Detection of aerosols in Antarctica from long-range transport of the 2009 australian wildfires
Résumé
We analyze the long‐range transport to high latitudes of a smoke particle filament originating from the extra‐tropics plume after the Australian wildfires colloquially known as ‘Black Saturday’ on February 7th 2009 and report the first Antarctic stratospheric lidar characterization of such aerosols. Using a high‐resolution transport/microphysical model, we show that the monitoring cloud/aerosol lidar instrument operating at the French Antarctic station Dumont d’Urville (DDU‐66°S‐140°E) recorded a signature of those aerosols. The 532 nm scattering ratio of this filament is comparable to typical moderate stratospheric volcanic plume, with values between 1.4 and 1.6 on the 1st and 3rd days of March above DDU station at around the 14 and 16 km altitude respectively.
A dedicated model is described and its ability to track down fine optical signatures is validated against Antarctic lidar elastic aerosol and DIAL ozone measurements. Using one month of tropical CALIOP data to support a relatively simple microphysical scheme, we report modeled aerosol presence above DDU station after advection of the aerosol size distribution. In situ measurements also report associated positive ozone anomaly.
This case study provides evidence that biomass burning events injecting significant amounts of material up to stratospheric altitudes can be transported towards high latitudes. We highlight a potential imprint of smoke particles on the Antarctic atmosphere over larger time scales. Any underestimation of the global impact of such deep particle transport will lead to uncertainties in modeling the associated chemical or radiative effects, especially in polar regions where specific microphysical and chemical processes take place.
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Jumelet-et-al-Antarctic Plume Paper - Revised.pdf (1.66 Mo)
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