Assessment of Doppler Wind Lidar Detection Efficiency and Influencing Factors at Plateau Airport: A Case Study of Lhasa Gonggar Airport

Doppler wind lidar (DWL) demonstrates significant advantages in wind field detection under clear weather conditions and has been widely applied in airports with complex wind environments. However, its detection performance is highly susceptible to weather conditions and meteorological factors. To address this issue, this study analyzes the detection efficiency of DWL based on data collected at Lhasa Gonggar Airport from August 2023 to April 2024, along with ground-based meteorological observations. The results indicate that when the detection efficiency dropped to 40%, the average detection range for the plan position indicator (PPI) mode and Doppler beam swinging (DBS) mode were 5.3 km and 2.7 km, respectively. The influence of different underlying surface types on detection efficiency was minimal, with detection efficiency at a 270 degrees azimuth slightly better than at a 90 degrees azimuth. A 4 degrees elevation angle performed better than a 6 degrees elevation angle. During the study period, the detection efficiency generally improved, with the lowest detection efficiency being observed in August, suggesting that precipitation significantly impacts performance. In August, the detection efficiency of the PPI mode dropped below 50% at 4 km, while the highest detection efficiency occurred in April, where performance remained above 50% at 7 km. This is associated with enhanced thermal and dynamic activity in the lower atmosphere. Low-cloud activity also affected the detection performance of the DBS mode. The daily variation in the detection range in April was more pronounced than in January, with the detection range generally being larger. The increase in detection range was related to the more active vertical atmospheric mixing. The PPI mode was more sensitive to changes in meteorological factors, with its median detection range being 0.2-0.6 km shorter than that of the DBS mode when the meteorological optical range (MOR) was less than 4 km. Additionally, the PPI mode showed weaker stability than the DBS mode when relative humidity was below 75%. When relative humidity exceeded 80%, both modes showed a linear decrease in detection efficiency.