Fig. 1

EOF modes of FMA precipitation anomaly over the eastern tropical Pacific and the relationships between PCs and concurrent ENSO. Regressions of precipitation (mm·d-1; shading), SST (contour at interval of 0.2℃, zero contour thickened and negative dashed), and surface wind velocity (m·s-1; vector) against (a) the standardized PC1 (54% variance) and (b) the standardized PC2 (20% variance), blue (red) arrows indicate westerly (easterly) wind anomalies. Standardized PCs and concurrent ENSO indices are plotted in (c) and (d), and correlations between standardized PCs and concurrent ENSO indices are plotted in (e)"

Tab. 1

CMIP5 models used in this study"

Fig. 2

First EOF mode of FMA precipitation anomaly over the eastern tropical Pacific in CMIP5 models. Regressions of precipitation (mm·d-1; shading), SST (contour at interval of 0.2℃, zero contour thickened and negative dashed), and surface wind velocity (m·s-1; vector) against the concurrent standardized PC1, blue (red) arrows indicate westerly (easterly) wind anomalies. The skillscore of EPID mode, model name and variance are marked at the bottom left, bottom and bottom right of each subgraph, respectively"

Fig. 3

Same as Fig. 2, except for the second EOF mode of FMA precipitation anomaly over the eastern tropical Pacific in CMIP5 models."

Fig. 4

Taylor diagram of EPID mode in CMIP5 models and observations in FMA OBS: Observation; MME: multi-model ensemble"

Fig. 5

Climatology of SST (℃; contour), precipitation (mm·d-1; shading) and surface wind velocity (m·s-1; vector) in FMA: (a) Observations; (b) in group 1; (c) in group 2; and (d) in group 3"

Fig. 6

First EOF mode of precipitation anomaly over the eastern tropical Pacific after seasonal adjustment in CMIP5 models. Regressions of precipitation (mm·d-1; shading), SST (contour at interval of 0.2℃, zero contour thickened and negative dashed), and surface wind velocity (m·s-1; vector) against the concurrent standardized PC1, blue (red) arrows indicate westerly (easterly) wind anomalies. The season, model name and variance are marked at the bottom left, bottom and bottom right of each subgraph, respectively DJF: December-January-February; JFM: January-February-March; FMA: February-March-April; MAM: March-April-May; AMJ: April-May-June; MME: multi-model ensemble"

Fig. 7

Same as Fig. 6, except for the second EOF mode of precipitation anomaly over the eastern tropical Pacific after seasonal adjustment in CMIP5 models."

Fig. 8

Taylor diagram of EPID mode in CMIP5 models and observations after seasonal adjustment OBS: Observation; MME: multi-model ensemble"

Fig. 9

Multi-model ensemble mean climatology of SST (℃; contour), precipitation (mm·d-1; shading) and surface wind velocity (m·s-1; vector): (a) during FMA; (b) for seasonal adjustment; (c) in group 4; and (d) in group 5"

Fig. 10

Evolution of second EOF mode of precipitation anomaly over the eastern tropical Pacific after seasonal adjustment in CMIP5 models. Regressions of precipitation (mm·d-1; shading), SST (contour at interval of 0.2℃, zero contour thickened and negative dashed), and surface wind velocity (m·s-1; vector) with increased (decreased) speed in blue (red). All zonally averaged in 140°-80°W upon the standardized PC2 of precipitation EOF are shown as a function of calendar month and latitude. The brown dashed line is the centroid of tropical climatological precipitation. The black vertical line is the central month of EPID after seasonal adjustment. The number on the horizontal axis is month, 1 in bracket indicates the current year of the month after seasonal adjustment, and 0 represents the previous year."

Fig. 11

The relationships between EOF modes of precipitation anomaly over the eastern tropical Pacific and concurrent ENSO in group 4 (a) Correlation coefficient histogram of PC in EOF results and concurrent ENSO, dashed lines mean the 95% confidence level. (b)Scatterplots with correlation coefficients of PC1 and E-index and spatial correlation coefficients of EOF1 and precipitation anomaly regression field of E-index. (c)Scatterplots with correlation coefficients of PC2 and C-index and spatial correlation coefficients of EPID mode and precipitation anomaly regression field of C-index b(PC1, Pre): EOF first mode; b(E-index, Pre): regression field of E-index and concurrent precipitation anomaly over the eastern tropical Pacific; b(PC2, Pre)EPID mode; b(C-index, Pre): regression field of C-index and concurrent precipitation anomaly over the eastern tropical Pacific OBS: observation; A: IPSL-CM5B-LR; B: MIROC-ESM; C: MIROC-ESM-CHEM; D: INMCM4; E: ACCESS1-3; F: ACCESS1-0; G: GFDL-CM3; H: GFDL-ESM2G; I: CanESM2; J: MPI-ESM-P; K: MIROC5; L: MPI-ESM-LR; M: CMCC-CM"