A note on sodar return signals in the stable atmospheric boundary layer

A problem concerning the reliability of the determination of temperature Structure parameter C-T(2) with the help of sodar is considered. The results of comparisons between remote and ill situ measurements of C-T(2) in the atmospheric boundary layer (ABL) are briefly reviewed. Some examples of a systematic overestimation of the C-T(2) value derived from sodar return in the stable ABL are given. Possible technical and physical causes of the discrepancies are discussed, including: (1) the contribution of a partial (Fresnel) reflection of Sound from layers with a sharp temperature jump, (2) the anisotropy of small-scale turbulence, (3) the turbulence intermittency, (4) the contribution of quasi-wave air-density inhomogeneities, and (5) file contribution of wind speed fluctuations to backscattering. The cause (1) seems to be the main reason for the discrepancy.