Climate Forecasting Unit On the North Pacific reduced skill in near-term climate predictions of sea surface temperatures Virginie Guemas With the collaboration.

Climate Forecasting Unit

On the North Pacific reduced skill in near-term climate predictions of

sea surface temperatures

Virginie Guemas

With the collaboration of : Francisco Doblas-Reyes, Fabian Lienert, Hui Du, Yves Soufflet


Francisco J Doblas-Reyes : The Head

Hui Du : Initial perturbations, sea ice

Javier García-Serrano : AMO, African monsoon

Virginie Guemas : Sea ice, North Pacific skill

Fabian Lienert : regionalisation, PDO

Melanie Davis : climate services

Danila Volpi : initialisation techniques

Luis Ricardo Rodrigues : ENSO, statistical models

Aida Pintó : extremes

Muhammad Asif : EC-Earth

Oriol Mula-Valls : system administrator

Domingo Manubens : autosubmit developer

Our focus : Seasonal to decadal prediction

We share, on request :

1) Autosubmit

2) Our decadal hindcasts

3) Monthly sea ice restarts

4) R diagnostic functions

We run on :

1) Marenostrum ( Spain )

2) ECMWF

3) HECTOR ( Scotland )

4) Lindgren ( Sweden )

5) Our local cluster


On the North Pacific reduced skill in near-term climate predictions of

sea surface temperatures

Virginie Guemas

With the collaboration of : Francisco Doblas-Reyes, Fabian Lienert, Hui Du, Yves Soufflet


The climate prediction exercise

Fig. 2 of Meehl et al. (2009, BAMS)


Nov 60 Nov 65 Nov 70 Nov 75 Nov 80 ...

Multi-model ensemble system with coupled initialized GCMs

Model 1 Model 2 Model 3 Model 4 Model 5 Model 6

Leadtime = 10 years

Obs






Obs

Leadtime = 5 years




Leadtime = 2-5 years

Obs







Obs







Obs





CERFACS UKMO IFM-GEOMAR

ECMWF DePreSys EC-Earth

2m atmospheric temperature skillCorrelation modelled and ERA40 T2M. Leadtimes : 2-5 years




Correlation modelled and ERSST SST. Leadtimes : 2-5 years

Sea Surface Temperature skill


Correlation between multi-model ensemble-mean and ERSST SST

Sea Surface Temperature skill




Which major events are missed ?Sea Surface Temperature anomalies (155°E-235°E, 10°N-45°N)


Outline

Links with well-known variability modes ?

Mechanism explaining the 1963 event


Possible cause for the failure of forecasting systems


Outline






Two major warmings in the North Pacific Ocean in

1963 and 1968

Da Silva et al. (1994) turbulent

Da Silva et al. (1994) total

OAFluxes turbulent

ERSST

Sea Surface Temperature anomalies (155-235°E 10-45°N )

Upward surface heat fluxes anomalies (155-235°E 10-45°N )

155-235°E 10-45°N


No links with the main modes of variability

http://www.esrl.noaa.gov/psd/data/climateindices/

Monthly values

12-month running mean


Outline






1963: 3-dimensional structure of the anomaly

Pattern of ERSST anomalies (155-235°E 10-45°N )

NEMOVAR temperature anomaly profile (180-205°E – 35-45°N)°C


1963: advection of the anomaly

Hoevmuller ERSST anomalies ( 35°N-45°N latitude band)

NEMOVAR backward trajectories computed with ARIANE

ARIANE ( http://stockage.univ-brest.fr/~grima/Ariane/)

April 1963November 1960

°C


1963: modulation of the amplitude by mixing

Hoevmuller ERSST anomalies ( 35°N-45°N latitude band) °C

NEMOVAR climatological mixed layer depth ( 35°N-45°N ) m


Outline






1968: 3-dimensional structure of the anomaly

Pattern of ERSST anomalies (155-235°E 10-45°N ) °C

NEMOVAR temperature anomaly profile (170-235°E – 10-35°N)


1968: upward transfer of the anomaly



1968: amplification by the atmosphere forcing

Wind speed anomalies (170-235°E, 10-35°N)

DFS4.3NCEP



Outline






Stratification in the Pacific Ocean

NE

MO

VA

R-C

OM

BIN

EC

ER

FA

CS

IFM

-GE

OM

AR

EC

-Earth

v2

FMA mixed layer depth (density criteria) in m


Conclusion

North Pacific region = region of lowest skill in near-term climate predictions ( 2- 5 years )

Major warm events around 1963 and 1968 missed by every forecasting systems = main cause for the low skill

1963 : heat anomaly advected along the Kuroshio-Oyashio and confined to an increasingly thinnner mixed layer

1968 : deep heat anomaly transferred toward the surface and then amplified by the atmospheric noise

Biases in the Pacific ocean stratification could be responsible for the failure of the forecasting systems


Thanks for your attentionThanks for your attention

[email protected]@ic3.cat

Climate Forecasting Unit On the North Pacific reduced skill in near-term climate predictions of sea surface temperatures Virginie Guemas With the collaboration.

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