Observations of volcanic SO<sub>2</sub> from MLS on Aura

Abstract

Abstract. Sulfur dioxide (SO 2 ) is an important atmospheric constituent, particularly in the aftermath of volcanic eruptions. These events can inject large amounts of SO 2 into the lower stratosphere, where it is oxidised to form sulfate aerosols; these in turn have a significant effect on the climate. The MLS instrument on the Aura satellite has observed the SO 2 mixing ratio in the upper troposphere and lower stratosphere from August 2004 to the present, during which time a number of volcanic eruptions have significantly affected those regions of the atmosphere. We describe the MLS SO 2 data and how various volcanic events appear in the data. As the MLS SO 2 data are currently not validated we take some initial steps towards their validation. First we establish the level of internal consistency between the three spectral regions in which MLS is sensitive to SO 2 . We compare SO 2 column values calculated from MLS data to total column values reported by the OMI instrument. The agreement is good (within about 1 DU) in cases where the SO 2 is clearly at altitudes above 147 hPa.

Water vapour variability in the high-latitude upper troposphere – Part 2: Impact of volcanic eruptions

“…Durant and Rose, 2009). An alternative method based on the ratio of water vapour to SO 2 and the known mass of emitted SO 2 would give a low bias for the magmatic water mass for these two studied eruptions because the emitted mass of SO 2 from these eruptions was unusually low (Pumphrey et al, 2015;Vernier et al, 2013;Nakamae et al, 2014;Sears et al, 2013). Volcanic emissions are known to be more variable in terms of SO 2 than water vapour (Pinto et al, 1989).…”

MIPAS observations of volcanic sulfate aerosol and sulfur dioxide in the stratosphere

“…The SO 2 masses used in the present modelling study are indicated in bold. (2015) 562 Pumphrey et al (2015) 1350 (±38) 215 hPa Pumphrey et al (2015) 571 ( Concerning the measured and modelled SO 2 masses after the eruptions of Kasatochi and Sarychev (Fig. 6), comparisons show that until about 1 month after the eruptions, the SO 2 mass is by far underestimated by MIPAS.…”

“…Höpfner et al (2015) the given total uncertainty is the sum of the uncertainties per altitude range (their Table 3). In the case of Pumphrey et al (2015) pressure levels are given. These represent the highest pressure used for vertical integration.…”

“…Increased interest in stratospheric sulfate aerosol is also connected to its potential use in climate engineering schemes (e.g. Niemeier and Timmreck, 2015;Rasch et al, 2008). The negative radiative effect of stratospheric aerosol (Andersson et al, 2015;Brühl et al, 2015;Ridley et al, 2014;Santer et al, 2014;Solomon et al, 2011;Vernier et al, 2011) is discussed as being one of the causes of the global warming "hiatus" experienced during the first decade of this century (Haywood et al, 2014;Santer et al, 2014;Fyfe et al, 2013).…”

Simulation study for the Stratospheric Inferred Winds (SIW) sub-millimeter limb sounder

“…For instance, ClO VMR frequently reaches 1.5 ppbv near 20 km during polar springtime due to the chlorine activation during the polar winter. The enhancement of SO 2 after strong volcanic eruption can also be measured (Pumphrey et al, 2015). EPP induced enhancement of NO x and HO x are an other example.…”