Intercomparison study of atmospheric mercury models: 2. Modelling results vs. long-term observations and comparison of country deposition budgets


Alexey Ryaboshapko, O. Russell Bullock Jr., Jesper Christensen, Mark Cohen, Ashu Dastoor, Ilia Ilyin, Gerhard Petersen, Dimiter Syrakov, Oleg Travnikov, Richard S. Artz, Didier Davignon, Roland R. Draxler, John Munthe, Jozef Pacyna


Science of the Total Environment, 2007, doi:10.1016/j.scitotenv.2007.01.071


Abstract - Five regional scale models with a horizontal domain covering the European continent and its surrounding seas, two hemispheric and one global scale model participated in the atmospheric Hg modelling intercomparison study. The models were compared between each other and with available measurements from 11 monitoring stations of the EMEP measurement network. Because only a very limited number of long-term measurement records of Hg were available, significant attention was given to the intercomparison of modelling results. Monthly and annually averaged values of Hg concentrations and depositions as well as items of the Hg deposition budgets for individual European countries were compared. The models demonstrated good agreement (within 20%) between annual modelled and observed values of gaseous elemental Hg. Modelled values of Hg wet deposition inWestern and Central Europe agreed with the observations within 45%. The probability to predict wet depositions within a factor of 2 with regard to measurements was 50-70% for all the models. The scattering of modelling results for dry depositions of Hg was more significant (up to 50% at the annual scale and even higher for monthly data). Contribution of dry deposition to the total Hg deposition was estimated at 20-30% with elevated dry deposition fluxes during summer time. The participating models agree in their predictions of transboundary pollution for individual countries within 60% at the monthly scale and within 30% at the annual scale. For the cases investigated, all the models predict that the major part of national anthropogenic Hg emissions is transported outside the country territory.



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