## 3 Data Sources  
### Tropical Cyclones and Instruments  
In this study, the data of four typhoons (0601 typhoon Chanchu, 0606 typhoon Prapiroon, 0812 typhoon Nuri, and 0814 typhoon Hagupit) and three hurricanes (0504 hurricane Katrina, 0510 hurricane Rita, and 0512 hurricane Wilma) were comparatively analyzed. The detailed descriptions of the observation site exposures and the observation tower configurations for the four typhoons and three hurricanes were presented in [PERSON] et al. (2016) and [PERSON] et al. (2012), respectively. The GPS coordinates of the observation stations were listed in Table 1. As the latitudes of all observation stations are around 25\({}^{\circ}\), the latitude of the standard condition is set to be 25\({}^{\circ}\) for the convenient of calculation.  
It is noted that the distance constant \(\lambda\) of the propeller anemometer is an important factor to calculate the peak factor and gust factor as this type of anemometer mechanically filters the amplitudes  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Tropical Cyclones** & **Tower** & **Latitude** & **Longitude** \\ \hline \multirow{2}{*}{Chanchu} & RBT & 22.7337\({}^{\circ}\) & 115.5734\({}^{\circ}\) \\  & OT & 23.5510\({}^{\circ}\) & 117.0020\({}^{\circ}\) \\ \hline \multirow{2}{*}{Prapiroon} & BT & 21.4519\({}^{\circ}\) & 111.3149\({}^{\circ}\) \\ \hline \multirow{2}{*}{Nuri} & MFB & 22.1810\({}^{\circ}\) & 113.5630\({}^{\circ}\) \\  & DIT & 22.1413\({}^{\circ}\) & 113.7096\({}^{\circ}\) \\ \hline \multirow{2}{*}{Hagupit} & ZT & 21.4509\({}^{\circ}\) & 111.3745\({}^{\circ}\) \\  & ST & 21.2538\({}^{\circ}\) & 110.6541\({}^{\circ}\) \\ \hline \multirow{4}{*}{Katrina} & T1 & 29.8253\({}^{\circ}\) & \(-\)90.0319\({}^{\circ}\) \\  & T2 & 29.4441\({}^{\circ}\) & \(-\)90.2628\({}^{\circ}\) \\  & T3 & 30.4720\({}^{\circ}\) & \(-\)88.5308\({}^{\circ}\) \\ \hline \multirow{4}{*}{Rita} & T0 & 29.9512\({}^{\circ}\) & \(-\)94.0220\({}^{\circ}\) \\  & T3 & 29.9548\({}^{\circ}\) & \(-\)93.9542\({}^{\circ}\) \\  & T5 & 30.0797\({}^{\circ}\) & \(-\)93.7841\({}^{\circ}\) \\ \hline \multirow{4}{*}{Wilma} & T0 & 25.9008\({}^{\circ}\) & \(-\)81.3114\({}^{\circ}\) \\  & T1 & 26.1458\({}^{\circ}\) & \(-\)80.5067\({}^{\circ}\) \\ \cline{1-1}  & T2 & 25.8681\({}^{\circ}\) & \(-\)80.8997\({}^{\circ}\) \\ \cline{1-1}  & T3 & 25.7516\({}^{\circ}\) & \(-\)80.3780\({}^{\circ}\) \\ \hline \hline \end{tabular}
\end{table}
Table 1: The GPS coordinates of observation towers. Reproduced with permission from ([PERSON] et al., 2019), Elsevier, 2019.  
of gusts with wavelengths less than \(2\pi\lambda\) due to the mechanical limitations [10]. In this study, the propeller anemometers of models R.M. Young 05103L and R.M. Young 27106R were respectively used to measure typhoons and hurricanes. The specifications of these two propeller anemometers are listed in Table 2. Based on the parameters in Table 2, the data measured by propeller anemometers were corrected according to Equation (24). In addition to propeller anemometers, the sonic anemometers were also utilized in the field measurement of typhoons. Specifically, two 3-D ultrasonic anemometers (WindMaster(tm) Pro., Gill Instruments Ltd., Lymington, UK) were installed on tower RBT and one 3-D ultrasonic anemometer (HD2003, Delta Ohm Srl, Selvazzano Dentro, Italy) were setup on tower OT for the measurements of Typhoon Chanchu; one HD2003 anemometer were installed on tower BT to acquire data from Typhoon Prapiroon, and towers DIT and ST were equipped with Gill WindMaster(tm) Pro. anemometers. The specifications of the utilized sonic anemometers are also listed in Table 2. For the data obtained from sonic anemometers, the filter function presented by Equation (23) were used for the correction.