Analysis of the spatial and temporal distribution characteristics of AOD in typical industrial cities in northwest China and the influence of meteorological factors

Abstract

The spatiotemporal distribution characteristics of AOD in Lanzhou City over the past decade, as well as the influence of meteorological factors, were analyzed using the MODIS MCD19A2 dataset from 2011 to 2022. Spatial Distribution: The annual average AOD in the study area was found to be 0.278. High AOD values were observed in the main urban area and surrounding low-altitude regions, while low AOD values were observed in the high-altitude mountainous areas in the northwest and southeast. The main urban area exhibited significantly higher AOD levels compared to the three surrounding counties. Temporal Trends: Influenced by air pollution control policies, the AOD in Lanzhou City started decreasing notably from 2014, with a total decrease of −27.18%. The overall trend displayed fluctuations and a downward pattern. The seasonal variation of AOD in Lanzhou City was evident, with the order of magnitude being spring > winter > autumn > summer. The AOD in Yuzhong County was particularly high in spring. There is spatial heterogeneity in the impact of meteorological factors on AOD in Lanzhou. Temperature exhibits greater significance in the central part of Lanzhou, while precipitation shows greater significance in the eastern part of the city, and wind speed is notably significant in the western and eastern parts of Lanzhou. Temperature, relative humidity, and wind speed are positively correlated with AOD, while precipitation and atmospheric pressure are negatively correlated with AOD. Three primary sets of interacting factors were identified: temperature and wind speed, temperature and relative humidity, and temperature and precipitation.