BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Talks.cam//talks.cam.ac.uk//
X-WR-CALNAME:Talks.cam
BEGIN:VEVENT
SUMMARY:Ozone forcing of the coupled climate in the Southern Hemisphere - 
 David Ferreira (Reading)
DTSTART:20131202T130000Z
DTEND:20131202T140000Z
UID:TALK47891@talks.cam.ac.uk
CONTACT:Doris Allen
DESCRIPTION:Interannual variability in the Southern Annular Mode (SAM) and
  sea ice covary such that an increase and southward shift in the surface w
 esterlies (a positive phase of the SAM) coincides with an expansion of the
  sea ice cover\, as seen in observations and models alike. Yet\, the sea i
 ce extent decreases in response to sustained\, multi-decadal positive SAM-
 like wind anomalies driven by 20th century ozone depletion in modeling stu
 dies. Why does sea ice appear to have opposite responses to SAM-like varia
 bility on interannual and multidecadal timescales? We demonstrate that the
  response of sea ice and the Southern Ocean to ozone depletion is a two ti
 mescale problem.\n\nThe two timescales emerge because the fast processes o
 f the surface mixed layer and the slow dynamics of the ocean interior driv
 e Sea Surface Temperature anomalies of opposite sign in response to a SAM 
 perturbation.\n \nThis behavior is seen in two models (one with an idealiz
 ed geometry and another\, more sophisticated\, global climate model) altho
 ugh we find great uncertainties in the timescale of the transition from th
 e fast to the slow response. Processes that controls this transition are c
 larified. Implications for the interpretation of observed decadal changes 
 and future climate change in the Southern Hemisphere are discussed.\n
LOCATION:MR5\, Centre for Mathematical Sciences
END:VEVENT
END:VCALENDAR