In situ measurements of tropospheric volcanic plumes in Ecuador and Colombia during TC^sup 4

• Published in: Journal of geophysical research. Atmospheres 2011-05, Vol.116 (10), p.1B
• Main Authors: Carn, S A, Froyd, K D, Anderson, B E, Wennberg, P, Crounse, J, Spencer, K, Dibb, J E, Krotkov, N A, Browell, E V, Hair, J W, Diskin, G, Sachse, G, Vay, S A
• Format: Article
• Language: English
• Subjects: Acidity; Aerosols; Atmospheric chemistry; Emission measurements; Geophysics; In situ measurement; Instrumentation; Monitoring instruments; Plumes; Sulfates; Sulfur dioxide; Troposphere; Volcanoes
• ISSN: 2169-897X; 2169-8996

A NASA DC-8 research aircraft penetrated tropospheric gas and aerosol plumes sourced from active volcanoes in Ecuador and Colombia during the Tropical Composition, Cloud and Climate Coupling (TC^sub 4^) mission in July-August 2007. The likely source volcanoes were Tungurahua (Ecuador) and Nevado del Huila (Colombia). The TC^sub 4^ data provide rare insight into the chemistry of volcanic plumes in the tropical troposphere, and permit a comparison of SO2 column amounts measured by the Ozone Monitoring Instrument on the Aura satellite with in situ SO2 measurements. Elevated concentrations of SO2, sulfate aerosol, and particles were measured by DC-8 instrumentation in volcanic outflow at altitudes of 3-6 km. Estimated plume ages range from ∼2 h at Huila to ∼22-48 h downwind of Ecuador. The plumes contained sulfate-rich accumulation mode particles that were variably neutralized and often highly acidic. A significant fraction of supermicron volcanic ash was evident in one plume. The TC^sub 4^ data set provides further evidence of the impact of volcanic emissions on tropospheric acidity and oxidizing capacity.