A method for the calculation of sensible heat flux from Sodar data in free convection conditions

This paper describes an useful algorithm to evaluate the surface value of the sensible heat flux by using Sodar data. The basic assumption for this method is the measurement of the three wind components, which can give an estimate of the atmospheric turbulence intensity. In particular, the vertical wind velocity variance s2 w is a function of the production of thermal and mechanic turbulence. When weather characterized by well developed free convection are considered, the contribution due to the mechanical turbulence (except in the surface layer, due to the friction effects) can be neglected, and during anticyclonic conditions almost all turbulent heat can be assumed as sensible heat. Therefore, the lower convective boundary layer is characterized by profiles of s3 w/z linearly decreasing with height, whose extrapolation to the ground can give an estimate of the surface sensible heat flux. The validation of this methodology was performed through an intercomparison of the energy involved in the warming of the convective boundary layer and through an intercomparison with the output of the standalone surface model LSPM (Land Surface Process Model).