Figure 6. (a) and (b) present the second EOF (φ2) of the gridded, tide gauge obtained, sea-level anomaly (circular markers). (c) and (d) present, for the Pacific and Atlantic respectively, the associated principal components α2’s (solid blue lines). Also on (c), the Kuroshio southernmost latitude South of Tōkai is represented with the solid orange line (positive values indicate Kuroshio further to the south), the difference between sea level at Uragami and Kushimoto with the dot-dashed red line, and grey shadings represent periods of typical large meander (JMA, 2018). On (d), the dashed yellow line is the sea-level difference between the averages of northern and southern groupings of tide gauges, as in McCarthy et al. (2015). All timeseries on (c) and (d) are normalized. Colour shadings on (a) and (b) are, for each basin, the sea surface velocity magnitude composite difference based on the principal component α2 (period of α2 >+2/3 minus period of α2 <−2/3). The arbitrary threshold of ±2/3 was used, but taking any number between zero and one leads to akin patterns. The inset on (a) present the regression coefficient obtained when the principal component is regressed on the original tide gauges, with a zoom in on the Kii peninsula.
...read more