REanalysis of the TROpospheric chemical composition over the past 40 years FIRE ENGINE View project FUELMON -remote FUEL break MONitoring for forest fire protection View project
Résumé
REanalysis of the TROpospheric chemical composition over the
past 40 years (RETRO)
Objectives:
• exploit (often under-utilised) existing data sets from ground based stations,
aircraft, and satellite instruments, integrating these into common datasets,
• develop tools for the analysis, interpretation and exploitation of the data,
• formulate recommendations for future measurement strategies,
• assess changes in trace compound emissions and their effect on tropospheric
chemical composition and aerosols, and the associated radiative forcing, over
the past 40 years,
• provide an assessment of uncertainties caused by climate variability,
• evaluate emission control strategies in Europe,
• predict changes over the next 20 years in tropospheric composition, and
radiative forcing through model studies using the emission scenarios defined
for the IPCC 2001 climate assessment,
• analyze the magnitude of intercontinental pollutant transport.
Scientific achievements:
• first detailed, comprehensive and consistent data sets on global emissions
from fossil and biofuel combustion and from open vegetation burning
covering the time period 1960-2000; available as gridded data sets with
0.5°×0.5° and monthly mean resolution,
• first global long-term atmospheric chemistry integrations with several stateof-
the-art models using the ERA-40 meteorological data, the RETRO
emissions and other constrains in a consistent and well-documented manner,
• analysis of key parameters controlling the interannual and seasonal
variability and the longer-term trends in the tropospheric composition related
to ozone and its precursors,
• development of new software tools for the analysis of observational data and
model results; standardisation of model output and data formats and
definition of model evaluation metrics and skill scores,
• development of a comprehensive data base for tropospheric composition
observations with complete metadata definition and a user-friendly interface
for data access,
• multi-model analysis of specific scenarios related to power generation and
the traffic sector in OECD countries,
• contributions to the IPCC 4th assessment report through participation in a
multi-model assessment study coordinated by the ACCENT network of
excellence
Main deliverables:
• gridded data sets of global emissions from 1960 to 2000 (D1-4)
• gridded data sets of simulated concentrations of ozone and ozone precursors
from 1960 to 2000 (D4-3)
• data base of atmospheric observations
report on the RETRO emission inventories (D1-6)
o report on trend analysis based on observational data (D2-3)
o reports on sensitivity studies (D3-2, D3-3 and D3-4)
o report on the long-term reanalysis simulations (D4-4)
o reports on changes in UV and radiative forcing (D5-1 and D5-2)
o analysis of past policy measures including scenario studies (D5-5)
All RETRO deliverables are available on the RETRO ftp server
ftp://ftp.retro.enes.org/pub or via the RETRO web pages http://retro.enes.org.
Socio-economic relevance and policy implications:
Understanding past trends in large-scale air pollution is a key requirement to
formulate future strategies to enhance air quality in Europe and elsewhere. Due to
the scarcity of observational data (particularly for years before 1990), numerical
models are the only way to obtain comprehensive and consistent information on
past trends in tropospheric ozone and related substances. The model simulations
in RETRO also allow for evaluating the impact of important parameters on the
interannual variability of air pollution in Europe. From specific sensitivity studies
the roles of meteorological variability, variability in anthropogenic emissions and
variability in wildland fire emissions could be determined. Scenario calculations
on the impact of certain policy measures to reduce emissions from power
generation or from the traffic sector provide a direct answer to the potential
consequences of the introduction of more stringent air pollution abatement
measures. Due to the effects of intercontinental transport of air pollution, local
measures may not always achieve the expected results. These issues can only be
addressed with comprehensive, well-constrained global model simulations as they
were pioneered in the RETRO project. Several of the tools and methodologies
developed in RETRO are now applied in ongoing projects with a more immediate
policy link (especially the FP6 integrated project GEMS and the multi-model
assessment activity under the auspices of the task force on hemispheric transport
of air pollution).
Conclusions:
• RETRO contributed significant developments to advance the state-of-the-art
in global atmospheric chemistry modelling in terms of new long-term
emissions data and the first comprehensive long-term multi-model
integrations of atmospheric chemistry and transport,
• The RETRO models generally show very good consistency in terms of
interannual variability and trend patterns, but they occasionally differ
significantly in the absolute values of the simulated concentrations of ozone
and its precursors,
• Comparison with observations shows that the RETRO models often capture
the atmospheric variability patterns rather well and that the mean model
generally provides a reasonable description of the chemical state of the
atmosphere. Some exceptions are noted, in particular the absence of an
increasing ozone trend over central Europe in the 1990s which is clearly seen
from measurements at several mountain stations,
• According to the RETRO simulations, summertime boundary layer
concentrations of ozone over Europe increased between 5 and 15 ppb (10-
20%) between 1960 and the year 2000. Further abatement measures in the
traffic sector (introduction of the EURO 5 standard in all OECD countries)
could lead to a reduction of summertime ozone by 8-10%.
• A renewed effort following on the RETRO activities would be highly
desirable in order to further expand the available emission data sets
(inclusion of SO2, aerosol precursors and greenhouse gases and review of
natural emissions), to further investigate the underlying causes for
tropospheric composition change and to include the analysis of feedbacks
between tropospheric ozone, climate change and aerosols.
Dissemination of results:
• more than 30 articles appeared in peer reviewed scientific journals with direct
or indirect contributions from the RETRO project,
• RETRO project results were presented in more than 100 conference
contributions and presentations at international meetings,
• a specific session on “tropospheric trends and variability” was inaugurated at
the EGU General Symposium 2004 and was repeated in 2006 and 2007,
• RETRO emission data sets are being used in several ongoing research
projects (e.g. GEMS and TFHTAP, GREENCYCLES, etc.),
• All RETRO data sets and reports are available on the RETRO ftp server
ftp://ftp.retro.enes.org/pub or via the RETRO web pages at
http://retro.enes.org.
Origine : Fichiers produits par l'(les) auteur(s)
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