Monitoring Suspended Particle Matter Using GOCI Satellite Data After the Tohoku (Japan) Tsunami in 201
Résumé
The Fukushima Daiichi nuclear disaster that occurred on March 11, 2011, was caused by the T¯ohoku tsunami, whichwasitselftriggeredbythedevastating9.0Mwmomentmagnitude earthquake. This study investigates spatial and temporal changes of the suspended particulate matter (SPM) content in the North-Eastern part of Japan (Pacific Ocean) using a geostationary ocean color sensor. The Geostationary Ocean Color Imager (GOCI), which is centered on the Korean peninsula but could also observe the Japanese area, is able to acquire eight images per day, thus allowing the analysis of rapid daily changes in water mass. TheanalysisofGOCIdatashowsthatSPMconcentrationnotably increasedbothalongthecoastandwithintheBayofSenda¨ıshortly after the tsunami. Motionless patterns of SPM were observed at 2, 14, 25, and 37 km from the coast. It is shown that SPM concentrationrapidlydecreasedonemonthlater.TheSPMconcentrationdid not remain high thefollowing year, contrary to what was observed for the Sumatra Tsunami in 2004. The origin of SPM is also investigated in this study. Our analysis suggests that some of the SPM originates from the resuspension of bottom sediments due to the reflectionofthetsunamionthecoastlinethatleadstothemigration of marine particles toward the sea surface. The fate of the SPM concentration is then discussed based on the analysis of meteorological conditions, river discharge, and tsunami wave properties
Domaines
Sciences de l'environnement
Origine : Fichiers produits par l'(les) auteur(s)
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