# Characterization of Wind Guests: A Study Based on Meteorological Tower Observations
## 3 Results and Discussion
### Vertical Profiles of Gust Descriptors  
Furthermore, in order to examine the dependence of various gust descriptors on observation height, the entire data were conditionally grouped according to the estimated Monin-Obukhov length for each 10-min period; subsequently the data within each group were analysed in a composite sense. Figure 6 depicts the vertical extent of the median value of the gust descriptors, which appeared to reveal a certain degree of dissimilarity. For example, it was found that the 10-min average wind speed and gust amplitude increased  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline  & **Mean Speed** & **Gust Amplitude** & **Gust Amplitude** & **Gust Factor** & **Peak Factor** & **TI** \\ \hline Weibull & \(-846.3\) & \(-1008.7\) & \(-612.2\) & \(128.8\) & \(-199.8\) & \(615.9\) \\ Gamma & \(-870.1\) & \(-1028.5\) & \(-617.6\) & \(202.4\) & \(-174.8\) & \(641.9\) \\ Log-Normal & \(-901.2\) & \(-1050.6\) & \(-637.2\) & \(206.7\) & \(-176.7\) & \(632.4\) \\ Log-Logistic & \(-875.2\) & \(-1037.9\) & \(-626.0\) & \(215.2\) & \(-174.4\) & \(659.5\) \\ \hline  & **Rise Time** & **Lapse Time** & **Rise Magnitude** & **Lapse Magnitude** & **GAF** & **Lg** \\ \hline Weibull & \(-1752.3\) & \(-1905.1\) & \(-733.3\) & \(-689.9\) & \(-767.8\) & \(-2930.8\) \\ Gamma & \(-1743.8\) & \(-1896.7\) & \(-730.3\) & \(-690.4\) & \(-761.7\) & \(-2927.8\) \\ Log-Normal & \(-1739.7\) & \(-1899.7\) & \(-744.8\) & \(-707.6\) & \(-742.7\) & \(-2940.6\) \\ Log-Logistic & \(-1752.4\) & \(-1905.6\) & \(-738.3\) & \(-697.7\) & \(-749.0\) & \(-2944.7\) \\ \hline \hline \end{tabular}
\end{table}
Table 4: Summary of log-likelihood (LogL) estimation.  
Figure 4: Scatter diagram: (**a**) gust factor vs. 10-min average wind speed; (**b**) gust factor vs. turbulence intensity. In (**b**), the empirical results from [PERSON] et al. (2015), [PERSON] (1984), [PERSON] et al. (2018) and [PERSON] (1978) are also depicted for comparison.  
Figure 5: Scatter diagram: (**a**) peak factor vs. 10-min average wind speed; (**b**) peak factor vs. turbulence intensity.  
monotonously with height. It should also be noted that the average wind speed and gust magnitude corresponding to very stable conditions tended to be somewhat smaller in magnitude than those in other atmospheric stability conditions, especially at lower levels.  
The vertical profiles associated with gust amplitude, rise magnitude and lapse magnitude are more or less consistent, where the magnitude under very stable conditions  
Figure 6: Vertical profiles of gust descriptors as a function of atmospheric stability condition. (**a**) 10-min average wind speed, (**b**) gust amplitude, (**c**) gust amplitude, (**d**) gust coefficient, (**e**) peak coefficient, (**f**) turbulent intensity, (**g**) rising time, (**h**) elapsed time, (**i**) rising amplitude, (**j**) elapsed amplitude, (**k**) gust asymmetry amplitude and (**l**) gust length scale.  
remains relatively constant or decreases modestly as the observation height increase. By contrast, the profiles under the remaining atmospheric stability conditions exhibited a moderate downward trend with increasing height. For gust factor and turbulence intensity, the magnitudes generally decrease in parallel with the increase in height; the deviation of profiles corresponding to different stability conditions was found to be minor. The peak factor also decreases with increasing height, and the rate of such a decrease is closely tied with stability condition. It was clearly shown that the peak factor under stable and neutral conditions decreased more slowly than those in other conditions. On the other hand, the definition of vertical structure of rising time, elapsed time and gust asymmetry factor was less clear. As for the gust length scale, the vertical profile was similar to those of mean wind speed and gust magnitude, which typically indicates a positive dependence on height. Moreover, under very stable and stable conditions, the amplitude of the gust length scale is smaller than that under other stable conditions.