First satellite identification of volcanic carbon monoxide

Abstract

Volcanic degassing produces abundant H 2 O and CO 2, as well as SO 2, HCl, H 2 S, S 2, H 2, HF, CO, and SiF 4. Volcanic SO 2, HCl, and H 2 S have been detected from satellites in the past; the remaining species are analyzed in situ or using airborne instruments, with all the consequent limitations in safety and sampling, and at elevated costs. We report identification of high CO concentrations consistent with a volcanic origin (the 2010 Eyjafjallajkull and 2011 Grímsvtn eruptions in Iceland) in data from the Measurements of Pollution in the Troposphere instrument (MOPITT) onboard EOS/Terra. The high CO values coincide spatially and temporally with ash plumes emanating from the eruptive centers, with elevated SO 2 and aerosol optical thickness, as well as with high CO values in data from the Infrared Atmospheric Sounding Interferometer (IASI), onboard MetOp-A. CO has a positive indirect radiative forcing; climate models currently do not account for volcanic CO emissions. Given global volcanic CO 2 emissions between 130 and 440 Tg/year and volcanic CO:CO 2 ratios from the literature, we estimate that average global volcanic CO emissions may be on the order of ∼5.5 Tg/year, equivalent to the CO emissions caused by combined fossil fuel and biofuel combustion in Australia. © 2012. American Geophysical Union. All Rights Reserved.