Fig. 1

Time series of Nino3.4 index and the PDO index. Dashed lines indicate the ±0.5℃ thresholds for ENSO events"

Tab. 1

El Niño and La Niña events in the different PDO phases"

Fig. 2

Skewness of SSTA in (a) positive and (b) negative phases of the PDO. The white area is the missing data area"

Fig. 3

Composites of mature phase mean SST anomaly (units: °C) over the tropical Pacific during (a) El Niño event and (c) La Niña event and (e) El Niño event+La Niña event in positive PDO phase and (b) El Niño event and (d) La Niña event and (e) El Niño event+La Niña event in negative PDO phase. The white area is the missing data area"

Fig. 4

Time series of the subsurface NDH and Nino3.4 SSTA for 1959—2011"

Fig. 5

(a) The Long-term mean of the NDH averaged over 1°S—1°N in the positive PDO phase and its (b) zonal, (c) meridional, and (d) vertical components, (e) the long-term mean of the NDH averaged over 1°S—1°N in the negative PDO phase and its (f) zonal, (g) meridional, and (h) vertical components. The thick black line are the climatological 20℃ isotherm"

Fig. 6

Scatter plots of LDH and NDH in the (a) positive PDO phase and in the (b) negative PDO phase"

Fig. 7

Longitude-depth sections of the skewness of the temperature anomaly averaged over 1°S—1°N in (a) positive PDO phase and (b) negative PDO phase"

Fig. 8

Time-longitude composite of SSTA (5°S—5°N) of El Niño in (a) positive PDO phase and (c) negative PDO phase, SSTA (5°S—5°N) of La Niña over in (e) positive PDO phase and (g) negative PDO phase, SubTA (1°S—1°N and 50~150 m depth) of El Niño in (b) positive PDO phase and (d) negative PDO phase and SubTA (1°S—1°N and 50~150 m depth) of La Niña in (f) positive PDO phase and (h) negative PDO phase"

Fig. 9

The subsurface temperature tendency terms (left) - (right) along the x-axis: the temperature tendency, the subsurface NDH, and the subsurface LDH in (a) positive PDO phase and (b) negative PDO phase. The subsurface temperature tendency terms (left)-(right) along the x-axis: the subsurface NDHx, the subsurface NDHy, and the subsurface NDHz in (c) positive PDO phase and (d) negative PDO phase. All the terms are averaged over the far eastern equatorial Pacific (1°N—1°S, 130—90°W and 50~150 m depth) for the developing period of the composite ENSO events"

Fig. 10

Longitude-depth structures between 1°S and 1°N in the development period of the composite ENSO events in different PDO phases. Anomalies of the (a, d, g, j) temperature (°C), (b, e, h, k) zonal current (m·s-1) and (c, f, i, l) NDHx"