Abstract
The distributions of upper ocean heat and fresh water (or salinity) have profound consequences on the atmosphere, including the weather and climate that influence many aspects of human societies. While their mean states are reasonably well described (or so we think), the difficulty of making high-accuracy measurements at high spatial and temporal resolution, uniformly distributed around the oceans, limits our knowledge of seasonal, and shorter, variations and constrains our ability to monitor changes over years and decades. This is more the case for salinity than for heat. The freshwater distribution influences the stability of the upper ocean, especially in polar regions. The increasing stability of the ocean at high latitudes associated with enhanced ice melt is believed to portend disruption to the global thermohaline circulation. Improvements in our ability to measure the heat and freshwater budgets and of the fluxes that control them, that will result from better remote sensing and in situ capabilities, will lead to a better understanding of the ocean, atmosphere, and climate system. This will be aided by the development of more realistic and more accurate numerical models capable of simulating the upper ocean and its interactions with the overlying atmosphere.