An example of long-term variability along 55W, perhaps interannual, for current and temperature distributions during mid-1975-1977 is presented. The existence of significant energy in the 55W data set at time scales longer than mesoscale (50-150 days) has been clear for , some time, but this is a first description of the latitudinal and vertical configuration of this low-frequency variability....
Schmitz, William J., and Michael S. McCartney. 1982. "An example of long-term variability for subsurface current and hydrographic patterns in the western North Atlantic." Journal of Marine Research 40, (S). https://elischolar.library.yale.edu/journal_of_marine_research/1663