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| Titel |
Rainfall erosivity in the Fukushima Prefecture: implications for radiocesium mobilization and migration |
| VerfasserIn |
J. Patrick Laceby, Caroline Chartin, Francesca Degan, Yuichi Onda, Olivier Evrard, Olivier Cerdan, Sophie Ayrault |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250106996
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| Publikation (Nr.) |
 EGU/EGU2015-6682.pdf |
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| Zusammenfassung |
| The Fukushima Dai-ichi nuclear power plant (FDNPP) accident in March 2011
led to the fallout of predominantly radiocesium (137Cs and 134Cs) on soils of the
Fukushima Prefecture. This radiocesium was primarily fixated to fine soil particles.
Subsequently, rainfall and snow melt run-off events result in significant quantities of
radiocesium being eroded and transported throughout the coastal catchments and
ultimately exported to the Pacific Ocean. Erosion models, such as the Universal Soil
Loss Equation (USLE), relate rainfall directly to soil erosion in that an increase
in rainfall one month will directly result in a proportional increase in sediment
generation. Understanding the rainfall regime of the region is therefore fundamental to
modelling and predicting long-term radiocesium export. Here, we analyze rainfall data
for ~40 stations within a 100 km radius of the FDNPP. First we present general
information on the rainfall regime in the region based on monthly and annual rainfall
totals. Second we present general information on rainfall erosivity, the R-factor
of the USLE equation and its relationship to the general rainfall data. Third we
examine rainfall trends over the last 100 years at several of the rainfall stations to
understand temporal trends and whether ~20 years of data is sufficient to calculate
the R-factor for USLE models. Fourth we present monthly R-factor maps for the
Fukushima coastal catchments impacted by the FDNPP accident. The variability of the
rainfall in the region, particularly during the typhoon season, is likely resulting in
a similar variability in the transfer and migration of radiocesium throughout the
coastal catchments of the Fukushima Prefecture. Characterizing the region’s rainfall
variability is fundamental to modelling sediment and the concomitant radiocesium
migration and transfer throughout these catchments and ultimately to the Pacific Ocean. |
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