Prediction of Short-Term Variations of the Warm-Core Rings in the Sea Off Sanriku

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The sea off Sanriku Coast is known as complicated oceanic conditions, which is formed by the Kuroshio and Oyashio currents and many warm-core rings. Because of this feature, it is sometime called as confluence zone. Since good commercial fish grounds are formed, this sea area is important for the Japanese fisheries. The purpose of present study was to develop a prototype system for forecasting of the short-term variations relating to the warm-core rings.First, we reprocessed the NOAA-A VHRR data locally received at the Tohoku University for generation of 4-6 sea surface temperature images in a day. Through investigation of these images, we picked up 92 events of the short-term variations. Foe all of these events, we conducted simulation experiments using the contour dynamics model, which shows good performance for each event. The warm-core rings propagate from the eastern ocean into the study area, and its number density becomes high. One of the factors which activate the short-term variations in the study area is the interaction of the warm-core rings with the high-number density.We analyzed the altimeter sea-surface height together with the high-resolution Sea Surface Temperature images, and developed methodology to estimate the sea surface height and surface velocity around the warm-core rings. Throughout this study, a basic system is established to predict the positions of SST fronts, which shows the locations of warm-core rings, using the satellite altimeter and SST measurements as the initial conditions.