Elmar Friese

Four-Dimensional variational assimilation of atmospheric chemical data – application to regional modelling of air quality

The chemistry transport model system EURAD-IM and its variational data assimilation implementation are applied to air quality assessment problems The facility of joint initial value and emission rate optimisation together with a nested 4d-var module is employed to the measurement campaign BERLIOZ To emphasise the benefits of computationally efficient data assimilation for monitoring and simulating air quality, results of an operational 3d-var implementation are also given.

Long-Term atmospheric aerosol simulations — computational and theoretical challenges

Numerical simulations of aerosols in the atmospheric boundary can computationally be highly demanding since processes governing the formation and dynamics of atmospheric particles are extremely complex. It is necessary to apply reasonable simplifications to make the computations tractable. This paper gives an outline of the approach to the problem chosen for the EURAD model system. A special module MADOC (Modal Aerosol Dynamics with Organic compounds and Clouds) has been developed for aerosol simulations employing EURAD. Annual runs for a region in Central Europe are shown and discussed with regard to model content, performance and reliability.

Assessment of Source Receptor Relations by Inverse Modelling and Chemical Data Assimilation

Data assimilation and Inverse Modelling may serve various purposes by use of manifold techniques. A reasonable definition reads as follows: extracts the signal from noisy observations (filtering) interpolates in space and time (interpolation) and reconstructs state variables that are not sampled by the observation network (completeness).