Figure 5

Two-dimensional histograms of $N_{\text{max}}^2$ and ζ _TP for every 6 h. (a) 0 h. (b) 6 h. (c) 12 h. (d) 18 h. (e) 24 h. (f) 30 h. (g) 36 h. (h) 42 h. (i) 48 h. Two-dimensional histograms of ζ _TP and $N_{\text{max}}^2$ for every 6 h for the tropopause below 14 km. Bin widths of ζ _TP and $N_{\text{max}}^2$ are 5×10⁻⁵ s ⁻¹ and 5×10⁻⁵ s ⁻², respectively. Numbers in each panel show the correlation coefficients r between ζ _TP and $N_{\text{max}}^2$. Black lines show the linear regression lines.