| Modelling the turbulent transport in vegetation canopies as an important element of the main chemistry models is a key to properly simulate biosphere-atmosphere interactions. This research focuses on an improved understanding and model representation of turbulent exchange of reactive chemical compounds within and above the vegetation canopies. The main goal is to create an improved model that will be on one hand applicable for detailed local-scale (ecosystem) analysis of observations and on the other hand also in global scale models. The existing Single - Column Chemistry and Meteorological Model (SCM) now available in a stand-alone box version (MLC - CHEM) uses a rather simple representation for the turbulent closure as a function proportional to eddy diffusivity coefficient for heat - KH and the mean concentration gradient between the reference height of the surface and canopy layers (first closure approach). The two equations models (E-U, E-l, E-ε, E-ω) that simulate turbulent transport processes within and above canopy are becoming the best optimal approaches between the expected quality (practicality) of a model and its computational needs. On the other hand the similarity theory, recently extended, may account for a better representation of the atmospheric surface fluxes in the ABL with a very rough surface (forests). Linking the improved theory with the practicality of the -two equations models and taking into account the coupled atmosphere-canopy regimes, it can be expected to result in a better representation of canopy turbulent exchange processes. |
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