|Fluxes of heat, water, gases and trace elements across the ocean-atmosphere interface are a key part of the global climate system. The oceans store and transport vast quantities of heat and play and play a critical role in the global carbon cycle. Holding 96% of the world's water, they dominate the hydrosphere. The oceans are intimately linked with natural climate variability at seasonal, inter-annual and longer timescales, as well as with anthropogenic climate change. Major observational programmes, such as were conducted in The World Ocean Circulation Experiment (WOCE) of the World Climate Research programme (WCRP), are designed to improve our understanding of the role of the ocean-atmosphere interface in the climate process, and to develop the ocean models necessary for predicting decadal climate variability and change.