Fig. 2: Variance frequency spectra of the principal components in without tides ensemble.

a Variance frequency spectra of the principle component for EOF1, which is corresponding to scales 81 km in spatial scale. b For EOF30, which is corresping to scale 66 km in spatial scales. c For EOF2000, which is corresponding to scale 20 km in spatial scale. The principle components are derived from the EOF results of the depth average velocity anomalies. The black solid lines show the spectra, and the green lines represent the slope of the spectra.