Post on 04-Jan-2016
transcript
Decadal predictability of winter SST in the Nordic Seas and Barents Sea
in three CMIP5 models
NACLIM ANNUAL MEETING, OCTOBER 14, 2014 BERLIN
H. R. Langehaug, K. Lohmann, T. Eldevik, D. Matei, Y. Gao
The research leading to these results has received funding from:
RCN-EPOCASAEnhancing seasonal-to-decadal Prediction Of Climate for the North Atlantic Sector and Arctic
EU-NACLIMNorth Atlantic climate
Main goal Assessment of decadal predictability wrt SST (winter) What do we expect from the models in this particular region?
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Nordic Seas
Barents Sea
Region of interest
Map based on NASA Worldwind-globe
The region of interest has not been investigated in detail before wrt hindcast prediction experiments in CMIP5
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Outline
› Introduction of the three models› How is the model initialized?
› What is the surface condition compared to HadISST?
› How well do the hindcasts reproduce the observed SST changes in the Atlantic domain?
› Hindcasts are compared with non-initialized runs and the persistence forecast
› Are there specific regions with high predictive skill compared to the rest of the region?
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Nordic Seas
Barents Sea
Map based on NASA Worldwind-globe
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Variance in winter SST in the period 1961-2010
HadISST MPI-ESM-LR
mean SST
MPI-ESM-LR
• Anomaly initialization• 3D assimilation of T & S from ocean reanalysis
initialized every fifth year
Variance in winter SST in the period 1961-2010
HadISST CNRM-CM5
mean SST
CNRM-CM5
• Full-field initialization Correct for the drift• 3D assimilation of T & S from ocean reanalysis
Variance in winter SST in the period 1961-2010
HadISST IPSL-CM5
IPSL-CM5
• Anomaly initialization• SST assimilation, where sea ice concentration is less than 50%
mean SST
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Assessment of decadal predictability wrt winter SST
Time (years) after initialization
Lead time = 1-3 yrsPersistence: HadISST is correlated with itself with a time lag of 1-3 yrs
Hindcast CMIP5 model
Non-initialized CMIP5 model hindcast
non-initialized
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MPI-ESM-LR
CNRM-CM5
IPSL-CM5
hindcast
non-initializedHow well do the models reproduce the observed SST changes in the Atlantic domain?
. Significant correlation
MPI-ESM-LR
. Significant correlation
. Significant correlation
. Significant correlation
. Significant correlation
. Significant correlation
CNRM-CM5
. Significant correlation
. Significant correlation
. Significant correlation
. Significant correlation
. Significant correlation
IPSL-CM5
. Significant correlation
. Significant correlation
. Significant correlation
. Significant correlation
Summary
› Introduction of the three models: similarities/differences?
› How well do the hindcasts reproduce the observed SST changes?
› Local and remote influence on the prediction skill?
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Barents Sea
MPI-ESM-LR and CNRM-CM5 most similar to observations in terms of SST variance
MPI-ESM-LR