## 3 Results and Discussion
### Continuous Observation Experiment
#### 3.4.1 Characteristics of Atmospheric Wind Fields in Different Functional Areas  
In order to understand the atmospheric wind field conditions in the Hefei Economic Development Zone and the surrounding areas, a three-day navigation observation experiment was conducted from 3 August to 5 August 2021 to obtain the spatial and temporal distribution of the atmospheric wind field. The effectiveness of this vehicle-mounted Lidar in regional atmospheric wind field detection was verified. Figure 18 shows the wind plume maps obtained from the Lidar at the three sampling points. The direction of the wind profile arrow indicates the wind direction, and the arrow's color indicates the wind speed. Figure 18a illustrates a two-hour extensive navigation survey conducted at the RA site from 9 a.m. to 11 a.m. on 4 August. The average temperature of the environment was 29\({}^{\circ}\), the average humidity was 70%, the wind direction was towards the east, and the wind speed was at level 2. The wind speed and humidity near Shushan Lake were significantly higher than the other areas, with humidity levels as high as 78%. Moreover, the wind field navigation monitoring at the CD site is shown in Figure 18b. The missing area of wind profile in Figure 18 was caused by the shielding of buildings during laser cone scanning. Additionally, Figure 18c shows the navigation monitoring of the IP site. Due to the variability in the atmospheric environment at the IP site, we chose to monitor at several times on 5 August. During monitoring, the temperature was about 33 \({}^{\circ}\)C, the humidity was about 65-93%, the wind direction was easterly, and the wind speed was level 2.  
A wind-dominated pollutant transport process was observed during the IP site navigation monitoring, and Figure 19 reflects the variation in the wind field at different moments during the period. Figure 19a,b show the grey-scale plots of wind speed and wind direction as a function of time and height, respectively, obtained from CWML measurements on August 5 during the navigation monitoring, with the horizontal coordinates indicating time and the vertical coordinates indicating height. The shades of color in Figure 19a represent the wind speed magnitude, and the shades of color in Figure 19b indicate the wind direction, where 0\({}^{\circ}\) represents a northerly wind, 90\({}^{\circ}\) represents an easterly wind, 180\({}^{\circ}\) represents a southerly wind, and 270\({}^{\circ}\) represents a westerly wind. Accordingly, Figure 20 shows the wind speed and direction results measured at the local ground-based weather vertical coor  
Figure 18: Navigation monitoring results: (**a**) the RA site navigation monitoring; (**b**) the CD site navigation monitoring; (**c**) the IP site navigation monitoring.  
dinates indicating height. The wind plume represents the magnitude of horizontal wind speed, and the wind direction bar indicates the horizontal wind direction. The atmospheric wind field changes significantly with increasing height, and a more pronounced weather evolution can be seen more clearly in Figure 20. At the beginning of the experiment, the dominant wind direction was predominantly south-westerly, associated with the Hefei area being influenced by cold air moving south from the middle and high latitudes in summer. Later, possibly influenced by warm moist air from the tropical ocean moving northwards, the wind direction above 1 km shifted to southeasterly after 4 am, with significant wind shear. In this region, warm air meets cold air coming in from the south and forms a front at the junction. Evidently, the wind field changed dramatically at a low altitude of 1000 m, with local high wind values appearing at 4 a.m. and 6 a.m. After 3 p.m., the wind speed decreased significantly and remained basically less than 5 m/s.  
Figure 19: The IP site navigation monitoring wind profile: (**a**) wind speed; (**b**) wind direction.  
Figure 20: The results of wind speed and direction measured at the local ground-based weather station.