title: Significant radiative impact of volcanic aerosol in the lowermost stratosphere.
abstract: Despite their potential to slow global warming, until recently, the radiative forcing associated with volcanic aerosols in the lowermost stratosphere (LMS) had not been considered. Here we study volcanic aerosol changes in the stratosphere using lidar measurements from the NASA CALIPSO satellite and aircraft measurements from the IAGOS-CARIBIC observatory. Between 2008 and 2012 volcanism frequently affected the Northern Hemisphere stratosphere aerosol loadings, whereas the Southern Hemisphere generally had loadings close to background conditions. We show that half of the global stratospheric aerosol optical depth following the Kasatochi, Sarychev and Nabro eruptions is attributable to LMS aerosol. On average, 30% of the global stratospheric aerosol optical depth originated in the LMS during the period 2008-2011. On the basis of the two independent, high-resolution measurement methods, we show that the LMS makes an important contribution to the overall volcanic forcing.
authors.affiliation: Department of Physics, Lund University, P.O. Box 118, Lund 22100, Sweden.
authors.forename: Sandra M
authors.initials: SM
authors.lastname: Andersson
authors.affiliation: Department of Physics, Lund University, P.O. Box 118, Lund 22100, Sweden.
authors.forename: Bengt G
authors.initials: BG
authors.lastname: Martinsson
authors.affiliation: 1] Science Systems and Applications, Inc., Parkway, Suite 200, Hampton, Virginia 23666, USA [2] NASA Langley Research Center, 11 Langley Boulevard, Hampton, Virginia 23681, USA.
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: Vernier
authors.affiliation: Department of Physics, Lund University, P.O. Box 118, Lund 22100, Sweden.
authors.forename: Johan
authors.initials: J
authors.lastname: Friberg
authors.affiliation: Max Planck Institute for Chemistry, Department of Atmospheric Chemistry, Hahn-Meitner Weg 1, Mainz 55128, Germany.
authors.forename: Carl A M
authors.initials: CA
authors.lastname: Brenninkmeijer
authors.affiliation: Leibniz Institute for Tropospheric Research, Department of Experimental Aerosol and Cloud Microphysics, Permoserstrasse 15, Leipzig 04318, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Hermann
authors.affiliation: Royal Netherlands Meteorological Division of Chemistry and Climate, Climate Research, P.O. Box 201, De Bilt 3730AE, The Netherlands.
authors.forename: Peter F J
authors.initials: PF
authors.lastname: van Velthoven
authors.affiliation: Institute for Meteorology and Climate Research, Atmospheric Trace Gases and Remote Sensing, Karlsruhe Institute of Technology (KIT), P.O. Box 3640, Karlsruhe 76021, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Zahn