## 3 Results
### Result of Typhoon Rammasun from an S-band Radar of CINRAD  
In the Philippines, Typhoon Rammasun was also known as tropical cyclone Glenda. Typhoon Rammasun was recorded as one of the only two category five super typhoons in the South China Sea. Typhoon Rammasun made its landfall close to Wenchang City of Hainan province on 17 July 2014. Numerous houses were damaged due to Typhoon Rammasun and almost 750,000 individuals were evacuated. Haikou radar observations of the twice-aliased situation exist, with the maximum maintained real wind speed of 92 m/s, which presented the dealiasing algorithm with a greater challenge. There was another challenge of tropical cyclone dealiasing when the storm eye was near to the radar center since the radar radial velocity observations showed asymmetry at the two sides of the zero velocity line. The Haikou S-band radar station located near the north coast of Hainan has a Nyquist velocity of 35.34 m/s and was near to the storm eye of typhoon Rammasun at 06:35 (UTC), on 18 July 2014, when Rammasun almost made its landfall. Therefore, this supplied the best observation data to examine ADDA's performance in exceeding situations. Figure 2a,c, demonstrates the original radial velocity fields collected from Haikou radar station at a 2.4\({}^{\circ}\), 6.0\({}^{\circ}\), and 14.6\({}^{\circ}\)elevation, respectively. As can be seen in Figure 2, the eye of Rammasun was about 75 km away from the east of the radar center at that moment. Many radial velocity gates in the south and north of the typhoon eye were obviously twice-aliased. ADDA properly selected the first reference radial close to the zero-line and correctly dealiased these twice-aliased gates. Figure 3b shows the ultimate dealiasing result at elevation \begin{table}
\begin{tabular}{c c c c c} \hline
**Weather** **Condition** & **Radar Site** & **Volumes** & **Titles** & **Period** \\  & & **Number** & **Number** & **Number** & **Period** \\ \hline Typhoon & Haikou (CR, S) & 144 & 1296 & 21:00 UTC 17–11:00 UTC 18 July 2014 \\ \hline Typhoon & Hualian (TW, S) & 89 & 712 & 10:00–22:00 UTC 18 September 2011 \\ \hline Hurricane & KLIX (NR, S) & 156 & 1376 & 11:00–23:00 UTC 28 August 2012 \\ \hline Hurricane & KAKQ (NR, S) & 147 & 1320 & 14:00 UTC 27–02:00 UTC 28 August 2011 \\ \hline Squall line & Guangxi (CR, S) & 109 & 981 & 10:18–21:17 UTC 30 March 2014 \\ \hline Squall line & Zhangbei (CR, C) & 119 & 1071 & 03:05–14:59 UTC 23 July 2009 \\ \hline Hailstorm & Datong (CR, C) & 85 & 707 & 04:07–12:06 UTC 27 June 2008 \\ \hline \end{tabular}
\end{table} 
Table 1: Summary of the seven study cases. (CR: China radar network (CINRAD), TW: TaiWai, NR: NEXRAD (Next Generation Weather Radar); S: S-band, C: C-band). angle of 2.4\({}^{\circ}\) after running all these five dealiasing modules. In Figure 2c, almost 30% of the valid radial velocity gates were aliased and a discontinuous aliased echo existed in the northeast of the eye of typhoon Rammasun at the elevation angle of 4.3\({}^{\circ}\). The local dealiasing scheme with the least-square error check elaborated in module 5 of ADDA played a very important role for the 4.3\({}^{\circ}\) elevation angle. As demonstrated in Figure 2d, the ADDA scheme smoothly dealiased these severely aliased radial velocity gates. In the 9.9\({}^{\circ}\) elevation angle, the G-VAD scheme mentioned in module 2 was certified as beneficial for properly choosing the first reference radial around 92\({}^{\circ}\), as presented in Figure 3e. The proper first reference radial guaranteed that the following modules were implemented successfully, resulting in the satisfactory dealiasing of the 9.9\({}^{\circ}\) elevation angle, as demonstrated in Figure 3f. Figure 2: Radial velocity fields observed by Haikou radar station in the China radar network (CINRAD) system at 06:35 (UTC), 18 July 2014.