## 3 Results
### Evaluation of Basic Wind Speed and Wind Pressure Height Variation Coefficients
The basic principle is to compare the wind pressure values at different heights with the basic wind pressure values, while the air density value  
Figure 14: Comparison of basic wind speed values obtained by different calculation methods under different recurrence periods. \begin{table}
\begin{tabular}{c c c c c} \hline \hline \(\mathbf{G_{n}}\) & **10-RP (m/s)** & **30-RP (m/s)** & **50-RP (m/s)** & **100-RP (m/s)** \\ \hline G\({}_{0}\) & 11.99 & 13.56 & 14.29 & 15.28 \\ GEV & 10.94 & 11.94 & 12.38 & 12.94 \\ GEV\({}_{\text{n2}}\) & 14.10 & 15.25 & 15.75 & 16.39 \\ \hline \hline \end{tabular}  
* \(\mathbf{G_{0}}\)—model used in the standard; RP—basic wind speed for a specific return period.  
\end{table} 
Table 8: Basic wind speed values of different models under various return periods. is treated as a fixed value and canceled out in the fraction. The resulting empirical indices of 0.44 and 0.60 correspond to the wind profile indices for different terrain features (in the standards, the wind profile index for Class C terrain features is 0.22, and for Class D terrain features, it is 0.30, both raised to the power of 2\(\alpha\) in the general formula). Based on the optimal non-stationary GEV model and in conjunction with wind speed data from all 15 measured height layers, actual wind pressure values for each height layer can be obtained (assuming air density as a fixed value). Then, by calculating the basic wind pressure values from basic wind speed values, actual wind pressure height variation coefficients for the 15 height layers can be obtained. The wind pressure height variation coefficients in the standards provide values only for specific heights, but they can be converted to the heights used in the measured data in this paper using Equation (17). Since it is challenging to quantify ground roughness using measured data, actual values are computed using roughness indices identical to those specified in the standards for different terrain types, as shown in Table 9 (where the cutoff height for Class C terrain in the standards is 15 m and for Class D it is 30 m, meaning that wind pressure height variation coefficients below the cutoff height are taken at the position of the cutoff height, with an approximation for the 32 m height in Class D terrain to 30 m). The wind pressure height variation coefficients for different terrain types are shown in Figure 15. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Height (m)** & **Class C Terrain Features** & **Class D Terrain Features** \\ \hline
8 & 0.55 (0.65) & 0.32 (0.51) \\
15 & 0.55 (0.65) & 0.32 (0.51) \\
32 & 0.66 (0.91) & 0.32 (0.53) \\
47 & 0.89 (1.08) & 0.43 (0.66) \\
65 & 1.17 (1.24) & 0.56 (0.81) \\
80 & 1.50 (1.36) & 0.72 (0.91) \\
100 & 1.69 (1.50) & 0.81 (1.04) \\
120 & 1.92 (1.62) & 0.92 (1.16) \\
140 & 2.03 (1.74) & 0.98 (1.28) \\
160 & 2.09 (1.84) & 1.01 (1.38) \\
180 & 2.23 (1.94) & 1.07 (1.48) \\
200 & 2.37 (2.03) & 1.14 (1.58) \\
240 & 2.50 (2.20) & 1.20 (1.76) \\
280 & 2.53 (2.36) & 1.22 (1.94) \\
320 & 2.61 (2.50) & 1.25 (2.10) \\ \hline \hline \end{tabular} In parentheses are the values specified in the standards.  
\end{table} 
Table 9: Comparison of the wind pressure height variation coefficients between actual and standard values. Figure 15: Comparison of measured wind pressure height variation coefficients with specifications for different terrain types. The results indicate that, in Class C terrain features, the wind pressure height coefficients obtained from measurements and those specified in the standards are relatively close at lower heights. However, as the height increases, the wind pressure height variation coefficients obtained from measurements are significantly higher than those in Class C. For Class D terrain features, the wind pressure height variation coefficients specified in the standards are generally higher than those obtained from measurements. At lower heights, the difference between the two is relatively small, but as the height increases, the difference also increases.