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

Carn, S. A. and Froyd, K. D. and Anderson , B. E. and Wennberg, P. and Crounse, J. and Spencer, K. and Dibb, J. E. and Krotkov, N. A. and Browell, E. V. and Hair, J. W. and Diskin, G. and Sachse, G. and Vay, S. A. (2011) In situ measurements of tropospheric volcanic plumes in Ecuador and Colombia during TC^4. Journal of Geophysical Research D, 116 . Art. No. D00J24. ISSN 0148-0227. http://resolver.caltech.edu/CaltechAUTHORS:20110527-115645829

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Abstract

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^4) mission in July–August 2007. The likely source volcanoes were Tungurahua (Ecuador) and Nevado del Huila (Colombia). The TC^4 data provide rare insight into the chemistry of volcanic plumes in the tropical troposphere and permit a comparison of SO_2 column amounts measured by the Ozone Monitoring Instrument (OMI) on the Aura satellite with in situ SO_2 measurements. Elevated concentrations of SO_2, 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. In-plume O_3 concentrations were ~70%–80% of ambient levels downwind of Ecuador, but data are insufficient to ascribe this to O_3 depletion via reactive halogen chemistry. The TC^4 data record rapid cloud processing of the Huila volcanic plume involving aqueous-phase oxidation of SO_2 by H_2O_2, but overall the data suggest average in-plume SO_2 to sulfate conversion rates of ~1%–2% h^(−1). SO_2 column amounts measured in the Tungurahua plume (~0.1–0.2 Dobson units) are commensurate with average SO_2 columns retrieved from OMI measurements in the volcanic outflow region in July 2007. The TC^4 data set provides further evidence of the impact of volcanic emissions on tropospheric acidity and oxidizing capacity.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1029/2010JD014718DOIArticle
ORCID:
AuthorORCID
Wennberg, P.0000-0002-6126-3854
Crounse, J.0000-0001-5443-729X
Additional Information:© 2011 American Geophysical Union. Received 6 July 2010; accepted 16 February 2011; published 10 May 2011. We acknowledge NASA funding for Aura validation (contracts NNG06GJ02G and NNX09AJ40G). Mark Schoeberl spearheaded the effort to intercept the volcanic plumes during the TC4 science flights. We thank Santiago Arellano for assistance with flight planning and volcanic activity reports during the TC4 mission and Cynthia Twohy for providing CVI data. The NOAA Air Resources Laboratory is acknowledged for the provision of the HYSPLIT transport and dispersion model and READY website (http://www.arl.noaa.gov/ready.html). We thank R. S. Martin and an anonymous reviewer for thorough reviews that greatly improved the paper.
Funders:
Funding AgencyGrant Number
NASANNG06GJ02G
NASANNX09AJ40G
Subject Keywords:volcanic plumes; Ecuador; Colombia; sulfur dioxide; sulfate aerosol
Record Number:CaltechAUTHORS:20110527-115645829
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20110527-115645829
Official Citation:Carn, S. A., et al. (2011), In situ measurements of tropospheric volcanic plumes in Ecuador and Colombia during TC4, J. Geophys. Res., 116, D00J24, doi:10.1029/2010JD014718.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:23825
Collection:CaltechAUTHORS
Deposited By: Ruth Sustaita
Deposited On:31 May 2011 15:22
Last Modified:06 Apr 2017 23:32

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