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SUMMARY:Stratosphere-Troposphere coupling during Arctic Polar-night Jet Os
 cillation Events - Peter Hitchcock\, DAMTP\, University of Cambridge
DTSTART:20141111T140000Z
DTEND:20141111T150000Z
UID:TALK55312@talks.cam.ac.uk
CONTACT:Dr. Pranab Deb
DESCRIPTION:The Polar-night Jet Oscillation (PJO) has been described by Ku
 roda and Kodera as a mode of intra-seasonal variability of the Arctic Pola
 r-night Jet\, in which wind and temperature anomalies migrate poleward fro
 m the tropics in the upper stratosphere\, then downward to the lower strat
 osphere over a timescale of several months. This mode has been strongly im
 plicated in one pathway for solar variability to influence tropospheric cl
 imate. In the first part of this talk I will argue that the most coherent 
 manifestation of the PJO is during extremely large amplitude events follow
 ing a subset of major sudden stratospheric warmings\, and that the dynamic
 s of the anomalies' descent can be well understood in terms of the structu
 re of radiative timescales and the filtering of gravity waves.\n\nIn the s
 econd part of the talk I will demonstrate the relevance of these 'PJO even
 ts' to stratosphere-troposphere coupling in a series of careful experiment
 s with the Canadian Middle Atmosphere Model\, a comprehensive\, stratosphe
 re-resolving model.\n
LOCATION:British Antarctic Survey\, Room 307
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