The technique of tandem altimetric mapping (e.g., Le Traon et al., 1998) has been effectively applied to systematic tracking of oceanic eddies on global or regional scales, leading to the construction of several interdecadal eddy data sets with a grid size of 1/8°-1/4° on daily or weekly basis beginning from early 1990s (e.g., Chelton et al., 2011; Faghmous et al., 2015; Tian et al., 2019). Substantial progress has been made in many areas of marine science following the availability of these unprecedented measurements in conjunction with other concurrent multidisciplinary data sources (e.g.,