Analysis of a Dust Weather Process over East Asia in May 2019 Based on Satellite and Ground-Based Lidar

In May 2019, a strong sandstorm occurred in northern China, which lasted for a relatively long time and impacted a large area. The optical properties, vertical distribution and the transmission of the dust aerosols are analyzed using the data from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) and the ground-based lidar (Asian Dust and aerosol lidar observation NETwork, AD-NET). At the same time, the track of this dust process is validated by the hourly data from the China Meteorological Data Service Center and the HYbird Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model. Combined with the air-quality data from the PRC State Environmental Protection Administration, the influence on air quality is also analyzed. In addition, the ERA-interim reanalysis data are used to analyze the causes of the dust weather. The results show that: (1) The sand-storm process can be mainly divided into two stages, with the first stage from May 10th to 12th and the second stage from 13th to 16th. (2) The dust aerosols exist at a high altitude of 5–10 km in the Pacific region, and the depolarization ratio and the color ratio of the dust are 0.14 and 1.29, respectively. (3) After the comprehensive analysis of the data from the satellite and ground-based lidar, it is found that the dust is transmitted to Jeju in South Korea and Fukuoka in Japan, and the dust aerosols contribute to the station dust observations on average of 39.25% and 35.43%, respectively. (4) The trends of the attenuation backscattering coefficients and the apparent ratios from the ground-based AD-NET data and the corresponding CALIOP satellite-based lidar data are similar. (5) During the dust process, the concentration of particle matters increases significantly. The maximum concentration of PM₁₀ surpasses 1500 μg m⁻³, which is about 30 times of the national first-level standard. On May 11th and 14th, the mean values of PM_2.5 and PM₁₀ are very high in Gansu Province, which reach 7 times and 12 times of the national first-level standard, respectively, while the ratio of PM₁₀ and PM_2.5 reaches above 6 at many places in Gansu Province and Xinjiang. (6) The low trough at the western Inner Mongolia deepens and extends to east, and the South Asia high moves steadily southward, which together bring the cold air southward. On May 14th, the instability stratification is strengthened, which leads to the outbreak of the dust weather.