Regime-dependent predictability and forecast error spectra of ......v Potential predictability from...
Transcript of Regime-dependent predictability and forecast error spectra of ......v Potential predictability from...
![Page 1: Regime-dependent predictability and forecast error spectra of ......v Potential predictability from mean of EOF1 out to 15 days v Potential predictability from mean of EOF3 out to](https://reader036.fdocuments.in/reader036/viewer/2022081619/60f7f1c58915007231685913/html5/thumbnails/1.jpg)
ì
Regime-dependentpredictabilityandforecasterror
spectraofinitializedforecasts
![Page 2: Regime-dependent predictability and forecast error spectra of ......v Potential predictability from mean of EOF1 out to 15 days v Potential predictability from mean of EOF3 out to](https://reader036.fdocuments.in/reader036/viewer/2022081619/60f7f1c58915007231685913/html5/thumbnails/2.jpg)
Acknowledgements
ì ThankstoLauraFerranti,SusannaCorti,YagaRichter,HannahChristensen
![Page 3: Regime-dependent predictability and forecast error spectra of ......v Potential predictability from mean of EOF1 out to 15 days v Potential predictability from mean of EOF3 out to](https://reader036.fdocuments.in/reader036/viewer/2022081619/60f7f1c58915007231685913/html5/thumbnails/3.jpg)
Regimesinclimate
ì E.g.Vautard1990,KimotoandGhil,1993;Cortietal.1999
ì Identificationofregimesandpreferredtransitions
ì Climatestatisticperspective,oftenexpressedastransitionmatrix
Vautard1990Cortietal.1999 KimotoandGhil,1993
![Page 4: Regime-dependent predictability and forecast error spectra of ......v Potential predictability from mean of EOF1 out to 15 days v Potential predictability from mean of EOF3 out to](https://reader036.fdocuments.in/reader036/viewer/2022081619/60f7f1c58915007231685913/html5/thumbnails/4.jpg)
Flow-DependentVerificationoftheECMWFEnsembleovertheEuro-AtlanticSector
ì ExtendedpredictabilityofstatesthatprojectatinitialtimeonNAO-
ì Initializedforecasts
Ferrantietal.2015
![Page 5: Regime-dependent predictability and forecast error spectra of ......v Potential predictability from mean of EOF1 out to 15 days v Potential predictability from mean of EOF3 out to](https://reader036.fdocuments.in/reader036/viewer/2022081619/60f7f1c58915007231685913/html5/thumbnails/5.jpg)
ExperimentSetup
ì Z500anomaliesì ExtendedWinterOct-Marì NAOregion20:80°N,90°W:40°Eì PNAregion20:85°N,120°E:120°W
ì Potentialpredictabilityindailyoutputof
CESM1.1(Largeensemble)ì 400yearsì Notinitialized!ì PerfectModelScenarioì ProjectontoEOFphasespace
![Page 6: Regime-dependent predictability and forecast error spectra of ......v Potential predictability from mean of EOF1 out to 15 days v Potential predictability from mean of EOF3 out to](https://reader036.fdocuments.in/reader036/viewer/2022081619/60f7f1c58915007231685913/html5/thumbnails/6.jpg)
PacificNorthAmericanPattern
PNA-ì RidgeoverWesternNorthAmericaandtrough
overEasternNorthAmericaì Coldandmoistinthewestì WarmanddryintheSouthEast
PNA+ì RidgeoverWesternNorthAmericaandtrough
overEastersNorthAmericaì Warmanddryinthewestì ColdandwetintheSouthEast
LH
HH
L
![Page 7: Regime-dependent predictability and forecast error spectra of ......v Potential predictability from mean of EOF1 out to 15 days v Potential predictability from mean of EOF3 out to](https://reader036.fdocuments.in/reader036/viewer/2022081619/60f7f1c58915007231685913/html5/thumbnails/7.jpg)
Composites
![Page 8: Regime-dependent predictability and forecast error spectra of ......v Potential predictability from mean of EOF1 out to 15 days v Potential predictability from mean of EOF3 out to](https://reader036.fdocuments.in/reader036/viewer/2022081619/60f7f1c58915007231685913/html5/thumbnails/8.jpg)
EvolutionofstatesinEOFstatespace
![Page 9: Regime-dependent predictability and forecast error spectra of ......v Potential predictability from mean of EOF1 out to 15 days v Potential predictability from mean of EOF3 out to](https://reader036.fdocuments.in/reader036/viewer/2022081619/60f7f1c58915007231685913/html5/thumbnails/9.jpg)
SkillfromMean
ForecastDistributionp
Climatologicaldistributionq
Predictiveskillcomesfromthedifferenceoftheensemblemeanforecasttotheclimatologicalmean
![Page 10: Regime-dependent predictability and forecast error spectra of ......v Potential predictability from mean of EOF1 out to 15 days v Potential predictability from mean of EOF3 out to](https://reader036.fdocuments.in/reader036/viewer/2022081619/60f7f1c58915007231685913/html5/thumbnails/10.jpg)
Evolutionofclustermeans
v PotentialpredictabilityfrommeanofEOF1outto15daysv PotentialpredictabilityfrommeanofEOF3outto30daysv Preferredregimetransitionsleadtodeviationsfromclimatology(e.g.withmax
atday7inEOF2)
![Page 11: Regime-dependent predictability and forecast error spectra of ......v Potential predictability from mean of EOF1 out to 15 days v Potential predictability from mean of EOF3 out to](https://reader036.fdocuments.in/reader036/viewer/2022081619/60f7f1c58915007231685913/html5/thumbnails/11.jpg)
Skillfromspread
ForecastDistributionp
Climatologicaldistributionq
Predictiveskillcomesfromthedifferenceoftheensemblemeanforecasttotheclimatologicalmean
ForecastDistributionp
Climatologicaldistributionq
Predictiveskillcomesfromdifferenceoftheforecastvariancewiththeclimatologicalvariance
x
![Page 12: Regime-dependent predictability and forecast error spectra of ......v Potential predictability from mean of EOF1 out to 15 days v Potential predictability from mean of EOF3 out to](https://reader036.fdocuments.in/reader036/viewer/2022081619/60f7f1c58915007231685913/html5/thumbnails/12.jpg)
Evolutionofclustervariance
v PotentialpredictabilityfromvarianceofEOF1outto6daysforPNA+(8forPNA-);v PotentialpredictabilityfromvarianceofEOF2/EOF3outto12daysforPNA-v PreferredregimetransitionsleadtodecreaseinvarianceofEOF2/EOF3forthefirst
fewdays
![Page 13: Regime-dependent predictability and forecast error spectra of ......v Potential predictability from mean of EOF1 out to 15 days v Potential predictability from mean of EOF3 out to](https://reader036.fdocuments.in/reader036/viewer/2022081619/60f7f1c58915007231685913/html5/thumbnails/13.jpg)
Evolutionofclustervariance
v PotentialpredictabilityfromvarianceofEOF1outto6daysforPNA+(8forPNA-);v PotentialpredictabilityfromvarianceofEOF2/EOF3outto12daysforPNA-v PreferredregimetransitionsleadtodecreaseinvarianceofEOF2/EOF3forthefirst
fewdays
=>Relativeentropy
![Page 14: Regime-dependent predictability and forecast error spectra of ......v Potential predictability from mean of EOF1 out to 15 days v Potential predictability from mean of EOF3 out to](https://reader036.fdocuments.in/reader036/viewer/2022081619/60f7f1c58915007231685913/html5/thumbnails/14.jpg)
RelativeentropyR(KullbackLeiblerdistance)• Climatologicaldistributionq,Forecastdistributionp• AsforlongleadtimesapproachesR->0• E.g.Kleeman2002
• Assuming1DGaussians
![Page 15: Regime-dependent predictability and forecast error spectra of ......v Potential predictability from mean of EOF1 out to 15 days v Potential predictability from mean of EOF3 out to](https://reader036.fdocuments.in/reader036/viewer/2022081619/60f7f1c58915007231685913/html5/thumbnails/15.jpg)
Evolutionofclustermean
![Page 16: Regime-dependent predictability and forecast error spectra of ......v Potential predictability from mean of EOF1 out to 15 days v Potential predictability from mean of EOF3 out to](https://reader036.fdocuments.in/reader036/viewer/2022081619/60f7f1c58915007231685913/html5/thumbnails/16.jpg)
Evolutionofclustervariance
Persistence
![Page 17: Regime-dependent predictability and forecast error spectra of ......v Potential predictability from mean of EOF1 out to 15 days v Potential predictability from mean of EOF3 out to](https://reader036.fdocuments.in/reader036/viewer/2022081619/60f7f1c58915007231685913/html5/thumbnails/17.jpg)
![Page 18: Regime-dependent predictability and forecast error spectra of ......v Potential predictability from mean of EOF1 out to 15 days v Potential predictability from mean of EOF3 out to](https://reader036.fdocuments.in/reader036/viewer/2022081619/60f7f1c58915007231685913/html5/thumbnails/18.jpg)
![Page 19: Regime-dependent predictability and forecast error spectra of ......v Potential predictability from mean of EOF1 out to 15 days v Potential predictability from mean of EOF3 out to](https://reader036.fdocuments.in/reader036/viewer/2022081619/60f7f1c58915007231685913/html5/thumbnails/19.jpg)
Nonlinearphase-spacedynamics
BranstatorandBerner,2007
Zonalandblockregimes
![Page 20: Regime-dependent predictability and forecast error spectra of ......v Potential predictability from mean of EOF1 out to 15 days v Potential predictability from mean of EOF3 out to](https://reader036.fdocuments.in/reader036/viewer/2022081619/60f7f1c58915007231685913/html5/thumbnails/20.jpg)
Evolutionofclustermeans
![Page 21: Regime-dependent predictability and forecast error spectra of ......v Potential predictability from mean of EOF1 out to 15 days v Potential predictability from mean of EOF3 out to](https://reader036.fdocuments.in/reader036/viewer/2022081619/60f7f1c58915007231685913/html5/thumbnails/21.jpg)
Anomalycorrelationinperfectmodelscenario
• ACC=Correlationsbetweenforecastandverifyingobservations
• Here:analogues(excluding>+/-2dfrominitialization)areusedasverifyingobservations
• Conservativeestimate
![Page 22: Regime-dependent predictability and forecast error spectra of ......v Potential predictability from mean of EOF1 out to 15 days v Potential predictability from mean of EOF3 out to](https://reader036.fdocuments.in/reader036/viewer/2022081619/60f7f1c58915007231685913/html5/thumbnails/22.jpg)
ì Extendedpotentialpredictabilityforstatesinitializedin+/-phasesofNAOandPNAby2-3days
ì Preferredregimestransitionsindailydataì Notjuststatisticalconcept,butreflectedasskillofinitialized
forecastsì Morethanpersistence!!
Conclusions
![Page 23: Regime-dependent predictability and forecast error spectra of ......v Potential predictability from mean of EOF1 out to 15 days v Potential predictability from mean of EOF3 out to](https://reader036.fdocuments.in/reader036/viewer/2022081619/60f7f1c58915007231685913/html5/thumbnails/23.jpg)
Futurework
ì Betterphasespace(optimalpersistencepattern?)
ì Sensitivitytoresolutionì Stochasticparameterizationì Otherteleconnections,e.g.ElNino,MJO
![Page 24: Regime-dependent predictability and forecast error spectra of ......v Potential predictability from mean of EOF1 out to 15 days v Potential predictability from mean of EOF3 out to](https://reader036.fdocuments.in/reader036/viewer/2022081619/60f7f1c58915007231685913/html5/thumbnails/24.jpg)
Meansystematicerrorof500hPageopotentialheightfieldsinECMWFIFS
a)
-10
-6
-6
-6
-6
-2
-2
-2
-2
-2
-2
-2
-2
-2
2
2
2
2
2
2
6
66
Z500 Difference eto4-er40 (12-3 1990-2005)
-14-12-10-8-6-4-22468101214b)
-6
-6
-2
-2
-2
-2
-2
-2
2
2
2 2
2
2
2
2
Z500 Difference ezeu-er40 (12-3 1990-2005)
-14-12-10-8-6-4-22468101214
c)
-6 -2
-2
-2
-2
-2
-2
-2
2
2
2
2
2
2
2
2
Z500 Difference eut3-er40 (12-3 1990-2005)
-14-12-10-8-6-4-22468101214d)
-2 -2
-2
-2
-2
-2
-2
-2
2
2
Z500 Difference f8o8-er40 (12-3 1990-2005)
-14-12-10-8-6-4-22468101214
SKEBSLOWRES
• Reductionofz500biasinallsimulationswithmodel-refinement
Berneretal.,2012
HIGHRES
a)
-10-6
-6
-6
-6
-2
-2
-2
-2
-2
-2
-2
-2
-2
2
2
2
2
2
2
6
66
Z500 Difference eto4-er40 (12-3 1990-2005)
-14-12-10-8-6-4-22468101214b)
-6
-6
-2
-2
-2
-2
-2
-2
2
2
2 2
2
2
2
2
Z500 Difference ezeu-er40 (12-3 1990-2005)
-14-12-10-8-6-4-22468101214
c)
-6 -2
-2
-2
-2
-2
-2
-2
2
2
2
2
2
2
2
2
Z500 Difference eut3-er40 (12-3 1990-2005)
-14-12-10-8-6-4-22468101214d)
-2 -2
-2
-2
-2
-2
-2
-2
2
2
Z500 Difference f8o8-er40 (12-3 1990-2005)
-14-12-10-8-6-4-22468101214
![Page 25: Regime-dependent predictability and forecast error spectra of ......v Potential predictability from mean of EOF1 out to 15 days v Potential predictability from mean of EOF3 out to](https://reader036.fdocuments.in/reader036/viewer/2022081619/60f7f1c58915007231685913/html5/thumbnails/25.jpg)
NAOandPNAinCESM
![Page 26: Regime-dependent predictability and forecast error spectra of ......v Potential predictability from mean of EOF1 out to 15 days v Potential predictability from mean of EOF3 out to](https://reader036.fdocuments.in/reader036/viewer/2022081619/60f7f1c58915007231685913/html5/thumbnails/26.jpg)
Berner,Sardeshmukh,Christensen,“OnthedynamicalmechnismsgoverningENSOIrregularity”
ThursdayP-C3-02
Berneretal.,J.Clim.2018
![Page 27: Regime-dependent predictability and forecast error spectra of ......v Potential predictability from mean of EOF1 out to 15 days v Potential predictability from mean of EOF3 out to](https://reader036.fdocuments.in/reader036/viewer/2022081619/60f7f1c58915007231685913/html5/thumbnails/27.jpg)
EOFs