Similarity relationships for the convective boundary layer are used to derive surface heat flux and mixed layer depth from sodar measurements of the temperature structure parameter and the vertical velocity variance. Two different methods are presented and compared with direct measurements from the Oresund experiment which took place during the period 15 May-14 June 1984. The analyzed data were taken with two three-axis monostatic Doppler sodars manufactured by Sensitron, Sweden. Comparison with simultaneous direct measurements shows generally good agreement during convective conditions but also reveals some limitations of the methods.