Aircraft Measurements of Tropospheric Aerosol in Antarctica

Kurzfassung

To date, the knowledge on the properties, sources and transport pathways of aerosol in the Antarctic troposphere is still incomplete owing to the logistical difficulties in performing measurement programs in Antarctica and the sparseness of manned observation sites. One particular shortcoming for better understanding of aerosol properties, distribution and transport patterns is the lack of information on the aerosol vertical distribution in the Antarctic troposphere. To improve knowledge in this area, the AGAMES (Antarctic Trace Gas and Aerosol Airborne Measurement Study) aircraft field experiment was conducted in the Antarctic summer season December/January 2006/7. The AGAMES study constitutes the first ever airborne campaign in Antarctica using a comprehensive aerosol instrument package for study of tropospheric aerosol. The aircraft used in this study was the Dornier 228-200 turboprop aircraft (Polar 2) of the Alfred Wegener Institute for Polar and Marine Research (AWI) in Bremerhaven. Altogether 36 flights were performed mainly in two Antarctic areas, close to Neumayer and close to Syowa. The flights covered an altitude range up to ~7000 m. Here we report on results of aerosol microphysical properties, aerosol spatial variability and air mass origin based on the FLEXPART Lagrangian particle dispersion model. The aerosol size distribution was measured in the diameter range from 0.004 to 20 µm by a combination of instruments: four condensation particle counters, a Differential Mobility Particle Sizer (DMPS) system, and three optical particle counters, one in the cabin (Grimm model 7.309, size range 0.26-2.2 µm) and two under the wings (PMS PCASP-100X, size range 0.12-3 µm and FSSP-300, size range in this study 1-20 µm). We will discuss vertical gradients and variability of aerosol particles, as well as observations of particle formation events and compare the results to aerosol observations in the Arctic.