Suspended Particulate Matter Monitoring with GOCI Images After the Tohoku Tsunami (March 2011)

The Fukushima Daiichi nuclear disaster on 11 March 2011 was caused by the tsunami which was itself triggered by the devastating moment magnitude Mw9.0 earthquake. The present study investigates spatial and temporal changes of Suspended Particulate Matter (SPM) contents in the North-Eastern part of Japan, in the Pacific Ocean after the tsunami with a geostationary ocean color sensor. The Geostationary Ocean Color Imager (GOCI) launched in 2010, covers an area of 2,500 km x 2,500 km centered on the Korean peninsula, including the Japanese area and provides 8 images per day allowing the analysis of rapid changes that can occur during the day. Corrected from the atmospheric effect, the images were used to estimate the SPM concentrations maps. These maps were then analyzed between 5 March and 25 May 2011. The SPM notably increased (by 250%) both along the coast and in the Bay of Sendai shortly after the tsunami and stable structures of SPM appeared at 2, 14, 25 and 37 km from the coast. In this paper we attempt to explain the origin and the fate of the SPM concentration observed till the end of May 2011 through analysis of meteorological conditions, river discharges and tsunami waves properties.