Fig. 3

a Lagged regressions of zonally averaged OLR anomaly of 90°–150°E with respect to that at the equator for summers with PC1 > 0.5; b Same as a, but for summers with PC1 < −0.5. The OLR anomaly value corresponds to one standard deviation of that at the equator. The contour interval is 1 W m−2. The zero contour is omitted. c Difference of composites of May–September averaged OLR between positive PC1 and negative PC1. The contour interval is 2 W m−2. Contours for positive values are in read, whereas those for negative values are in blue. The zero contour is omitted. The shaded areas indicate that the value is different from zero at a significance level of 0.05 according to a Student’s t-test