Dissipation timescale of HI turbulence as a function of the galactocentric radius calculated with Eq. (4) for NGC 2403. The dashed black line is τ_d = 20 Myr obtained with a constant velocity dispersion of 10 km s⁻¹ and a constant scale height of 0.1 kpc (i.e. no flaring). The red curve and band are τ_d(R) and its uncertainty adopting the radially-decreasing σ_HI(R) and the increasing h_HI(R) from B19a.