BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//talks.cam.ac.uk//v3//EN
BEGIN:VTIMEZONE
TZID:Europe/London
BEGIN:DAYLIGHT
TZOFFSETFROM:+0000
TZOFFSETTO:+0100
TZNAME:BST
DTSTART:19700329T010000
RRULE:FREQ=YEARLY;BYMONTH=3;BYDAY=-1SU
END:DAYLIGHT
BEGIN:STANDARD
TZOFFSETFROM:+0100
TZOFFSETTO:+0000
TZNAME:GMT
DTSTART:19701025T020000
RRULE:FREQ=YEARLY;BYMONTH=10;BYDAY=-1SU
END:STANDARD
END:VTIMEZONE
BEGIN:VEVENT
CATEGORIES:Quantitative Climate and Environmental Science Sem
 inars
SUMMARY:Tropical rainfall\, Rossby waves and initialised c
 limate predictions - Adame Scaife (Met Office Hadl
 ey Centre)
DTSTART;TZID=Europe/London:20160118T130000
DTEND;TZID=Europe/London:20160118T140000
UID:TALK63804AThttp://talks.cam.ac.uk
URL:http://talks.cam.ac.uk/talk/index/63804
DESCRIPTION:Skilful climate predictions of the winter North At
 lantic Oscillation and Arctic Oscillation out to a
  few months ahead have recently been demonstrated 
 but the source of this predictability remains larg
 ely unknown. Here we investigate the role of the t
 ropics in this predictability.  We show high level
 s of skill in tropical rainfall predictions\, part
 icularly over the Pacific but also the Indian and 
 Atlantic Ocean basins.  Rainfall fluctuations in t
 hese regions drive clear signatures in tropical an
 d extratropical atmospheric circulation that are a
 pproximately symmetric about the equator in boreal
  winter. We show how these patterns can be explain
 ed as steady poleward propagating linear Rossby wa
 ves emanating from just a few key source regions. 
  The sources of these waves are more or less activ
 e as tropical rainfall varies from winter to winte
 r but they do not change position because the wave
  sources are anchored to regions of strong vortici
 ty gradient associated with the extratropical jets
 .  Finally\, we show that predicted tropical rainf
 all explains a sizeable fraction of the predicted 
 year to year variance of the winter North Atlantic
  Oscillation.
LOCATION:MR4\, Centre for Mathematical Sciences
CONTACT:Doris Allen
END:VEVENT
END:VCALENDAR