1. Young-Oh Kwon and Clara Deser NCAR
Decadal Ocean/Atmosphere Variability in the North Pacific in CCSM2 (Model Years )
Young-Oh Kwon and Clara Deser
NCAR
9th Annual CCSM Workshop (July , Santa Fe, NM)

2. EOF 1 (22 %) Winter SST Anomalies CCSM2

3. Winter SST Kuroshio Extension Index

4. Power Spectrum Winter SST Kuroshio Extension Index80 10 25
~40 yr
~16 yr

5. Qnet and Precipitation in the Kuroshio Extension
SST
Local Qnet
SST
Local Precipitation

6. Correlation between Winter SST KEI and Indices at Other Depths
Band Pass Filtered : 10 – 25 yrs
Band-Pass Filtered : 25 – 80 yrs
Contour interval : 0.1
Shaded areas are significant at 95 % C.L.

7. Correlation between Winter SST KEI and Temperature on the Section along 40 °N
Band Pass Filtered : 10 – 25 yrs
Contour interval : 0.1
Shaded areas are significant at 95 % C.L.

8. Winter Temperature Anomaly at 500 m
Contour interval : 0.2 °C

9. SST, Qnet and Precipitation along 40 °N
Contour intervals : 0.5 °C, 20 W/m2, 0.5 mm/day

10. Winter SST KEI and Position of the Kuroshio
Kuroshio Position
~30 yr

11. Winter SST KEI and Kuroshio Transport
~40 yr

12. Observed Winter SST in Kuroshio Extension (Reynolds SST : 1901-2000)
~20 yr

13. Observed Winter SST Anomaly along 40 °N
Band Pass Filtered : 7 – 15 yrs
Band-Pass Filtered : 15 – 25 yrs
Contour interval : 0.2 °C

14. Summary
Robust decadal (~16 years) and interdecadal (~40 years) variability in Kuroshio Extension.
SST, precipitation, surface heat flux, and subsurface temperature.
Ocean dynamics likely play an active role.
Anomaly penetrating down to 1000 m.
Propagating with the Kuroshio Extension.
Heat flux and precipitation responding to SST anomaly.
Anomalous Ekman heat transport acts as a positive feedback response to the SST anomalies.
Similar spectral peaks in Kuroshio transport and position.
Weak atmospheric response.
Some resemblance to Nature.