Observational evidence of interannual to decadal-scale variability of the subsurface temperature-salinity structure of the world ocean

We present a brief summary of some results describing interannual to decade scale variability of ocean parameters, focusing on subsurface temperature and salinity. We focus attention on the North Atlantic, where it is very clear that a major redistribution of heat and salt has been occurring since 1960, from the sea surface to at least 3000 m depth. We then discuss implications of these examples of historical variability toward development of an ocean monitoring system for the ocean interior. The purpose of this paper reflects our belief that the justification of, and planning for, any such monitoring system for the world ocean, should be based on analyses of historical oceanographic data. These analyses should document the time and space scales associated with variability of the world ocean.