Understanding the Impact of Aerosol Transport on the cloud glaciation temperature in the Arctic

The Arctic is experiencing a faster warming, known as the Arctic amplification, but climate projections are still uncertain due to the aerosol-cloud interactions (ACI). The impact of aerosols on glaciation temperature, acting as ice nucleating particles, is poorly understood, especially for aerosols from long-range transport. During transport, physico-chemical properties of aerosols evolve due to aging, complicating the quantification of their role.

This study considers satellite observations from POLDER and MODIS instruments with atmospheric chemistry model (GEOS-Chem) and reanalysis datasets (ERA5) to investigate the influence of aerosols on cloud properties and glaciation temperatures. Carbon monoxide (CO) is employed as a passive tracer to aerosols from combustion sources. GEOS-Chem is used to distinguish between biomass burning (BB) and anthropogenic (ANT) emissions and further identify the source regions of air parcels. Spatial and temporal co-localization of cloud, aerosol, and environmental parameter datasets is performed to assess the interplay between meteorological parameters and aerosol properties on cloud properties and on the glaciation process.

Our analysis reveals distinct impacts of aerosols from BB and ANT sources on the glaciation temperature. Preliminary results indicate that pollution plumes from BB are associated with an increase or decrease of about 1.7°C of the glaciation temperature depending on the source region, while ANT pollution plumes suggest an increase of the glaciation temperature between 1.5°C and 2.8°C depending on the transport of air parcels before interacting with the clouds. This work highlights the necessity of considering transport-induced changes in aerosol properties to improve our understanding of the ACI and Arctic climate dynamics.