Satellite-based Monitoring of Behavior of Fine Sediment Discharged from Rivers

Abstract

This paper evaluates the fine sediment discharge patterns of rivers in the northern part of Vietnam and the Enshu-nada coast in Japan. The monitoring system was developed based on the MODIS satellite data which has archives for the last 16 years. The system enabled us to capture the different patterns of fine sediment discharge with its relative magnitudes and we found through the monitoring that the amount of turbid discharge in the rivers of the Red River system was reduced while that of the Ma River system tended to be increased. The results of the satellite-based monitoring system present the discharge pattern on a daily, monthly and yearly basis. The daily basis results support the feasibility of the use of the present MODIS-based monitoring system for the investigation of turbidity patterns which may be affected by daily factors such as tides and winds. Monthly or yearly averaged turbidity patterns along the coasts provide us with the additional information of the long-term trends of sediment discharge and the behavior of littoral movement. The results of suspended sediment patterns and their magnitudes are further discussed from a previous study around the Ma river study site. For instance, the decreasing trend of the Red River discharge and increasing trend of the Ma river discharge surely corresponded to the estimated littoral drift based on the analysis of thermoluminescence.