Study of Haze Boundary Layer Features Based on Multi-Source Data in Shihezi, China

Abstract

To reveal the temporal–spatial characteristics of air pollution during winter haze events on the north slope of the Tianshan mountains, a combined detection experiment was conducted in this study using a tethered airship, Lidar, and ground monitors from December 2019 to January 2020 in Shihezi. First, the boundary layer height (BLH) was calculated using the temperature, relative humidity, wind speed, and atmospheric pressure detected by the tethered airship; the BLHs were mainly distributed from 200 m to 450 m, with the visibility (V) mainly less than 3000 m. Subsequently, the temporal–spatial characteristics of the atmospheric pollutants were analyzed. The results show that during winter haze events, the temperature was mainly between −5 °C and −15 °C, and the relative humidity was between 60% and 75%, with a wind speed of less than 2 m/s. Moreover, the temperature difference (ΔT) within the BLH was basically greater than 0, except from 14:00 to 18:00, and a larger ΔT corresponded to a lower V and more severe pollution, which indicates that the sensible heat flux is very weak, and the atmospheric structure is very stable. Meanwhile, the PM2.5 and PM10 were mainly concentrated between 130 and 180 μg·m−3 and between 160 and 230 μg·m−3, respectively; the maximum PM2.5 and PM10 appeared at 11:00–13:00. Furthermore, the black carbon was distributed at 6–8 μg·m−3 and decreased significantly around the BLH. Moreover, the extinction coefficient (EC) had a negative correlation with the V, and the maximum of the EC was 9 km−1 when V was the minimum (less than 1500 m) from 10:00 to 11:00. Finally, the relationship between V and the air quality index (AQI) is constructed as AQI=456e−0.00061V. The conclusions obtained provide a reference for haze elimination and environmental governance of the locale.