A 25-year assessment of aerosol dynamics and environmental drivers in Iran's Lakes and wetlands

This paper investigates the spatiotemporal patterns of aerosol optical depth (AOD) over 25 wetlands and lakes in Iran during the period 2000-2024. Monthly AOD values were integrated with climate and terrestrial variables. Trend analysis was performed using the Hamed-Rao Mann-Kendall test and Sen's slope estimator. The results indicated that AOD increased by 8 and 12% over Iran's water bodies in winter and autumn, respectively, while no significant increasing trends were observed in spring and summer. Annually, 8% of Iranian wetlands faced a significant increasing trend in AOD, which mostly occurred over the Jazmourian and Sheedvar wetlands (Z > 2.5). Seasonally, a notable increasing trend occurred over the Amirkelayeh, Parishan, and Mighan wetlands, as well as Lake Urmia (Z > 3). Using Random Forest and XGBoost models combined with SHAP analysis, it was determined that AOD changes were primarily associated with wind speed and vegetation cover in Jazmourian, and with salinity and soil moisture in the Parishan wetland. Terrestrial factors (80.3%) had a greater contribution to the degradation of air quality in both wetlands compared to climatic factors (19.7%). These findings are useful for understanding the synergy between natural and anthropogenic factors governing air quality in aquatic ecosystems in Iran.