Comparison of the rms velocities and temperature fluctuations in the constant-Re case with two models approximating their global behaviour. Solid lines show u_rms (top), w_rms (middle), and ϑ_rms (bottom). Dashed lines show the model, in which u_e(z) ∝ e^{− β_uz/H}, w_e(z) ∝ e^{− β_wz/H}, and ϑ_e(z) ∝ e^{− β_ϑz/H} with , , and β_ϑ = 1.7. Dotted lines show the improved model given by Eqs. (52)−(54) with γ = 1.3. The coefficients of proportionality have been adjusted for each variable independently.