<p>“The impact of different aerosol optical thickness types (AOT-types) on pre-monsoon precipitation trends was analyzed using 40 years (1981–2020) of satellite precipitation and reanalysis (MERRA-2 and ERA5) datasets. The results, based on anomaly analysis and Mann-Kendall (MK) trend tests, indicate an increase in most AOT-types (Dust, Organic Carbon, Black Carbon, and Sea Salt) and a decrease in precipitation trends over most parts of Nigeria during the recent two decades (2001–2020). Dust (≈ 75%) was predominant, followed by Organic Carbon (≈ 12.5%) when averaged over the region. Statistical analysis revealed a significant relationship (p &lt; 0.05) between all AOT types and precipitation across the entire domain, with negative correlations observed primarily in areas where precipitation trends have decreased. The relationships between absorbing AOT types and cloud fraction (CFr) were not statistically significant in the southern region. The location and impact of different AOT types, and their varying statistical relationships with precipitation and CFr, are linked to increased recent activities at emission sources and atmospheric dynamics (relative humidity and wind fields). High-altitude regions exhibited distortions in precipitation and CFr patterns, which might contribute to their nonlinear relationships with AOT-types. The findings highlight the dominant role of dust and organic aerosols, suggesting positive climate feedback due to increasing global warming, as evidenced by the reported increase in precipitation in northern Nigeria and a decrease in the south. Additionally, the rising total AOT trend could potentially distort the actual monsoon events (i.e., onset, duration, and cessation) if not properly monitored.</p> Graphical Abstract <p>To the graphical snapshot, this study aims to quantify various aerosol optical thickness (AOT) types (Black Carbon (BC), Dust (DU), Organic Carbon (OC), Sea Salt (SS), and Sulfate (SU)) in relation to changes in pre-monsoon precipitation trends over 40 years (1981–2020) across Nigeria in West Africa. The Mann-Kendall (MK) test indicates a significant decreasing trend in precipitation over the region, particularly in the most recent two decades (2001–2020). During this period, the time series analysis of AOT and precipitation reveals an inverse relationship, where low precipitation values correspond to high AOT levels. The study also calculates AOT anomalies for both the earlier period (1981–2000) and the recent decades. Findings show positive anomalies in BC, DU, OC, and SS AOTs, while SU exhibits a negative anomaly during 2001–2020. Furthermore, the percentage contribution of different AOT types in the recent two decades highlights that Dust (≈ 75%) and Organic Carbon (≈ 25%) dominate aerosol loading during the pre-monsoon season. Latitudinal variations in AOT types, precipitation, and cloud cover illustrate the spatial distribution of aerosol emission sources, as well as the influence of orographic effects on precipitation and cloud properties. The study establishes statistically significant relationships and a strong negative correlation, particularly over the coast, between the AOT-types and changes in precipitation. Finally, the work shows that emission events and aerosol distribution are primarily governed by wind fields and moisture parameters in the lower troposphere. Insights from this study demonstrate that long-term changes in AOT anomalies can significantly influence pre-monsoon precipitation, potentially affecting the broader monsoon cycle.</p>