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SUMMARY:Global modelling of lightning and its impact on tropospheric ozone
  chemistry - Declan Finney (Edinburgh)
DTSTART:20150615T131500Z
DTEND:20150615T141500Z
UID:TALK59020@talks.cam.ac.uk
CONTACT:Dr Amanda Maycock
DESCRIPTION:Lightning is estimated to produce around 10% of global annual 
 NOx emissions. While not the largest NOx source\, lightning has particular
  importance because it emits directly into the free troposphere instead of
  at the surface. As a result\, it is a key control on ozone production in 
 the tropical upper troposphere. As a natural emissions source\, lightning 
 also has the potential to vary with climate change if its meteorological d
 rivers are affected.\n\nThe parametrisation of lightning in most climate-c
 hemistry models uses cloud top height as a proxy. This approach is known t
 o contain large errors but there are few robust alternatives. I will prese
 nt the development of an alternative parametrisation using upward ice flux
  which is more closely linked to thunderstorm charging theory. Comparisons
  are made between our ice flux-based parametrisation and existing parametr
 isations. The upward ice flux approach is then implemented in the climate-
 chemistry model\, UKCA. UKCA is used to explore the differences in troposp
 heric ozone chemistry between the cloud top height approach versus the upw
 ard ice flux approach.
LOCATION:Unilever Lecture Theatre\, Department of Chemistry
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