Atmospheric Composition Changes: causes and processes involved

1
Atmospheric Composition Changes causes and
processes involved

• R. Zander
• Univ. Liège - Groupe Infrarouge de Physique
  Atmosphérique et Solaire (ULg-GIRPAS)
• and
• M. De Mazière
• Belgian Institute for Space Aeronomy (BIRA-IASB)

2
Context

• The atmosphere is changing
• Natural variations (solar variations, volcanic
  activity, )
• Anthropogenic changes (industrial, agricultural,
  traffic, )
• To detect, understand and forecast the changes
  requires a long-term, integrated strategy
  including field observations (space and ground),
  modelling, and laboratory experiments (molecular
  spectroscopy, chemical reaction schemes and
  analysis techniques, )
• The global dimension of the problem requires an
  internationally coordinated effort

3
How have the stratospheric Ozone layer and the UV
radiation at the surface changed?

• Tools / expertise
• Belgian contributions to the international
  observing networks have expanded new
  instruments, observation and analysis techniques
  from space and ground have been developed

• Advanced modelling and short-term forecasting
  techniques have become operational example
  BASCOE

• Dedicated laboratory techniques to determine
  molecular spectroscopic parameters

• Additional 15 years of data (stratospheric gases,
  climate and source gases, aerosols, UV) have been
  submitted to international databases, supporting
  detection of changing trends

• Particular findings
• The gradual decrease of the stratospheric O3
  layer in the nineties was observed at all Belgian
  stations at Uccle it amounts to -4 from 1982 to
  2002

4
How have the stratospheric Ozone layer and the UV
radiation at the surface changed? (cont.)

• In June 1991, the Mt Pinatubo volcano
  (Philippines) has erupted. The significant
  increase in aerosol loading on a global scale was
  observed from space. The consequent decrease of
  the abundances of O3 and NO2 was quantified at
  Jungfraujoch and in Uccle.

• An anti-correlation between the amount of
  stratospheric O3 and the UV irradiance at the
  surface has been confirmed at Uccle

• The chlorine loading in the stratosphere was seen
  to stabilise around 1997, then to start
  decreasing stratospheric BrO has continued to
  increase by 15 over the period 1994-2002

• The coupling ozone ? climate needs further study
  it makes the recovery of ozone uncertain at
  present.

• Policy support
• Findings have been integrated in WMO assessments,
  thus supporting Montreal Protocol adjustments and
  Kyoto Protocol

5
Air quality and climateHow has tropospheric O3
changed ?

• Tools / expertise
• for evaluating impact of regulations and
  predicting future state of the troposphere
  BELEUROS and IMAGES models

• for studying tropospheric photochemistry in the
  troposphere laboratory experiments supporting
  kinetic and chemical mechanism calculations ?
  implementation in models

• Particular findings
• Reductions of VOC emissions due to implementation
  of regulations like CAFE and CLRTAP have had a
  positive impact on the decrease of O3 peak
  concentration events
• Nevertheless background tropospheric O3 is
  predicted to continue to increase in future
  (possibly by up to 60 until 2100), due to major
  increases in developing countries. This increase
  will have a positive forcing on climate.

6
Air quality and climateImpact of particulate
matter

• Tools/ expertise
• Field monitoring at various sites in the world
• various laboratory techniques for determining the
  chemical and physical properties of aerosol
  components.

• Particular findings
• Intensive studies of the composition and physical
  properties of aerosol in Belgium and elsewhere
• Road traffic and biomass burning are the major
  origins of high levels of suspended particulate
  matter in the troposphere

• Tropospheric and stratospheric aerosol impact
  climate the contributions are highly uncertain
  still.

• At most near-city, urban background and kerbsite
  sites, Belgium will not meet European standards
  for 2010

7
Concluding remarks

• Belgium is strongly present on the international
  scene regarding Earth atmosphere research, incl.
  contributions to scientific programmation
  (scientific committees) and assessments at
  national and worldwide levels, in support of
  local, European and global environmental policies
  

• The Belgian public has been kept informed through
  the press, TV news, open public presentations,
  Web pages, etc.

• Services have been set up to issue warnings
  against high UV or alarming air pollution
  conditions.

• Continued research is needed to further monitor
  the evolution of the atmosphere, to better
  understand the links between the various
  components and scales in the atmosphere, to
  improve our forecasting ability, and to verify
  and further adjust environmental regulations and
  mitigation strategies.

8
Main contributors

• Belgian Institute for Space Aeronomy (BIRA-IASB)
• Royal Meteorological Institute of Belgium
  (KMI-IRM)
• KULeuven Division for Physical and Analytical
  Chemistry
• Univ. Antwerpen Laboratory of Biomolecular Mass
  Spectrometry and Micro and Trace Analysis Centre
• Univ. Gent Institute for Nuclear Sciences
• Univ. Libre de Bruxelles - Unité de Spectroscopie
  de lAtmosphère
• Univ. Liège - Groupe Infrarouge de Physique
  Atmosphérique et Solaire
• VITO - Remote Sensing and Atmospheric Processes