the collapse was triggered by crevices and cracks that were widened and deepened by the flow of surface meltwater. Researchers hypothesized that foehn winds melted the water flowing through the cracks.
Researchers found foehn winds frequently blow across the Larsen C ice shelf, the continent’s largest ice shelf. The winds blow year round but are most common in the spring.
“What’s new and surprising from this study is that föhn winds occur around 65 percent of the time during the spring and summer,” Jenny Turton, a researcher at BAS and Leeds University, said in a news release. “Whilst a high number occur in spring, the combined warming over a number of days leads to much more surface melting than was experienced during days without föhn winds.”
Melting and refreezing makes the ice shelf’s surface more vulnerable to future melting.
“We know the ice shelf often melts a little during summer, however we have found that when föhn events occur as early as September — three months earlier than the start of the summer melt season — the ice shelf surface is melting,” Turton said. “Now that we know how prevalent and spatially extensive these winds are, we can look further into the effect they are having on the ice shelf.”
Read the full story here: http://www.upi.com/Science_News/2017/04/25/Warm-winds-are-weakening-Antarctic-ice-shelves/2111493133993/