Estimation of aerodynamic parameters under non-neutral stability conditions from Alpilles measurement data

Aerodynamic parameters (displacement height d and roughness length for momentum z₀), as well as friction velocity u. and temperature scaling parameter T., were estimated from the Alpilles energy balance measurement data. Air temperature and wind speed measurements at two heights and sensible heat flux data were needed in the estimation. Application of this method to two data sets measured in different ways for the temperature gradients found that the estimation of d and z₀ was applicable only when the temperature gradients were measured differentially. Sensitivity tests showed that the estimated d and z₀ were sensitive to the temperature gradients. However, both of the data sets produced good estimation of u. and T. The main advantage of this method is that it is applicable not only under near-neutral conditions but also under strong unstable conditions.