Study on actual behavior of mesoscale eddies in oceanic turbulence with satellite-image analysis and numerical simulation

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Ocean currents such as the Kuroshio and Oyashio, which strongly influence on the flow fields around Japan-Island-Chain, are characterized by the mesoscale eddies with the representative horizontal length scale of a few hundreds kilometers. Although the behaviors of the mesoscale eddies are closely related with the coastal environments, there are a number of unknown factors for the dynamical evolution of the mesoscale eddies. On the other hand, the head investigator in this project has been monitoring the large-scale patterns of the water temperature and velocity vectors on sea surfaces with the image processing for the polar orbiting meteorological satellite NOAA, and then attempted to examine ocean current structures and the actual motion of mesoscale eddies around Japan-Island-Chain. For further evolutions of the above study, in the present project, we investigate the actual behavior of mesoscale eddies in the flow fields around Japan-Island-Chain. Furthermore we try to develop the n … More umerical method of ocean current including the mesoscale eddies. The main results of the project are expressed in the followings.(1)Measurements for oceanic turbulence with the satellite-image analysisWe have conducted flow visualizations and sea-surface velocity measurements with NOAA/AVHRR thermal infrared data. Every day the monitoring of the oceanic turbulence has been continuously performed by capturing the satellite data. Combing the above satellite-based data and other published data concerning the oceanic turbulence, we have constructed the database for the oceanic turbulence around Japan-Island-Chain.(2)Ocean current simulations with a new nesting approachTo effectively incorporate the above measured ocean-current data on ocean current simulations, a new nesting procedure for ocean current model was developed and then applied to the ocean current simulation. Through the comparison of the computed and observed results, we have confirmed the fundamental validity of the present method. Less