The "Orsi fronts" are a commonly used climatological map of Southern Ocean frontal distributions, published on the Southern Ocean Atlas Database Page after Orsi et al. (1995).
See the package vignette/s for more details, and use citation("orsifronts")
for information on the sources.
Orsi, A. H., T. Whitworth III and W. D. Nowlin, Jr. (1995). On the meridional extent and fronts of the Antarctic Circumpolar Current, Deep-Sea Research I, 42, 641-673.