Transport of anthropogenic and biomass burning aerosols from Europe to the Arctic during spring 2008

Louis Marelle (1) , Jean-Christophe Raut (1) , Jennie L. Thomas (1) , Kathy S. Law (1) , Boris Quennehen (1) , Gérard Ancellet (1) , Jacques Pelon (1) , Alfons Schwarzenboeck (2) , J. D. Fast (3)

1 TROPO - LATMOS
2 LaMP - Laboratoire de météorologie physique
3 PNNL - Pacific Northwest National Laboratory

During the POLARCAT-France airborne campaign in April 2008, pollution originating from anthropogenic and biomass burning emissions was measured in the European Arctic. We compare these aircraft measurements with simulations using the WRF-Chem model to investigate model representation of aerosols transported from Europe to the Arctic. Modeled PM2.5 is evaluated using EMEP measurements in source regions and POLARCAT aircraft measurements in the Scandinavian Arctic, showing a good agreement, although the model overestimates nitrate and underestimates organic carbon in source regions. Using WRF-Chem in combination with the Lagrangian model FLEXPART-WRF, we find that during the campaign the research aircraft sampled two different types of European plumes: mixed anthropogenic and fire plumes from eastern Europe and Russia transported below 2 km, and anthropogenic plumes from central Europe uplifted by warm conveyor belt circulations to 5–6 km. Both modeled plume types had significant wet scavenging (> 50% PM10) during transport. Modeled aerosol vertical distributions and optical properties below the aircraft are evaluated in the Arctic using airborne LIDAR measurements. Evaluating the regional impacts in the Arctic of this event in terms of aerosol vertical structure, we find that during the 4 day presence of these aerosols in the lower European Arctic (< 75° N), biomass burning emissions have the strongest influence on concentrations between 2.5 and 3 km altitudes, while European anthropogenic emissions influence aerosols at both lower (~1.5 km) and higher altitudes (~4.5 km). As a proportion of PM2.5, modeled black carbon and SO4= concentrations are more enhanced near the surface. The European plumes sampled during POLARCAT-France were transported over the region of springtime snow cover in Northern Scandinavia, where they had a significant local atmospheric warming effect. We find that, during this transport event, the average modeled top of atmosphere (TOA) shortwave direct and semi-direct radiative effect (DSRE) north of 60° N over snow and ice-covered surfaces reaches +0.58 W m−2, peaking at +3.3 W m−2 at noon over Scandinavia and Finland.

Domaines: Sciences de l'environnement; Milieux et Changements globaux; Physique Atmosphérique et Océanique [physics.ao-ph]

Louis Marelle, Jean-Christophe Raut, Jennie L. Thomas, Kathy S. Law, Boris Quennehen, et al.. Transport of anthropogenic and biomass burning aerosols from Europe to the Arctic during spring 2008. Atmospheric Chemistry and Physics, 2015, 15 (7), pp.3831-3850. ⟨10.5194/acp-15-3831-2015⟩. ⟨hal-01084080⟩