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DEMETER Taiwan, 25-27 October 2003
Development of a
European Multi-Model Ensemble Systemfor
Seasonal to Interannual Prediction
DEMETER
Noel Keenlyside, Institute für Meereskunde, University of Kiel
Tim Palmer, Renate Hagedorn, and Francisco Doblas-Reyes
European Centre for Medium-Range Weather Forecasts (ECMWF)
DEMETER Taiwan, 25-27 October 2003
Predictability
is a nonlinear system
Since is a nonlinear function of
( )
dXF X
dtd X dF
X J Xdt dXF X
J J X
DEMETER Taiwan, 25-27 October 2003
Perturbed parameters
Stochastic physics
Nonlinear dynamical systems for subgrid-motions (e.g. 2D cloud-resolving models, cellular automata)
Singular vectors
Multi-model ensembles
Possible approaches to representation of model error
DEMETER Taiwan, 25-27 October 2003
Multi-model ensemble system
Partner Atmosphere Ocean
ECMWF IFS HOPE
LODYC IFS OPA 8.3
CNRM ARPEGE OPA 8.1
CERFACS ARPEGE OPA 8.3
INGV ECHAM-4 OPA 8.2
MPI ECHAM-5 MPI-OM1
UKMO HadCM3 HadCM3
• DEMETER system: 7 coupled global circulation models
• Hindcast production for: 1987-1999 (1958-2001)
9 member ensembles
ERA-40 initial conditions
SST and wind perturbations
4 start dates per year
6 months hindcasts
DEMETER Taiwan, 25-27 October 2003
Conceptual background (deterministic view)
SST, Tropics, 1987
verification
SST, Tropics, 1988
MSLP, Tropics, 1988
DEMETER Taiwan, 25-27 October 2003
ACC: SST Tropics
DEMETER Taiwan, 25-27 October 2003
Conceptual background (probabilistic view)
SST, Tropics, 1987
MSLP, Tropics, 1988
DEMETER Taiwan, 25-27 October 2003
Reliability: 2m-Temp.>0
0.0490.9020.147
0.0580.9040.151
0.0990.9230.176
-0.007 0.886 0.107
-0.055 0.838 0.107
0.0680.9030.164
0.222 0.994 0.227
0.0750.9210.153
DEMETER Taiwan, 25-27 October 2003
Reliability: 2m-Temp.>0
single-model (54 members)
multi-model
0.222 0.994 0.227
0.170 0.959 0.211
DEMETER Taiwan, 25-27 October 2003
Reliability: 2m-Temp.>0
-0.099 0.859 0.041
-0.126 0.850 0.024
-0.016 0.925 0.059
-0.149 0.816 0.035
-0.099 0.861 0.040
-0.075 0.891 0.034
0.061 0.983 0.078
-0.094 0.882 0.024
DEMETER Taiwan, 25-27 October 2003
Impact of ensemble size
DEMETER Taiwan, 25-27 October 2003
Impact of number of models (members)
Multi-model realizationsSingle-model realizations
DEMETER Taiwan, 25-27 October 2003
SOI-Index: 1 month lead (DJF)
Multi-Model
CERFACS
CNRM ECMWF INGV LODYC MPI UKMO
Correlation
0.94 0.93 0.93 0.84 0.92 0.95 0.86 0.94
RPSS 0.70 0.67 0.62 0.44 0.63 0.74 0.38 0.74
DEMETER Taiwan, 25-27 October 2003
NAO-Index: 1 month lead (DJF)
Multi-Model
CERFACS
CNRMECMW
FINGV LODYC MPI UKMO
Correlation
0.68 0.48 0.44 0.43 0.37 0.49 0.23 0.31
RPSS 0.24 0.15 0.17 0.21 0.07 0.19 0.08 0.09
DEMETER Taiwan, 25-27 October 2003
Tropical Cyclone FrequencyLinear correlation of the tropical cyclone
frequency
By F. Vitart ([email protected])
1st May1st August
1st November
DEMETER Taiwan, 25-27 October 2003
Verification
• Bias
• Indices
• Deterministic Scores
• Probabilistic Scores
• Single vs. multi-model
http://www.ecmwf.int/research/demeter/verification
• 54-single vs. multi-model
• Ocean diagnostics
DEMETER Taiwan, 25-27 October 2003
Verification
Start date
Lead timeParameter
Model
DEMETER Taiwan, 25-27 October 2003
http://data.ecmwf.int/data
Retrieve NetCDF
Period # Years
ECMWF 1958 - 2001
44
CNRM 1958 – 2001
44
UKMO 1959 – 2001
43
MPI 1969 – 2001
33
INGV 1973 – 2001
29
LODYC 1974 – 2001
28
CERFACS 1980 – 2001
22
DEMETER Taiwan, 25-27 October 2003
End-user modelling
• DEMETER ensemble hindcasts input for health application (malaria model) agriculture application (crop model)
• Basic idea: explore utility of DEMETER hindcasts give range of uncertainty
• Main problems: sparse data to validate malaria in Africa need of downscaled data
DEMETER Taiwan, 25-27 October 2003
Multi-Model
CERFACS
CNRMECMW
FINGV LODYC MPI UKMO
Correlation
0.50 0.51 0.52 0.34 0.35 0.29 0.03 0.36
RPSS 0.30 0.23 0.23 0.24 0.27 0.26 -0.25 -0.01
Malaria predictions (0º,35ºE)ERA-40 Multi-Model: Terciles Ens-mean
DEMETER Taiwan, 25-27 October 2003
Crop growth monitoring system
Crop Growth Indicator
Jan Feb Aug
Meteo data
Yield
Statistical model
Meteo data ERA / DEMETER data
DEMETER Taiwan, 25-27 October 2003
Wheat yield predictionsusing downscaled DEMETER multi-model
dataFrance Germany
Denmark Greece
DEMETER Taiwan, 25-27 October 2003
Validation of seasonal forecast presented at
European Research FP6-conference, Brussels 2002
Risk of cold / warm winter 2002/03Risk of wet / dry winter 2002/03
DEMETER Taiwan, 25-27 October 2003
Summary• DEMETER multi-model hindcasts data set: 22-44 years available for 7 models (1958 – 2001)
Extensive diagnostics and data publicly available
• Applications: end-to-end systems for seasonal prediction -> actual value
feasibility of skilful predictions: malaria incidence, crop yield
• Multi-model improves over single-model ensembles: main improvement due to reliability
skill also improves because of increase in resolution
• The future: EU-funded ENSEMBLES project (starts April 2004)
DEMETER Taiwan, 25-27 October 2003
Potential Economic Value
Anom > 0.43
Anom > 0
DEMETER Taiwan, 25-27 October 2003
The DEMETER methodology is also being used to study the changing risk of flood
as a result of man's impact on climate
Control Greenhouse
enhanced risk of flooding
Palmer & Räisänen,
Nature (2002)
DEMETER Taiwan, 25-27 October 2003
tourismenergy
Towards the new FP-6 Project ENSEMBLES
agriculture
aid relief
health
• Integrated prediction system for time scales from
seasons to decades and beyond
• Greater diversity of applications
• Incorporation of the whole earth system
• Assessment of reliability of model system used for scenario runs
DEMETER Taiwan, 25-27 October 2003
Tropical Cyclone FrequencyTropical storm number for the tropical Atlantic
(JJASO)
By F. Vitart ([email protected])
Verification
Multi-model
DEMETER Taiwan, 25-27 October 2003
DEMETER MM-Results: NAO-Index (DJF)
7 models: 1987-1999 (13y)
3 models: 1959 - 2001 (43y)