Extended Data Fig. 3: The role of external forcing is similar in a N. Pacific sea-surface temperature index.
From: Human emissions drive recent trends in North Pacific climate variations
An index of linearly detrended, spatial-average sea-surface temperatures in the Kuroshio-Oyashio Extension region of the North Pacific is calculated (31° – 36° N, 140° – 165° E; black outline) and regressed on SSTs in observations and models, which shows that the forced signal described in-text is not an artifact of the method we use to calculate the PDO index. a, The detrended, observed KOE sea-surface temperature index (black) compared and the detrended ensemble mean KOE SST index (dark blue) and the normalized, detrended, ensemble mean KOE SST index from the all-forcings simulations (light blue). We normalize the forced KOE index strictly to illustrate the timing of the shifts in both indices; the amplitudes of each timeseries are listed in Extended Data Table 2 and discussed in-text. b, Regression of observed SST (colours) on the observed, detrended, KOE index. c, Regression of forced SST (colours) on the normalized, detrended, forced KOE index.
