Transcript On climate models and climate simulations

RT3, Formulation of very high
resolution Regional Climate Model
Ensembles for Europe
J.H. Christensen (DMI)
M. Rummukainen (SMHI)
B. van den Hurk (KNMI)
DMI, SMHI, KNMI, ICTP, METO-HC, CNRM, GKSS, MPIMET,
UCLM, INM, met.no, CUNI, CHMI
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Overall aim of RT3
• RT3 has the responsibility for providing
improved climate model tools developed in
the context of regional models, but
contributing to high-resolution modelling in
general, first at spatial scales of 50 km at a
European-wide scale within ENSEMBLES
and later also at a resolution of 20km for
specified sub-regions.
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RT3 links to other RTs
• (Output: specify need of GCM-data, to RT1/RT2A)
• Input: GCM data, from RT1/RT2A
• Input: Additional evaluation data, from RT5
• Output: An RCM-ensemble system, to RT2B
• Input: RCM runs of GCM-”controls”, from RT2B
• (Input: impact study requirements, from RT6)
• Output: RCM climate change scenarios for a nonEuropean region
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RT3 models and simulations
• DMI (HIRHAM), SMHI (RCA), KNMI (RACMO),
ICTP (RegCM), METO-HC (HadRM),
CNRM (ALADIN), GKSS (CLM), MPIMET (REMO),
UCM (PROMES), INM (RCA or UM),
met.no (HIRHAM), CUNI& CHMI (ALADIN)
• Regionalisation of ERA-40 at ~50 km (WP3.1)
• Regionalisation of ERA-40 at ~20 km (WP3.1)
• (GCM-driven RCM simulations done in RT2B)
• Simulations for a non-European region (WP3.5)
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RT3, Workpackages
• WP3.1: Creation of an RCM ensemble for ERA-40
• WP3.2: Design and calibration of procedure to create
probabilistic regional climate scenarios
• WP3.3: Design of ensemble strategy
• WP3.4: A comparative analysis of RCM ensemble
•
simulations of present-day using GCM boundary
conditions
WP3.5: RCM-ensemble simulation for non-European
areas
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RT3/WP3.1: Creation of an RCM
ensemble for ERA-40
• State-of-the-art RCM simulations at ~50km.
• Simulations with evaluated/improved RCMs at ~20 km.
• With some models, assess the role of land use and
•
irrigation changes with experiments with and without
such prescribed changes. (A possible link with RT7?)
Link the evaluation of the simulations with RT5
activities, which will provide new high-resolution datasets.
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RT3/WP3.2: Design and calibration of
procedure to create probabilistic regional
climate scenarios
• Techniques for generation of probabilistic regional
•
•
scale predictions. (A regional counterpart to RT1
WP1.6.)
Arrive at a basis for the weighting of individual
ensemble members, to be further refined in WP3.4.
Calculation of model weights will be introduced for
the ensemble of models to be used in prediction
mode, i.e. for use in RT2B.
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RT3/WP3.3: Design of ensemble strategy
• Design the strategy including selection of members
•
based on (GCM) boundary conditions, and model
formulation.
Assign a desired number of RCM-GCM combinations
to provide an "optimal" probabilistic future climate
scenario, in collaboration with RT2a.
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RT3/WP3.4: A comparative analysis of
RCM ensemble simulations of presentday using GCM boundary conditions
• Weighting procedure (WP3.2) based on ERA-40
driven RCMs applied to GCM-control driven RCMs
• Modifications to the procedure to account for GCM•
•
biases developed to allow weighting for RCM
downscaling GCM predictions
Evaluation of the modified procedure
Co-ordinating with RT2B, a strategy and size for the
20km RCM ensemble will be recommended
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RT3/WP3.5: RCM-ensemble simulation
for non-European areas
• Objectives:
• Test RCMs for non-European regions, esp. tropics
• Study the effects of anthropogenic forcings (e.g. land use change,
atmospheric aerosols) in tropical regions
• RCM climate change scenarios for a non-European region
• Possible regions: Sahel, equatorial Africa (West Africa, cf.
AMMA), Amazon Basin, South Asia monsoon region
• Research steps:
• Perfect boundary condition experiments
• Sensitivity experiments (land-use change, aerosols)
• Scenario simulations
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