Atmospheric aerosols in the Southern European Alps: Long-term SKYNET observations and synergy with AERONET at the Aosta–Saint-Christophe station, Italy

Quantifying variations of the aerosol load and characteristics in the Southern European Alps is crucial for distinguishing local from Po Basin and broader synoptic contributions. This work presents long-term observations from the Aosta-Saint Christophe Observatory (570 m a.s.l.), focusing on the analysis of the SKYNET Prede POM-02 dataset (operational since 2012) and its synergy with a recently installed AERONET Cimel CE318-TS9 (since 2023). We present long-term aerosol trends derived from the POM series and discuss their relationship with air quality policies and atmospheric circulation changes. Furthermore, we analyze the consistency between SKYNET and AERONET products during the overlapping period, discussing harmonization procedures in light of instrumental differences and retrieval assumptions. The ultimate aim is to derive a harmonized climatology to establish a robust baseline for the region and to support future experimental campaigns deploying distributed photometers to investigate aerosol gradients across the Alpine valley.