Surface wind variation over local terrain undulations

Inverse dispersion methods are commonly applied to infer gas fluxes to the atmosphere arising from point and area sources. Typically the needed dispersion model will assume the velocity statistics of the atmospheric surface layer to be undisturbed (i.e. horizontally homogeneous) so that Monin-Obukhov (MO) similarity applies, however at many sites that assumption is compromised by terrain undulations. In that context, mean wind speed variability has been measured with twelve cup anemometers at a single height (1.1 m AGL) over an undulating field, during a tracer experiment intended to indicate the performance of the "backward Lagrangian stochastic" (MO-bLS) method for inverse dispersion (bLS was subsequently applied at the site to measure the methane flux from cattle confined in a long, narrow pen). The measured wind field will be compared with a linearized model of winds over gentle terrain.