## 3 Results and Discussions
### Solar Radiation and Light Intensity  
As the conditions were sunny during the experiment, solar radiation had a direct effect on the CSGs. The maximum average solar radiation was 222.40 Wm\({}^{-2}\) from 12:00 h to 13:00 h. Figure 12 shows the total solar radiation for a day at the experimental site. In accordance with the optical properties of the plastic film, the CSG in Shenyang is oriented 5-6\({}^{\circ}\) from south to west, which maximizes the amount of sunlight entering the CSG through the south roof. At the same time, it is particularly difficult to measure the actual radiation absorbed by the north wall and the ground [49]. The south roof not only provides proper lighting conditions inside the greenhouse but also provides heat from solar radiation to the wall and ground. The heat accumulated throughout the day was released to maintain a stable environment inside the greenhouse and to fulfill the fundamental temperature needs for crop viability when solar radiation was not available at night. Furthermore, the capacity of the walls and ground to block solar radiation should be taken into consideration while building greenhouses.  
The average maximum light intensity outside the greenhouses was 54,612.5 lx (12:00 h to 13:00 h). The average maximum inside light intensity in the CSG without crops was 38,612.5 lx, 44,412.5 lx, and 48,612.5 lx (12:00 h to 13:00 h) in the bottom, middle, and top layers, respectively. The average maximum light intensity in the CSG with crops was 32,660.19 lx, 36,618.12 lx, and 40,660.48 lx (12:00 h to 13:00 h) in the bottom, middle, and top layers, respectively. Figure 13 displays the average outside light intensity and the light intensity at different layers inside two greenhouses, revealing a significant variation pattern throughout the day. Upon opening the curtain at 8:00 h, crop photosynthesis begins, leading to a linear increase in light intensity from 8:30 h to 11:30 h inside each greenhouse. Thereafter, the growth rate declined between 11:30 h and 12:30 h due to decreased CO\({}_{2}\) concentration. From 13:00 h to 15:00 h, there was a linear decrease in light intensity, and the cotton blanket was closed at 15:00 h. The average minimum light intensity was 0 lx (20:00 h to 4:00 h) both inside and outside of both greenhouses. It was observed that the CSG with crops had a higher light intensity at the bottom layer compared to the CSG without crops. Additionally, in the CSG with crops, the light intensity was more similar  
Figure 12: Outside solar radiation at the experimental site.  
between the bottom and middle layers, whereas the CSG without crops exhibited greater disparity between these layers. Thus, the presence of crops significantly impacted the light intensity distribution within the CSGs. The orientation of the greenhouse plays a crucial role in light distribution. Before midday, the eastern side experiences weaker light, while the western side receives stronger light, and this occurs vice versa in the afternoon [45].  
The weather was windy. At midday, the maximum average wind speed was 8.3 ms\({}^{-1}\) from the northeast (NE). The wind was from the southeast (SE) in the late afternoon. There was hardly any wind at night. Figure 14 shows the wind direction and speed during the experiment. The wind speed outside the greenhouse played a crucial role in maintaining optimal growing conditions, promoting plant health, and preventing the various issues associated with heat, humidity, diseases, and pollination.  
Figure 13: Different layers in the light intensity inside and outside the greenhouses: (**a**) with crops and (**b**) without crops.