Mesoscale motion is often perceived to consist of a large number of phenomena, for example gravity waves, katabatic flows, convection and meandering to mention a few, and these have been studied in quite great detail. Unfortunately, it is not without difficulties to include these resulting detailed descriptions of these mesoscale phenomena into model parameterisations. On the contrary, one could suspect that one reason for operational models benefiting from being more diffusive than what can be justified from observations and large-eddy simulations is the presence of such unresolved and un-parameterised motion.
In this ongoing study I will attempt to quantify the collective effect of the mesoscales, rather than that of a particular phenomena. I will also discuss some of the fundamental problems involved with doing so. The software developed for the purpose is based on modern signal-processing methods and will be made publicly available upon completion of the project.