# Characteristics of Aeolian Dune, Wind Regime and Sand Transport in Hobq Desert, China
## Results and Analysis
### Dominant Wind Characteristics  
In order to find out the dominant wind direction, we obtained the rose diagrams of the wind direction at Dongsheng, Baotou and Linhe stations during the years from 2009 to 2018 with daily wind data (Figure 7). The dominant wind direction of Dongsheng station was W from 2009 to 2016, and WNW from 2017 to 2018, but the frequency of W wind was less than 3% lower than that of WNW wind.Apart from the ENE wind in 2009, all the other years of Linhe station were SW wind, but after 2010 and 2014, it was mainly WSW. Different from Dongsheng and Linhe stations, the dominant wind direction of Baotou station varied greatly in the decade. To be specific, the prevailing wind was NW from 2009 to 2012, and ESE from 2013 to 2018.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Stations *} & \multicolumn{2}{c}{**Maximum Annual Wind Speed (m\(\cdot\)s\({}^{-1}\))**} & \multicolumn{2}{c}{**Average Annual Wind Speed (m\(\cdot\)s\({}^{-1}\))**} \\ \cline{2-5}  & **Z Value** & **Breakpoint** & **Z Value** & **Breakpoint** \\ \hline HJHQ & \(-1.073\) & — & 2.415 & 2017 \\ BT & \(1.073\) & — & 1.431 & — \\ LH & \(-1.431\) & — & \(-0.716\) & — \\ ETKQ & \(0.179\) & — & 1.968 & 2012 \\ DS & \(-2.236\) & 2013 & \(-3.220\) & 2013 \\ YJHL & \(0.537\) & — & 0.716 & — \\ \hline \hline \end{tabular}
\end{table}
Table 1: Trend and breakpoint detection of maximum and average annual wind speed from 2009 to 2018 (* referring to Figure 5 for the abbreviated names of stations).  
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multirow{2}{*}{**Stations *} & \multicolumn{2}{c}{**Maximum Annual Wind Speed (m\(\cdot\)s\({}^{-1}\))**} & \multicolumn{2}{c}{**Average Annual Wind Speed (m\(\cdot\)s\({}^{-1}\))**} \\ \cline{2-9}  & **Mean** & **SD.** & **Min.** & **Max.** & **Mean** & **SD.** & **Min.** & **Max.** \\ \hline HJHQ & 12.9 & 1.2 & 10.7 & 14.6 & 2.2 & 0.2 & 2.0 & 2.6 \\ BT & 11.9 & 4.1 & 6.7 & 16.7 & 2.3 & 0.9 & 1.2 & 3.1 \\ LH & 12.1 & 1.7 & 9.8 & 15.3 & 2.4 & 0.3 & 1.6 & 2.9 \\ ETKQ & 14.9 & 2.2 & 11.4 & 18.0 & 2.6 & 0.4 & 1.9 & 2.9 \\ DS & 10.4 & 1.4 & 8.8 & 13.0 & 2.5 & 0.2 & 2.3 & 2.9 \\ YJHL & 16.7 & 3.1 & 11.7 & 20.7 & 3.0 & 0.5 & 2.0 & 3.5 \\ \hline \hline \end{tabular}  
* SD, standard deviation. Min., the minimum value. Max., the maximum value.  
\end{table}
Table 2: Statistical summary of wind speed (* referring to Figure 5 for the abbreviated names of stations).  
According to the prevailing winds of Dongsheng, Baotou and Linhe stations in each year, the frequency of occurrence of different speed intervals was plotted (Figure 8). From the overall wind speed distribution, the average wind speed of the prevailing winds of each station from 2009 to 2018 was mainly distributed at 4-8 m/s. In contrast, the frequency percentage of Baotou station with wind speed greater than 6m/s was the lowest, the mean value was less than 30% and the maximum value wasonly 54%. As for the other two stations, they had little difference, the frequency percentage of the maximum wind speed greater than 6 m/s was about 85% and that of the mean value was about 45%. However, the frequency percentage of wind speed exceeding 10 m/s at each station was very low, with the maximum value of 10% or below.  
Figure 6: Distribution of the average (**a**) and maximum (**b**) annual wind speed (m\(\cdot\)s\({}^{-1}\)) in the Hobq Desert and adjacent areas.  
Figure 7: Variations of prevailing winds at Dongsheng, Baotou and Linhe stations from 2009 to 2018 in the Hobq Desert (referring to Figure 5 for the abbreviated names of stations).