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X-WR-CALNAME;VALUE=TEXT:ClimaTea Journal Club: "weakening of the stratospheric polar vortex by Arctic sea-ice loss"
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SUMMARY:ClimaTea Journal Club: "weakening of the stratospheric polar vortex by Arctic sea-ice loss"
DESCRIPTION:<p>This week GS Yang Tian will lead the discussion on the attached paper titled ”weakening of the stratospheric polar vortex by Arctic sea-ice loss." Attached is also a related review paper by Cohen et al (2014).</p><p></p><div>Briefly: "In spite of mean global surface warming, an ostensibly large number of high-impact cold extremes have occurred in the Northern Hemisphere mid-latitude over the past decade. One hypothesis is that Arctic amplification, i.e. the greater warming of the Arctic compared with lower latitudes, alters the large scale circulation to states that favor extreme cold events in the multitudes. However, the mechanisms proposed to dynamically link the midlatitude extremes to high latitude warming are a matter of intense debate. The authors combined observational analyses (ECMWF ERA-Interim data) with model experiments (CAM5) to propose a link between Arctic sea ice loss and weakening of stratospheric polar vortex, the latter preferentially induces a negative phase of Arctic Oscillation which leads to low temperatures. The physical mechanism suggested here is that sea ice loss in the Barents-Kara (B-K) sea induces the development of a planetary scale wave train that propagates upward into the stratosphere, this constructively interferes with climatological planetary-scale waves and likely weakens the polar vortex, other factors include Eurasian snow cover, the Quasi Biannual Oscillation, the ENSO, and solar activity may also play roles."</div>
LOCATION:HUCE Seminar Room
STATUS:CONFIRMED
DTSTART:20141104T200000Z
DTEND:20141104T210000Z
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