A hierarchy of embedded model configurations (figure) of different grid resolution should make possible to carry out realistic, long term (several decades) simulations of the ocean and sea-ice circulation and variability at regional and global scale, and to perform sensitivity studies investigating key dynamical processes (requiring especially high resolution) and their impact at larger scales.

The primary concern of DRAKKAR is related to the circulation and the day-to-decade variability in the North Atlantic Ocean, as driven by the atmospheric forcing, by interactions between processes of different scales, by exchanges between basins and regional circulation features of the North Atlantic (including the Nordic Seas), and by the influence of the world ocean circulation (including the Arctic). New scientific objectives have emerged in the past two years relative to the variability of the Southern Ocean. DRAKKAR is also concerned by the role of the changing ocean circulation in ecosystem dynamics, and in climate through the transport of heat and freshwater and the uptake of atmospheric CO2.  

The scientific approach of the teams participating in DRAKKAR mainly relies upon numerical simulations. Therefore, the project has built a hierarchy of embedded model configurations, based on the NEMO code (http://www.lodyc.jussieu.fr/NEMO/), able to provide continued and systematic development and assessment of the ocean model components used in ecosystem, carbon cycle, and climate studies as well as in regional and operational oceanographic applications. The various DRAKKAR configurations will be run for multiple decades to provide a relevant, four-dimensional description of the atmospherically driven world ocean circulation and variability over the last 50 years. This description will allow (in the limits of model accuracy) to study the regional impacts of the global oceanic variability during this period, and to identify remote interactions between the North Atlantic and the World Ocean. It is also expected to contribute to the interpretation of the changes noticed in past and future ocean observations.