Inverse modelling for mercury over Europe Y. Roustan and M. Bocquet Centre d'Enseignement et de Recherche en Environnement Atmosphérique, Joint laboratory École Nationale des Ponts et Chaussées/EDF R&D, avenue Blaise Pascal, 77 455 Champs sur Marne, France
Abstract. The fate and transport of mercury over Europe is studied using a regional Eulerian
transport model. Because gaseous elemental mercury is a long-lived species in the atmosphere,
boundary conditions must be properly taken into account. Ground measurements of gaseous mercury are very sensitive
to the uncertainties attached to those forcing conditions.
Inverse modelling can help to constrain the forcing fields and help
to improve the predicted mercury concentrations.
More generally, it allows to reduce the weaknesses of a regional model against
a global or hemispherical model for such diffuse trace constituent.
Adjoint techniques are employed to relate rigorously and explicitly the
measurements to the forcing fields. This way, the inverse problem is clearly
defined. Using EMEP measurements of gaseous mercury and performing the
inversions, it is shown that boundary conditions can be improved
significantly as well as the forecast concentrations. Using inverse modelling
to improve the emission inventory is however much more difficult. Indeed, there
are currently not enough mercury monitoring stations, and they are located
far away from the center of Europe.
Citation: Roustan, Y. and Bocquet, M.: Inverse modelling for mercury over Europe, Atmos. Chem. Phys., 6, 3085-3098, doi:10.5194/acp-6-3085-2006, 2006.