Author(s): Sha Lou; Akihide Tada; Akira Tai; Shinichiro Yano; Seiji Suzuki; Shuguang Liu
Linked Author(s): Shinichiro Yano, Akira Tai
Keywords: POM; Kinematic Wave Method; Salinity; Temperature; The Yatsushiro Se
Abstract: Because of methylmercury pollution in 1950s which caused the well-known Minamata Disease, many measurements have been implemented in Minamata Bay, located in southeast coastal area of the Yatsushiro Sea, Japan. Although at present further research still needs conducting to comprehensively understand the dynamic behavior of mercury in Minamata Bay, some research has demonstrated relationship between mercury concentration and seawater characteristics. On basis of the cruises in the Yatsushiro Sea from 1976 to 2009 by Kumanoto Prefecture, salinity and temperature fields in the Yatsushiro Sea are analyzed by Princeton Ocean Model (POM). To reproduce the actual situation, recorded discharge of A-Class river (the Kuma River) and estimated discharge of two B-Class rivers (the Komenotsu River and the Minamata River) by a watershed model using Kinematic Wave Method (KWM) are adopted. Rainfall rate (mm/h) and heat fluxes utilizing data from the nearby land meteorological stations are also took into account. Results show that mostly simulated salinity and temperature agree with measured data well. Simulated salinities are higher than the measured ones around the Kuma River's mouth and in southern part of the Yatsushiro Sea. Deviations reduce with the increasing of water depth. Effect of A-Class river is much larger than that of B-Class rivers which only have little influence in coastal area. Accurate rain rate needs using to enhance precision in the open sea area. Temperature in surface layer is about 2-3°C higher than that in deeper water column in most cases. In summer season heat fluxes could affect not only surface layer but also middle and even bottom layer. River's inflow has some influence around river mouth area. Temperatures around the Kuma River's mouth is marginally higher than that in the adjacent waters in simulation.
Year: 2013