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タグ「long-range transport」

Simulation of the chernobyl radioactive cloud over Europe using the eurad model

ecology・environment

Title: Simulation of the chernobyl radioactive cloud over Europe using the eurad model

Author: H. Hass, M. Memmesheimer, H. Geiβ, H.J. Jakobs, M. Laube, A. Ebel

Reference: Atmospheric Environment. Part A. General Topics, Volume 24, Issue 3, 1990, Pages 673-692

DOI: http://dx.doi.org/10.1016/0960-1686(90)90022-F

Keywords: Forecast; accidental release; Chernobyl; long-range transport; deposition; radionuclides

Abstract: The opean cid eposition Model (EURAD) is used to investigate the long-range transport (LRT) and deposition of radioactive material in Europe during the first week after the Chernobyl accident. Emphasis is laid on using the model system in a forecast mode as possibly would be done shortly after such an event. Thus, meteorological fields are predicted with the PSU/NCAR mososcale model MM4.The multilayer Eulerian model CTM ( hemistry ransport ) is applied to compute transport and deposition of Cs-137 and I-131 using the predicted meteorological fields. However, the accident scenario was estimated using published data. The model results and performance are discussed by comparison with observations. It is demonstrated that the model can reproduce certain observed characteristics of the radioactive cloud, i.e. trends in surface air concentrations, arrival times and wet deposition patterns. This leads to the suggestion that the predictive capability of the EURAD-system has a relatively high level considering the fact that several simple approaches were used.

URL: http://www.sciencedirect.com/science/article/pii/096016869090022F

Transport of radioactive particles from the Chernobyl accident

ecology・environment

Title: Transport of radioactive particles from the chernobyl accident

Author: Roy Pöllänen, Ilkka Valkama, Harri Toivonen

Reference: Atmospheric Environment, Volume 31, Issue 21, November 1997, Pages 3575-3590

DOI: http://dx.doi.org/10.1016/S1352-2310(97)00156-8

Keywords: Chernobyl accident; radioactive particles; long-range transport; particle transport

Abstract: After the Chernobyl accident large and highly radioactive particles were found in several European countries. Particles > 20 μm in aerodynamic diameter were transported hundreds of kilometres from the plant, and they were sufficiently active (> 100 kBq) to cause acute health hazards. Here, a particle trajectory model is used to identify the areas of large particle fallout. Effective release height of the particles and atmospheric phenomena related to their transport are investigated by comparing particle findings with locations given by trajectory calculations. The calculations showed that in the Chernobyl accident either the maximum effective release height must have been considerably higher than previously reported (> 2000 m) or convective warm air currents may have lifted radioactive material upwards during transport. Large particles have been transported to other areas than small particles and gaseous species. The particulate nature of the release plume must be taken into account in dispersion and transport analyses. Air parcel trajectories alone are not necessarily sufficient for identifying the fallout area of radioactive material.

URL: http://www.sciencedirect.com/science/article/pii/S1352231097001568

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