BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Talks.cam//talks.cam.ac.uk//
X-WR-CALNAME:Talks.cam
BEGIN:VEVENT
SUMMARY:MCM Box Modelling of the OP3 Aircraft Campaign - Mr Daniel Stone\,
  School of Chemistry\, University of Leeds
DTSTART:20100112T141500Z
DTEND:20100112T151500Z
UID:TALK21692@talks.cam.ac.uk
CONTACT:Dr Francis Pope
DESCRIPTION:Recent evidence suggests a significant failing in our understa
 nding of the atmospheric chemistry of isoprene under low NOx conditions\, 
 with important consequences for modelling of OH and the climate gases meth
 ane and ozone.  \n\nIsoprene is the dominant biogenic volatile organic com
 pound emitted into the atmosphere\, with an estimated emission rate of 500
  Tg/year.  Removal of isoprene from the troposphere is dominated by its ra
 pid reaction with the OH radical.  As a result\, global models predict low
  OH concentrations in regions with low NOx and high isoprene emissions\, y
 et field observations of OH in such environments report unexpectedly high 
 concentrations.  Atmospheric models have been unable to replicate OH obser
 vations in such regions\, and indicate a previously unidentified source of
  OH linked to isoprene.\n\nSeveral recent experimental and theoretical stu
 dies have also challenged our understanding of isoprene oxidation in the a
 tmosphere\, and there is a growing body of evidence from field observation
 s\, laboratory experiments and theoretical work suggesting that the curren
 t understanding of the OH-initiated oxidation of isoprene is incomplete.\n
 \nIn this work we use the Master Chemical Mechanism (MCM) in the Dynamical
 ly Simple Model of Atmospheric Chemical Complexity (DSMACC) to investigate
  recently proposed changes to the mechanism for isoprene oxidation current
 ly adopted in atmospheric models.  The model is constrained to observation
 s made onboard the BAe146 FAAM research aircraft during the Oxidant and Pa
 rticle Photochemical Processes (OP3) field campaign over Borneo in July an
 d August 2008\, and comparisons between the OH concentrations obtained fro
 m the model and those observed during the field campaign provide a test fo
 r the understanding of isoprene oxidation in this region.\n\nResults indic
 ate a requirement for additional OH sources related to isoprene\, with the
  model vastly underestimating the observed OH concentrations.  Implementat
 ion of recent findings from experimental and theoretical investigations of
  isoprene chemistry result in significant improvements in model success\, 
 and provide important insights to previously unknown sources of OH in the 
 atmosphere.\n
LOCATION:Unilever Lecture Theatre\, Department of Chemistry
END:VEVENT
END:VCALENDAR