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SUMMARY:Determining the source regions for surface to stratosphere transpo
 rt: A retro-transport approach - Phil Haines (UCL)
DTSTART:20131107T141500Z
DTEND:20131107T153000Z
UID:TALK48304@talks.cam.ac.uk
CONTACT:Dr Amanda Maycock
DESCRIPTION:The transport of `very-short lived' species (i.e.\, chlorinate
 d and brominated hydrocarbons) from the planetary surface to the stratosph
 ere is known to have a significant impact on stratospheric ozone. Several 
 studies have shown that the amount of chlorine and bromine reaching the st
 ratosphere is strongly dependent upon the geographical location of the sou
 rce. To investigate this geographical dependence carefully involves simult
 aneously determining the sensitivity of a single quantity\, such as the fl
 ux of a species into the stratosphere\, upon emissions from many possible 
 source locations. It therefore makes sense to adopt an adjoint approach. \
 n\nOne such approach\, intended to maximise the symmetry between forward a
 nd adjoint models\, is Eulerian backtracking [Hourdin and Talagrand 2006].
   The advantages of Eulerian backtracking over other approaches include ea
 se-of-use and stability of model solutions.  We describe RETRO-TOM\, a new
  model developed using Eulerian backtracking and intended to serve as a hi
 ghly-accurate adjoint to the chemistry transport model TOMCAT.  We then ad
 dress the question of how the (time-averaged) stratospheric flux of a fini
 te lifetime species depends upon the location of its surface sources by pr
 esenting sensitivity maps obtained using RETRO-TOM.\n
LOCATION:Unilever Lecture Theatre\, Department of Chemistry
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