AbstractFifty values of the rate of dissipation of turbulent kinetic energy, ε, deduced from spectra of vertical air velocity component made from an aircraft are presented. While generally in the range of values found by other authors the distribution of ε with height shows a good deal of scatter. This can in large measure be resolved by grouping the observations according to site roughness, season and wind speed, thus allowing for the varying contributions to ε of the wind‐shear and buoyancy‐force terms.The characteristic decay time of the turbulence (defined as the variance of vertical velocity divided by ε) increases consistently as the square root of height.