Transcript Context - Belgian Federal Science Policy Office

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)
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
How have the stratospheric Ozone layer and the UV
radiation at the surface changed?
Harestua
• Tools / expertise:
– Belgian contributions to the international observing networks have
expanded ; new instruments, observation and analysis techniques from
spaceJungfraujoch
and ground have been developed
Uccle
– Advanced modelling and short-term forecasting
techniques have
become operational – example BASCOE
– Dedicated laboratory techniques to determine molecular
spectroscopic parameters OHP
– Additional 15 years of data (stratospheric gases, climate and source
gases, aerosols, UV) have been submitted to international databases,
supporting detection of changing trends
Reunion
• Particular findings:
– The gradual decrease of the stratospheric O3 layer
in the nineties was
Many more absorption lines of H2O have been observed in recent, high-quality
laboratory spectra (upper frame) as
observed
atthealllatest
Belgian
at Uccle
it amounts
to -4%
from
1982 is an
compared to those
archived in
HITRANstations;
database release.
Their accounting
in radiative
model
calculations
important contribution
to help solving the so-called “Missing Absorber” problem.
to 2002
Time series of monthly
mean total vertical column
abundances of HCl and
ClONO2 derived from
infrared solar observations
at the Jungfraujoch from
1983 to 2002. Cly, which is
of the HCl and
In June 1991, the Mt Pinatubo volcano (Philippines) the
hassum
erupted.
ClONO
2 columns
The significant increase in aerosol loading on a global
scale
was is an
surrogate of the
observed from space. The consequent decrease of theexcellent
abundances
of
total inorganic chlorine
O3 and NO2 was quantified at Jungfraujoch and in Uccle.
loading
in
the
stratosphere.
The
An anti-correlation between the amount of stratospheric
O
and
the
continuous3 lines represent
UV irradiance at the surface has been confirmed at Uccle
the mean temporal trends
of the various data sets.
How have the stratospheric Ozone layer and the UV
radiation at the surface changed? (cont.)
–
–
– The chlorine loading in the stratosphere was seen to stabilise
around 1997, then to start decreasing; stratospheric BrO has
monoxide
(BrO) is the
most abundant
inorganic
continued
to increase
by 15%
over the period 1994-2002
Bromine
bromine species during daylight, and therefore it is a good
indicator of –
the The
total amount
of inorganic
present inneeds further study; it makes the
coupling
ozonebromine
 climate
the stratosphere. Displayed here are the yearly averaged slant
recovery of ozone uncertain at present.
columns of BrO measured since 1994, as well as their
associated uncertainties. A linear fit to the data (represented by
the straight solid line) reveals an increase of about 15% of the
stratospheric BrO content over the period 1994-2002. This
– deviation
Findings
been
integrated
Percentage
of the
total
ozone
column
(measured
withWMO
a Dobsonassessments,
spectrophotometer)thus
at Uccle from the mean
increase
is consistent
with
thehave
recent
years'
reported
rates ofin
of theoffirst
tensupporting
years (1972-1982)
of observations,
that it has decreased
by 4%
during Protocol
the past 2 decades. The
and
Kyoto
change
anthropogenic
bromineMontreal
source
gases Protocol
at theshowing
ground,adjustments
here have
been corrected
the influence
of SO2 present in the boundary layer in the 1970s due to coal
as data
wellshown
as with
recently
published forinorganic
bromine
combustion.from stratospheric balloons (e.g., see WMO
measurements
Report Nr. 47 [2003]).
• Policy support
Ozone 6 - 9 August 1997
Air quality and
climate:
reduction
of NOx and VOC emissions with 50%
How has tropospheric O3 changed ?
No emission reduction
• 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
– ofNevertheless
tropospheric
predicted
toatcontinue
Visualisation
episodic peak background
ozone concentrations
over EuropeOon
6, 1997
12 hrs, as
3 isAugust
computed by the
model,
using emissions
of 1997
without
emission
(left) to
and with
to EUROS
increase
in future
(possibly
by up
to 60%
untilreductions
2100), due
50% reductionmajor
of NOxincreases
and VOC in
emissions
in Europe
compared
to increase
1997 (right).
The
O3 a
peak
developing
countries.
This
will
have
concentration positive
is indicated
according
to the bottom colour scale (1 g/m3 O3 = 0.70 ppbv O3).
forcing
on climate.
According to these model simulations, reductions of NOx and VOCs clearly have a positive impact on
the tropospheric O3 peak concentrations. The effect is confirmed by related observations.
Air quality and climate:
Impact 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.
Aerosol mass concentrations at various sites in Europe, for aerosol particles of diameter < 10 m (PM10). The sites for
which the data were provided by UGent are highlighted. The color code indicates different aerosol types: blue= natural
background; green= rural background; yellow= near-city background; red= urban background; black= kerbside (i.e.,
along roads in cities). The data shown are the 5, 25, 50 (median), 75, and 95 % percentiles of 24-hour integrated PM10
mass concentrations, as well as their annual averages. The horizontal lines indicate target upper limit values to be
achieved in the near-future.
– At most near-city, urban background and kerbsite sites,
Belgium will not meet European standards for 2010
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.
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 l’Atmosphère
• Univ. Liège - Groupe Infrarouge de Physique Atmosphérique et
Solaire
• VITO - Remote Sensing and Atmospheric Processes