Decadal variability
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Transcript of Decadal variability
Decadal variabilityDecadal variability
Qiu and Chen, 2005
KE is characterized by the presence of two quasi-stationary meanders at 144° and 155°E
Up and downstream jets
Decadal variabilityDecadal variability
Qiu and Chen, 2005
Can the observed decadal variability be explained by the forcing of the large-scale wind stress field?
Decadal variabilityDecadal variability
• 1 ½ layer reduced gravity model for the ocean response to surface wind forcing
Data from OFESData from OFES
SSH EOF’s 1 & 2SSH EOF’s 1 & 2
OFES
ROMS
SSH PCs 1 & 2 from OFESSSH PCs 1 & 2 from OFES
Regression maps SSHRegression maps SSH
Regression maps SSTRegression maps SST
Regression maps (lags)Regression maps (lags)
SSH – PC 1
Regression maps (lags)Regression maps (lags)
SST – PC 1
Regression maps (lags)Regression maps (lags)
SSH – PC 2Propagation of SSH anomalies in the SW direction
Regression maps (lags)Regression maps (lags)
SST – PC 2
Zonal SSH EOFsZonal SSH EOFs SSH average zonally between 142°E-180°
EOF 1: 52.98%
EOF 2: 17.96%
Taguchi et al, 2007
Taguchi et al, 2007
The second mode tracks very well with the strength of the KE jet
The first mode represents a north-south shift of the KE jet
Lag correlation betweenNPGO index and Kuroshio zonal PC2
Strength of Kuroshio(Taguchi et al. 2007; Qiu et al., 2005)Isolated as the zonal PC 2 of SSHa field between142-180E
NCEP wind stress curl vs NPGONCEP wind stress curl vs NPGO
NCEP wind stress curl vs PDONCEP wind stress curl vs PDO
KOE SST indexKOE SST indexQiu et al, 2007
GFDL SSHA EOFsGFDL SSHA EOFs
Regression maps (lags)Regression maps (lags) SSH – PC 2
Zonal modes of KOEZonal modes of KOE