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Hindcasting Europe’s climate – A user perspective
Thomas Klein
European Environment Agency, Copenhagen, Denmark. thomas.klein@eea.europa.eu
1. Needs
There is a general need for a consistent historical European
coverage of climate data to support water, ecosystems and
climate change-related integrated assessments, supporting
EU policies, including the 6th Environment Action Plan, and
complementing the GMES initiative with high quality and
high resolution information on the physical state and past
trends of the climate.
From an EEA perspective, the availability of sound and
detailed European climate monitoring information is
essential. In 2008, the EEA in partnership with the Joint
Research Centre and World Health Organisation Europe
produced the report “Impacts of Europe’s changing climate”
based on more than 40 indicators covering physical,
biological and health impacts (EEA, 2008). The report
shows widespread and increasing changes associated with
climate change outside the most conservative estimates from
the IPCC 2007 report.
However, the report also identifies data gaps such as the lack
of consistent European data at the spatio-temporal resolution
required for regional and local assessments. More detailed
and quantitative, tailor-made information are especially
needed for regional climate impact assessments and the
development of cost-effective adaptation strategies.
2. The EURRA concept
The needs and data gaps outlined above are consistent with
earlier findings which led to discussions between EEA and
ECMWF and a workshop (ECMWF, 2005) with
representatives of EEA, ECMWF and European National
Meteorological and Hydrological Services about the concept
of a high-resolution Europe-wide reanalysis, nested into
climate quality global reanalyses. Such a European Regional
Reanalysis (EURRA) could provide multi-decadal
information on variables describing the state of the
atmosphere, coastal ocean, snow cover and land surfaces
(including vegetation and soil moisture).
European regional-scale high-resolution reanalysis requires
basically three major components:
• A global-scale reanalysis system providing
boundary fields for the regional system;
• A regional reanalysis system, together with
additional downscaling techniques for the
provision of very high-resolution information for
specific surface and near-surface variables;
• Observational databases for space-based and
terrestrial information to be assimilated.
Designing and building reusable European capacity
consisting of the above components is essential to allow for
gradual improvements of data quality and resolution in an
iterative process. Updates of data sets can be performed
when justified by sufficient improvements of system
components, computational power and/or by the availability
of better/more observational data in the input databases.
considering also the wider perspective of a GMES climate
change service (EEA, 2009). The meeting was attended by
the European Commission (DG ENV, DG JRC, DG
RTD), ECMWF, EUMETNET, ESA, EUMETSAT, EEA,
GEO and GCOS representatives as well as several country
representatives. Confirming the need for consistent longterm
data series with high quality and high resolution
information on both basic essential climate variables as
well as climate change indicators of impact and
vulnerability, the meeting also identified the EURRA idea
as a feasible way to address the requirements. In
particular, EURRA is expected to serve many specific
demands at European and local level, regarding indicators
e.g. EEA/JRC/WHO report, the Commission’s green
paper and white paper on climate change, impacts
assessments and adaptation measures, assessment of
ecosystem services, hydrological applications etc.
At this stage, EURRA is still a concept, developed in
response to evolving user needs which will need to be
refined in an ongoing process. Moving from concept to
project will require taking into account a number of
project demands, such as the need for integration of large
amounts of physical and socio-economic data, integrating
space and in-situ, data discovery and recovery and high
computer processing capacity. In addition to the technical
requirements, EURRA will need a huge organizational
effort, involvement of many potential actors, funding for
capacity building and operation (e.g. through existing
European funding mechanisms), access to observational
data and a coherent dialogue and cooperation between data
providers and users.
The next steps of the EURRA initiative will include a
further consolidation of user requirements, identification
of funding options, and, in particular, the communication
and promotion of the EURRA concept in forthcoming
workshops. It will also be crucial to learn from existing
reanalysis experiences, including both global (e.g., ERA-
40/ERA-Interim, NCEP/NCAR, JRA, ACRE) and
regional (e.g., North American Regional Reanalysis, the
Arctic System Reanalysis or the BALTEX Regional
Reanalysis) reanalysis initiatives.
References
ECMWF, 2005: http://www.ecmwf.int/newsevents/
meetings/workshops/2005/EURRA/index.html.
EEA, 2008: Impacts of Europe’s changing climate – 2008
indicator-based assessment. European Environment
Agency, Copenhagen.
EEA, 2009: http://eea.eionet.europa.eu/Public/irc/eionetcircle/gmes/library?l=/eurra.
3. Outlook
In early 2009, the EEA held an expert meeting on climate
information services based on atmospheric reanalyses,