Establishment of numerical beach-litter hindcast/forecast models: An application to Goto Islands, Japan

► A system for hindcasting/forecasting the quantity of beach litter was established. ► An ocean circulation model, a two-way PTM, and inverse estimation were used. ► Twelve beach survey results, and satellite and forecast wind were also used. ► The computed quantities of beach litter were consistent with the observations. ► The accuracy of the model was reduced drastically by intense winds such as typhoons.