Top row: vertical diffusion coefficient K_zz(r) = H_p·v_z(r) [cm² s^-1] applying the smoothed vertical velocities of the radiative-hydrodynamic HD 189733b model at latitudes θ = 0° and θ = 45°, as a function of pressure at Δφ = + 45° longitude intervals. The K_zz(r) = 10⁷p^-0.65 (p [bar]) expression from Parmentier et al. (2013) is shown as dash-dotted lines. Middle row: the vertical mixing timescales τ_mix,diff [s] derived from the HD 189733b radiative-hydrodynamic model results at latitudes θ = 0°, θ = 45°, as a function of pressure at Δφ = + 45° longitude intervals. Bottom row: ratio of the mixing and advective timescales at θ = 0°, 45° respectively. The ratio of the timescales stays approximately equal at all pressures. Solid, dotted and dashed lines indicate dayside, day-night terminator and nightside profiles respectively.