OSMOSIS: Ocean Surface Mixing, Ocean Sub-mesoscale Interaction Study

The atmosphere and oceans control the Earth's climate. The ocean surface boundary layer (OSBL) is the upper 300m or so of the oceans and it is the part of the ocean that is directly affected by the atmosphere. So the OSBL acts to couple the atmosphere and deeper oceans together: it mediates the transfer of heat, momentum and important greenhouse gases such as carbon dioxide, and controls the supply of nutrients to the plankton that grow in the ocean surface boundary layer. In addition the temperature of the sea surface has an impact on weather forecasts for timescales of days to seasons. The sea surface temperature is largely set by the OSBL. It is clear then that the ocean surface boundary layer it truly at the heart of weather and climate. But our knowledge of the OSBL is very incomplete, and this means our quantitative models are not accurate. Nevertheless, it is a very exciting time to be doing research into the OSBL because we have new ideas about the fundamental processes that control the its evolution from timescales of days to years, and we also have exciting new tools to measure the ocean surface boundary layer. OSMOSIS will bring together a team of meteorologists and oceanographers with backgrounds in theory, computer modelling and observations, with the aim of making a step change to our understanding and our predictive power of the OSBL. We shall do this with a combination of new theory and new measurements. We will develop theory into the fundamental physics of the OSBL using the powerful new computational tools, which allow us to simulation the three-dimensional, time varying motions of the water in the OSBL. By careful analysis of the results of these computations we shall develop simpler representations of the OSBL that can be used in weather and forecast models. Will plan two research cruises and a range of instruments attached to fixed moorings to measure the OSBL at a level of detail never previously attempted. The cruises will enable us to observe at close quarters how the OSBL evolves under different weather regimes. The moorings will be left to gather data over a whole year, which will show us the seasonal evolution of the OSBL. These data will provide stringent tests for our new theoretical ideas, and our simpler representations. Finally, we are doing this research in conjunction with the Met Office and the European Centre for Medium Range Weather forecasting. We shall work closely with them doing the project, and their involvement will ensure that our results make a difference to the practise of weather and climate forecasting.