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| Titel |
3D model of radionuclide dispersion in coastal areas with multifraction cohesive and non-cohesive sediments |
| VerfasserIn |
Igor Brovchenko, Vladimir Maderich, Kyung Tae Jung |
| 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 |
250101823
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| Publikation (Nr.) |
 EGU/EGU2015-1060.pdf |
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| Zusammenfassung |
| We developed new radionuclide dispersion model that may be used in coastal areas, rivers
and estuaries with non-uniform distribution of suspended and bed sediments both cohesive
and non-cohesive types. Model describes radionuclides concentration in dissolved phase in
water column, particulated phase on suspended sediments on each sediment class types, bed
sediments and pore water. The transfer of activity between the water column and the pore
water in the upper layer of the bottom sediment is governed by diffusion processes. The phase
exchange between dissolved and particulate radionuclides is written in terms of desorption
rate a12 (s-1) and distribution coefficient Kd,iw and Kd,ib (m3/kg) for water
column and for bottom deposit, respectively. Following (Periáñez et al., 1996) the
dependence of distribution coefficients is inversely proportional to the sediment particle
size.
For simulation of 3D circulation, turbulent diffusion and wave fields a hydrostatic model
SELFE (Roland et. al. 2010) that solves Reynolds-stress averaged Navier-Stokes (RANS)
equations and Wave Action transport equation on the unstructured grids was used. Simulation
of suspended sediment concentration and bed sediments composition is based on (L. Pinto et.
al., 2012) approach that originally was developed for non-cohesive sediments. In present
study we modified this approach to include possibility of simulating mixture of cohesive and
non-cohesive sediments by implementing parameterizations for erosion and deposition fluxes
for cohesive sediments and by implementing flocculation model for determining settling
velocity of cohesive flocs.
Model of sediment transport was calibrated on measurements in the Yellow Sea which is
shallow tidal basin with strongly non-uniform distribution of suspended and bed
sediments. Model of radionuclide dispersion was verified on measurements of 137Cs
concentration in surface water and bed sediments after Fukushima Daiichi nuclear
accident.
References
Periáñez, R. Abril, J.M., Garcia-Leon, M. (1996). Modelling the dispersion of
non-conservative radionuclides in tidal waters—Part 1: conceptual and mathematical model.
Journal of Environmental Radioactivity 31 (2), 127–141
Roland, A., Y. J. Zhang, H. V. Wang, Y. Meng, Y.-C. Teng, V. Maderich, I. Brovchenko,
M. Dutour-Sikiric, and U. Zanke (2012), A fully coupled 3D wave-current interaction model
on unstructured grids, J. Geophys. Res., 117, C00J33
Pinto L., Fortunato A.B., Zhang Y., Oliveira A., Sancho F.E.P. (2012) Development and
validation of a three-dimensional morphodynamic modelling system for non-cohesive
sediments, Ocean Modell., (57–58), 1–14 |
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