Climate Change: The Next Generation: "Major influence of tropical volcanic eruptions on the stratospheric aerosol layer during the last decade" by J.-P. Vernier et al., Geophys. Res. Lett., 38 (2011); doi: 10.1029/2011GL047563

Tuesday, July 19, 2011

"Major influence of tropical volcanic eruptions on the stratospheric aerosol layer during the last decade" by J.-P. Vernier et al., Geophys. Res. Lett., 38 (2011); doi: 10.1029/2011GL047563

Geophysical Research Letters, 38 (2011) L12807; doi: 10.1029/2011GL047563

Major influence of tropical volcanic eruptions on the stratospheric aerosol layer during the last decade

Key Points

Minor tropical volcanic eruptions: important source of stratospheric aerosols
Stratospheric aerosol layer mainly impacted by those events
Potential impacts on climate and ozone chemistry

J.-P. Vernier (NASA Langley Research Center, Hampton, VA, USA, and LATMOS, CNRS, INSU, Université de Versailles Saint Quentin, Université de Paris 6, Guyancourt, France), L. W. Thomason (NASA Langley Research Center, Hampton, VA, USA), J.-P. Pommereau (LATMOS, CNRS, INSU, Université de Versailles Saint Quentin, Université de Paris 6, Guyancourt, France), A. Bourassa (Institute of Space and Atmospheric Studies, University of Saskatchewan, Saskatoon, Saskatchewan, Canada), J. Pelon, A. Garnier, and A. Hauchecorne (LATMOS, CNRS, INSU, Université de Versailles Saint Quentin, Université de Paris 6, Guyancourt, France), L. Blanot (LATMOS, CNRS, INSU, Université de Versailles Saint Quentin, Université de Paris 6, Guyancourt, and ACRI-ST, Sophia-Antipolis, France), C. Trepte (NASA Langley Research Center, Hampton, VA, USA), Doug Degenstein (Institute of Space and Atmospheric Studies, University of Saskatchewan, Saskatoon, Saskatchewan, Canada) and F. Vargas (Institute for Research and Development, Paraíba Valley University, São José dos Campos, Brazil)

Abstract

The variability of stratospheric aerosol loading between 1985 and 2010 is explored with measurements from SAGE II, CALIPSO, GOMOS/ENVISAT, and OSIRIS/Odin space-based instruments. We find that, following the 1991 eruption of Mount Pinatubo, stratospheric aerosol levels increased by as much as two orders of magnitude and only reached “background levels” between 1998 and 2002. From 2002 onwards, a systematic increase has been reported by a number of investigators. Recently, the trend, based on ground-based lidar measurements, has been tentatively attributed to an increase of SO₂ entering the stratosphere associated with coal burning in Southeast Asia. However, we demonstrate with these satellite measurements that the observed trend is mainly driven by a series of moderate but increasingly intense volcanic eruptions primarily at tropical latitudes. These events injected sulfur directly to altitudes between 18 and 20 km. The resulting aerosol particles are slowly lofted into the middle stratosphere by the Brewer-Dobson circulation and are eventually transported to higher latitudes.