Modelling surface radioactive spill dispersion in the Alborán Sea

2013

ISRN Oceanography

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Southern Iberian Peninsula coastal waters have a high ecologic and economic value. e objective of this work has consisted of describing numerical models which simulate the dispersion of particle-reactive tracers in these waters and reproducing measured concentration levels in water and bed sediment samples. Additionally, information on suspended matter concentration distributions and sedimentation rates is obtained. In the Alboran Sea, the model has been applied to simulate the transport of radionuclides introduced from atmospheric fallout. Transport pathways of heavy metals discharged from three rivers draining a large mining area have been obtained for the Gulf of Cadiz. It has been found that these rivers constitute a source of trace elements to the Mediterranean through the Strait of Gibraltar. Some characteristic times have been calculated, as well as �uxes of isotopes through the Strait of Gibraltar, as additional results of environmental interest.

Section: Resultsmentioning

confidence: 99%

Water Circulation, Sediment Transport, and Pollutant Dynamics in Southern Iberia Waters: A Review on Numerical Modelling Studies

2013

ISRN Oceanography

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“…A detailed comparison of results of the tidal model with measurements in the Alborán Sea is given in [3]. The calculated residual flows for the upper and lower layers, for the mean water exchanges through the Strait of Gibraltar, are presented in Fig.…”

Section: Resultsmentioning

confidence: 99%

Modelling radioactivity dispersion in the Alborán Sea, western Mediterranean

2009

Radioprotection

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Abstract.A numerical model which simulates the dispersion of non-conservative radionuclides in the Alboran Sea has been developed. Water currents are obtained from two hydrodynamic models working on the same domain: a 2D depth-averaged model is used two calculate tides and a 2-layer has been applied to obtain the residual (mean) circulation. The output of the hydrodynamic models is first applied to calculate suspended particle concentrations and sedimentation rates over the domain, which are also required by the radionuclide transport model. This assumes that radionuclides may be present in three phases: dissolved, suspended matter and bed sediments. Exchanges between the liquid and solid phases are described through kinetic transfer coefficients. The model has been applied to simulate the dispersion of 137-Cs and 239,240-Pu introduced in the sea from atmospheric fallout. Measured and computed radionuclide concentrations in the water column and in bed sediments are, in general, in good agreement.

“…Spatial resolution of the hydrodynamic models is 2 minutes in both longitude and latitude. Tides are calculated using a 2D-depth averaged model in each domain, which is a reasonable approach [1]. The two main constituents, M 2 and S 2 are included.…”

Section: Model Descriptionsmentioning

confidence: 99%

“…Tidal analysis is carried out and tidal constants are stored in files that will be read by the dispersion code. This method, standard in rapid-response models, allows a fast determination of tidal currents at any time and position [1]. The 2D depth-averaged hydrodynamic equations are standard and may be seen elsewhere [2].…”

Section: Model Descriptionsmentioning

confidence: 99%

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Models for radioactivity dispersion assessments in Andalusian coastal waters: Gulf of Cádiz and Alborán Sea

2009

Radioprotection

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Abstract. Rapid response models for the assessment of the consequences of a radioactive spill in the coastal waters of Andalusia (south of Spain) have been developed. These waters comprise the Gulf of Cadiz, GoC, (Atlantic Ocean) and the Alborán Sea, AS, (Mediterranean Sea) and two models are described, covering both sectors. This subject is of high relevance since these waters are the only connection between the Atlantic and the Mediterranean. Thus, there are intense shipping activities that for instance include the transit of nuclear submarines. The models include hydrodynamic sub-models appropriate to describe the water circulation in each area. Results from the hydrodynamic models have been carefully tested through comparisons with observed tides and currents. The dispersion models are based upon a particle-tracking technique. Thus, the radioactive spill is simulated by a number of discrete particles, each one equivalent to a number of units, whose paths are computed. Turbulent diffusion and radioactive decay are calculated using a stochastic Monte Carlo method. The radionuclide concentrations may be obtained at the desired time from the density of particles per water volume. Some applications and examples of results are given.