Abstract: As an important component of the atmosphere, aerosols significantly influence regional climate and environment through scattering and absorption of solar radiation. To reveal the spatiotemporal evolution patterns of aerosol optical properties in Liaoning Province, we analyzed the spatiotemporal distribution characteristics and evolution trends of aerosol optical depth (AOD) in Liaoning Province based on the reanalysis data of AOD from 1994 to 2023. The results showed that the annual average AOD from 1994 to 2023 in Liaoning Province exhibited a distribution pattern of higher values in the south and lower values in the north, with the southern and coastal areas being the high-value centers (average value 0.43), while that in the west and north were the lowest (0.30). From 1994 to 2012, the annual average AOD in Liaoning Province increased by 0.007, and it decreased by 0.011 from 2013 to 2023, confirming the critical role of national emission reduction policies in the long-term reduction of aerosols in the northeastern region. Due to the combined effects of spring dust weather, high-temperature and high-humidity conditions in summer, and the increase in aerosol hygroscopicity and boundary layer uplift the monthly scale AOD in Liaoning Province, which showed a single-peak distribution. From January to February, the AOD was at the lowest level of the year (0.20), reaching its peak in June (0.58), and returning to the low value area in winter from November to December. The summer aerosol load was about 2.9 times that of winter. The results could provide data support for consolidating the achievements of air quality improvement.

Key words: aerosol optical depth, spatial distribution, trend of change, Liaoning Province