An Example of Application of Data Assimilation Technique and Adjoint Modelling to an Inverse Dispersion Problem Based on the ETEX Experiment
Inverse problems is one of comparably new and quickly developing areas. The problems themselves were known for ages but their exact solutions in many cases were either non-existing or requiring a forbidding amount of computations. It is a development of both mathematical methods (first of all, regularization techniques and statistical optimal filters) and new generations of computers that made some of the inverse problems approachable. In the field of atmospheric dispersion, an example of inverse problem is a so-called “compliance regime control” problem introduced by the Convention on Long-Range Transboundary Air Pollution (LRTAP). The task is to evaluate the true emission of primary acid pollutants in Europe from long-term observations and their comparison with model simulations. Host (1996) has shown that such a problem can be approached at a qualitative level only, which has been confirmed by another attempt of Sofiev & Sofieva (2000). In both papers, it is shown that without a heavy use of a-priory assumptions on emission values the uncertainties by far exceed the values themselves, while utilization of a-priory information destroys the signal from the observations together with the noise.
KeywordsEmission Flux Variational Data Assimilation Data Assimilation Technique Assimilation Cycle Adjoint Simulation
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