Chemistry and sources of atmospheric aerosols deposited in the Central Pyrenees in the period 2016–2023, with a focus on African dust events occurred during cold season

This study specifically investigates the geochemical characterization and the identification of primary sources of atmospheric aerosols deposited in the Ordesa y Monte Perdido National Park (PNOMP, Spanish Pyrenees) from 2016 to 2023. The primary objective is to unravel the sources of these aerosols, analyze their temporal variability, and discern the impact of certain aerosol types, especially African dust, on processes affecting the surrounding cryosphere. Methodologically, the study employs robust and established sampling and analysis techniques, including total aerosol deposition monitoring, widely accepted aerosol analysis methods, and the Positive Matrix Factorization (PMF) v5.0 source contribution model, which identifies key aerosol factors and sources, both natural and anthropogenic. Additionally, the study integrates air mass back-trajectories analysis, allowing for the identification of synoptic meteorological conditions associated with African dust intrusions. Between 10,3 and 19,5 % of the sets of back-trajectories computed from three different starting during the 2016–2023 period corresponded to configurations that facilitated the arrival of air masses from North Africa. During this period, the annual average contribution of African dust to total deposition was 12,8 g m−2 yr−1, accounting for 45 % of the overall input, underscoring the influence of this source compared to other aerosol contributions such as black carbon. These findings highlight the complex interplay between atmospheric transport, aerosol composition, and snowpack dynamics in high-mountain environments. This study ultimately demonstrates the importance of sustained monitoring and cross-disciplinary research to better understand how aerosol deposition on natural systems in combination with ongoing climate change in the Pyrenees and similar alpine systems.