Japan Geoscience Union Meeting 2015

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International Session (Oral)

Symbol A (Atmospheric and Hydrospheric Sciences) » A-CG Complex & General

[A-CG07] Continental-Oceanic Mutual Interaction: Global-scale Material Circulation through River Runoff

Wed. May 27, 2015 11:00 AM - 12:45 PM 201B (2F)

Convener:*Yosuke Yamashiki(Global Water Resources Assessment Laboratory - Yamashiki Laboratory Graduate School of Advanced Integrated Studies in Human Survivability Kyoto University), Yukio Masumoto(Japan Agency for Marine-Earth Science and Technology), Swadhin Behera(Climate Variation Predictability and Applicability Research Program Research Institute for Global Change/JAMSTEC, 3173-25 Showa-machi, Yokohama 236-0001), Yasumasa Miyazawa(Japan Agency for Marine-Earth Science and Technology), Toshio Yamagata(Japan Agency for Marine-Earth Science and Technology), Kaoru Takara(Disaster Prevention Research Institute, Kyoto University), Chair:Yosuke Yamashiki(Global Water Resources Assessment Laboratory - Yamashiki Laboratory), Yasumasa Miyazawa(Japan Agency for Marine-Earth Science and Technology), Kaoru Takara(Disaster Prevention Research Institute, Kyoto University)

11:45 AM - 12:00 PM

[ACG07-09] CHARACTERISATION OF RADIOCESIUM IN SEDIMENT OF THE SENDAI BAY OFF THE ABUKUMA RIVER DELTA

*Yosuke YAMASHIKI1, Mochamad Adhiraga Pratama2, Hideo YAMAZAKI3, Masanobu ISHIDA3, Yoshihiro NIWA4 (1.GSAIS Kyoto University, 2.GSE Kyoto University, 3.Kinki University, 4.GSS The University of Tokyo)

Keywords:Abukuma River, Radiocaesium, Bottom Sediment

Seasonal variation of radiocaesium concentration in the bottom sediment near Abukuma River mouth were observed in order to verify the potential impact of high radiocaesium flux from Abukuma River into the Pacific Ocean. Based on the hydrodynamic parameter obtained in the bay, complex estuary circulation were affecting contaminated suspended material along the shoreline, indicating that contaminated bottom sediment are always in the motion both affected by the river flow and estuary circulation. According to the numerical estimation of radiocaesium flux from Abukuma river basin, it was indicated that the highest concentration of bottom sediment may occur just after the heavy rainy season, whereas during dry season concentration of the bottom sediment might be reduced. Our seasonal observation showed that highest concentrations were observed in September, when the precipitation and thus total road from Abukuma river basin was highest in 2013, where observation in the dry season showed lower concentration of radiocaesium. It was first observed proof which, bottom sediment contamination is affected directly by the seasonal changes of radiocaesium flux of inflowing river basin affected direct fallout from FDNPP.