Principal Investigator Paola Rizzoli
Among the various components of the Earth’s system, the ocean is arguably one of the least understood and least measured. Due to the paucity and sparsity of ocean measurements in space and time, it is very difficult to understand and quantify the multi-scale interacting ocean processes that range from small scale turbulence to world-wide ocean currents. That is why ocean models have become increasingly important to simulate these complex processes and understand their dynamics.
By and large, the ocean is driven by the atmosphere and the ocean circulation is a response to atmospheric forcing, i.e. wind stress, heat and moisture fluxes. In the tropical/ equatorial regions however the oceans are strongly coupled to the atmosphere and they exert the strongest feedback on atmospheric motions thanks to the intense sea surface exchanges. Thus in the tropical regions the interannual to decadal modes of climate variability are coupled ocean-atmosphere modes. The most famous example is the Pacific El Nino/Southern Oscillation ( ENSO ) mode. In the Atlantic ocean the most important coupled mode of variability is the interhemispheric dipole or meridional gradient mode, in which the Sea Surface Temperature (SST ) north-south gradient control the position of the InterTropical Convergence Zone (ITCZ) responsible for rainfalls or droughts over Brazil and West Africa. In the Indian ocean and Indonesian system the modes of variability are connected with the monsoon system which determines the dominant seasonal signal of the wind-driven circulation.
State-of-the-art, primitive equations numerical models have been used to simulate the Atlantic tropical circulation and, more recently, the Indonesian tropical circulation, comprising the western Pacific and eastern Indian oceans, the South China Sea (SCS) and the Indonesian Through Flow (ITF ) which is the major conduit of communication between the Pacific and Indian oceans. The model used is the Finite Volume Coastal Ocean Model (FVCOM) developed by Prof. Chen at UMass-Dartmouth and specifically designed for regions with extremely complex topography ranging from abyssal depths to coastal shelves.