publiek kul chemie 232005

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UTLS ozone and ozone trends D. Fonteyn (My
apologies) Given by W. Lahoz (My thanks)
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• Importance UTLS
• relatively large (but variable) ozone trends
• very high climate sensitivity
• crucial region modulating stratospheric entry of
  tropospheric pollutants
• growing commercial aviation

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• Problems UTLS studies
• very complex region (dynamics and chemistry on a
  variety of scales)
• high demands on modeling capabilities
• limited amount of satellite observations with
  large uncertainties rely on in-situ measurements

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UTLS combination of mixing and chemistry
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• Upper Troposphere
• Emission of chemical species
• Ozone production
• Oxidation capacity
• Species influencing radiatif budget

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• Lower Stratosphere
• Ozone destruction (ClOx, BrOx, NOx, heterogeneous
  chemistry)
• Species influencing radiatif budget

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• Upper Troposphere Lower Stratosphere Studies
• STE Stratosphere Troposphere Exchange
• Dynamical processes
• Chemical processes
• Climate
• All Linked

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• Overview of ozone chemistry?
• Huge task
• Chemical processes are relatively well known
• Tropospheric chemistry
• Stratospheric chemistry
• Coupling with emissions, dynamics, climate change
  makes it extremely vast.

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UTLS slow chemistry and fast mixing
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UTLS distinct tracer relationships
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• Models Observations
• Climatology dynamical features present in
  species distributions

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gtgt Park et al, JGR 2004
Methane distribution at 136 hPa in July. Maximum
near Asian monsoon and secundary maximum near
North America
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gtgt Park et al, JGR 2004
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• Models Observations
• Climatology
• Convective driven methane distribution, models
  agree with observations, gradients do not agree
• Lightning NOx production qualitative agreement
  but not in vertical
• ? Ozone ?

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gtgt Kuell et al., JGR 2005
Detrended CFC 11 distribution at 100 hPa in the
TRACHT region during the time period from 1013
August 1997 as measured by CRISTA (upper map) and
modeled by EURAD (interpolated to the CRISTA
measurement grid lower map). The EURAD data have
a negative bias of about 20 pptv. Dynamical
features a mid-latitude blocking event
characterized by an omega circulation pattern
with a persistent cutoff low at its western wing.
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• Models Observations
• Satellite observations allow to detect dynamical
  effects in CFC 11 distributions on an event
  basis.
• Event modelling in qualitative agreement

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Models Observations shifting towards event
chemistry (UT) Brunner D., et al., ACP, 2005 An
evaluation of the performance of chemistry
transport models. Part 2 Detailed comparison
with two selected campaigns
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gtgt Brunner et al., ACP 2005
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gtgt OUTLINE
Composites of PEM-Tropics A time series.
Measurements at 035 S and 400200 hPa (about
7.212 km) only. Flight numbers are indicated at
the top of each panel. Black measurements.
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gtgt OUTLINE
Composites of SONEX time series. Only
measurements between 350 and 200 hPa are included.
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Models Observations shifting towards event
chemistry (UT) Senistivity to emissions,
biomass burning, lightning, aircraft ? Large
model variability
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• Problems UTLS studies
• Other uncertainties, winds
• Bregman mass conserving properties
• Comparing with MOZAIC aircraft campaign

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gtgt Bregman, B., et al., ACP, 2003
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• Ozone UTLS trends
• Observations
• LS ozone depletion related and recovery
• UT pollution effects
• VERY LONG term trends models

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gtgt WMO, 2002
Ozone decrease in lower stratosphere in Northern
Mid-latitudes. The period 1980 2000 shows less
decrease than 1980 1996.
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gtgt OUTLINE
Vertical discriminated deseasonalized ozone
evolution from ozonesondes NH.
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gtgt MOZAIC trends, Thouret, V., et al., ACPD, 2005
Time series of ozone monthly means in the UT over
the three selected regions Europe, Eastern US and
Iceland.
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gtgt OUTLINE
Time series of ozone monthly means in the LS over
the three selected regions Europe, Eastern US and
Iceland.
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MOZAIC Ozone UTLS trends Apparent
discrepancies UT increase, high compared to
literature LS increase, decreased
expected ? Effect of period, effect of location
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gtgt GAUSS, M., et al., ACPD, 2005
Very long term trend 1850 2000 Chemical change
induced Dynamical change induced
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A flavour of what to expect