Young-Oh Kwon and Clara Deser NCAR Decadal Ocean/Atmosphere Variability in the North Pacific in CCSM2 (Model Years 350-999) Young-Oh Kwon and Clara Deser NCAR 9th Annual CCSM Workshop (July 7-9 2004, Santa Fe, NM)

EOF 1 (22 %) Winter SST Anomalies CCSM2

Winter SST Kuroshio Extension Index

Power Spectrum Winter SST Kuroshio Extension Index 80 10 25 ~40 yr ~16 yr

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

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.

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.

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

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

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

Winter SST KEI and Kuroshio Transport ~40 yr

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

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

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.