Estimation of the atmospheric surface momentum and heat fluxes using a high resolution acoustic radar

Abstract
The surface heat flux (Q_o) and the friction velocity (u_*) are important parameters of the Atmospheric Boundary Layer (ABL). Vertical velocity variance (σ_w)² profiles have been used to estimate the parameters Q_o and u_* from Acoustic Sounder (AS) data according to the similarity theory. A comparison was made using data from a 12 m high mast equipped with humidity, and fast responding wind and temperature sensors and a high resolution monostatic AS. The comparison confirms the ability of the (σ_w)² profile method to provide, even in a noisy environment (inhabitant area), estimates of these parameters with reasonable accuracy and on a continuous basis. The requirements for the method to be applied is that convective conditions or a minimum mechanical mixing exist and the level of acoustic noise is not too high.