Abstract
The formative factors of a large scale of salinity stratification in Isahaya Bay are investigated by using a 3-D flow simulation model for the Ariake Sea. The stratification is formed by the supply of freshwater from the rivers flowing into the Ariake Sea. The Chikugo River and the Yabe River plays the most predominant role to the formation. The Chikugo River originated freshwater occupies about 52 % of the river originated freshwater flowing into Isahaya Bay and the freshwater from the Yabe River occupies about 29 %. The wind stress acting on the water surface gives a significant influence to the quantity of freshwater staying in Isahaya Bay. The continuous blowing of the northerly wind promotes the inflow in the Ariake Sea and increases the quantity of low salinity water in Isahaya Bay. On the other hand, the continuous blowing of the southerly wind generates the reverse phenomena.
