FOOTPRINT PREDICTION OF SCALAR FLUXES USING A MARKOVIAN ANALYSIS

The contribution of upwind sources to measurements of vertical scalar flux density as a function of fetch ('footprint') is predicted using a Markovian simulation of fluid particle trajectories. Results suggest that both footprint peak position and magnitude change dramatically with surface roughness, thermal stability and observation levels. Results also indicate that the much used 100 to 1 fetch-to-height ratio grossly underestimates fetch requirements when observations are made above smooth surfaces, in stable conditions or at high observation levels. © 1990 Kluwer Academic Publishers.