1. Satellite Measurements of Volcanic SO 2 Emissions into the UTLS Simon A. Carn 1, Kai Yang 2,3, Nickolay A. Krotkov 3, and Fred J. Prata 4 1.Michigan Technological University, Houghton, MI, USA 2.University of Maryland, College Park, MD, USA 3.Laboratory for Atmospheres, NASA Goddard Space Flight Center, Greenbelt, MD, USA 4.Norwegian Institute for Air Research, Kjeller, Norway

2. Tropospheric aerosols (Lifetime  1-3 weeks) Passive SO 2  H 2 SO 4 Indirect Effects on Clouds Explosive NET COOLING Stratospheric aerosols (Lifetime  1-3 years) Ashfall Dissolved volatiles Exsolution Effects on cirrus clouds absorption (IR) IR Heating emission IR Cooling More Downward IR Flux Less Upward IR Flux forward scatter Enhanced Diffuse Flux Reduced Direct Flux Less Total Solar Flux Heterogeneous  Less O 3 depletion Solar Heating H 2 S SO 2 NET HEATING  H 2 SO 4 CO 2 H 2 O backscatter absorption (near IR) Solar Heating More Reflected Solar Flux HCl, BrO, ClO Effusive Gas scavenging? Effects of volcanic emissions on the climate system Tropopause (8-17 km) TROPOSPHERE STRATOSPHERE Original slide courtesy of A. Robock

3. UV satellite remote sensing of volcanic SO 2 1978-2005 Total Ozone Mapping Spectrometer (TOMS) 2004- Ozone Monitoring Instrument (OMI) 2012- Suomi NPP/OMPS SW Pacific April 23, 2006

4. UV satellite volcanic SO 2 emissions inventory (1978 – 2013) Increase in total explosive volcanic SO 2 emissions from 1997-2011 El Chichòn Pinatubo [Bluth et al., 1993; Carn et al., 2003] Nabro

5. Increase in tropical stratospheric AOD since 2000 Vernier et al., GRL, 2011 Solomon et al., Science, 2011 Increase linked to influence of tropical volcanic eruptions Hofmann et al., GRL, 2009 Pinatubo Ruiz

6. UV satellite volcanic SO 2 emissions inventory (1978 – 2013) El Chichon Pinatubo [Bluth et al., 1993; Carn et al., 2003] Nabro TROPICS

7. OMI - SO 2, NO 2, BrO TES - SO 2 MLS - strat. SO 2, HCl MODIS - SO 2, ash, sulfate AIRS - UTLS SO 2, ash CALIOP (lidar) - cloud altitude, aerosol phase The A-Train Aura (2004-) Aqua (2002-) CALIPSO (2006-) CPR (radar) – precipitation, hydrometeors CloudSat (2006-)

8. Soufriere Hills Rabaul MLS HCl MLS SO 2 OMI SO 2 2006 Nyamulagira

9. Okmok Kasatochi MLS HCl MLS SO 2 OMI SO 2 2008

10. Sarychev Peak Redoubt MLS HCl MLS SO 2 OMI SO 2 2009

11. Grimsvötn Nabro Nyamulagira MLS HCl MLS SO 2 OMI SO 2 2011 Cordon Caulle

12. MLS SO 2 2012 2013 Paluweh Popocatepetl?

13. Grimsvötn mammatus (May 2011) Photos by Jón Ólafur Fate of volcanic gases in eruption columns Gas scavenging on ash and hydrometeors

14. Sulfur budget of the Grimsvötn 2011 eruption OMI - May 22 May 23 May 24 MetOp/IASI – H 2 S May 22 L. Clarisse – LATMOS/ULB Sigmarsson et al., GRL, in review ~0.3 Tg SO 2 ~29 kt H 2 S H 2 S/SO 2 = ~0.1, similar to in- situ Icelandic gas samples ~15 kt S 2 ? ~120 kt S sequestered on ash 0.6 Tg SO 2 emitted; only 0.3 Tg reached UTLS 38% S scavenged cf. 20% [Textor et al., 2003]

15. Suomi-NPP/OMPS UV Sensors NP Nadir Mapper (NM): swath similar to OMI Limb instrument: Aerosol and Ozone profiles above tropopause

16. Suomi NPP/OMPS NM SO 2 data for Paluweh (Indonesia) Feb 4, 2013 Feb 5, 2013 HYSPLIT forward trajectory @ 17 km HYSPLIT forward trajectory @ 15 km Reported (ash) plume altitude = ~14 km Paluweh

17. Suomi NPP/OMPS NM data for Paluweh CALIPSO Vertical Feature Mask Stratospheric aerosol detection

18. Aura/OMI data for Paluweh CALIPSO Vertical Feature Mask Stratospheric aerosol detection ~0.03 Tg SO 2 -> 0.04 Tg H 2 SO 4 Only 0.01-0.02 Tg/S year required to explain post-2002 strat. AOD increase [Hoffman et al., 2009]

19. Direct retrieval of SO 2 altitude from UV radiances SO 2 altitude retrievals for 2008 Kasatochi eruption [Yang et al., JGR, 2010] SO 2 altitude directly retrieved from UV radiances Validate with CALIPSO, MLS Reprocessing of entire UV OMI- OMPS data archive planned (NASA MEaSUREs project)

20. Summary Long-term record of volcanic SO 2 emissions based on UV satellite measurements continues (TOMS, OMI, OMPS) –Increased SO 2 flux from explosive volcanism 1997-2011 –Consistent with observed stratospheric AOD trends –Less explosive volcanism in 2012-13 –A-Train data (MLS, CALIPSO) provides profile information New insights into sulfur gas scavenging in eruption columns –2011 Grimsvötn (Iceland) eruption: 50% of S scavenged Many small tropical eruptions inject SO 2 to tropopause level –SO 2 sufficient to sustain long-term increase in stratospheric AOD –Plume altitudes based on ash clouds may underestimate SO 2 altitude Direct UV SO 2 altitude retrievals now available –Reprocessing of all major eruptions planned to develop new altitude- resolved volcanic SO 2 climatology (NASA MEaSUREs) Acknowledgments: NASA funding (Aura Science Team, Atmospheric Chemistry Modeling and Analysis program, NPP Science Team, MEaSUREs)

22. Time-series of maximum MLS SO 2 and HCl 10 40 15 25 68 hPa 46 hPa HCl SO 2 Direct injection Monsoon

23. OMI SO 2 zonal means Noise 2011 2008 2009 Nabro Grimsvötn Okmok Kasatochi Sarychev Nabro was the largest tropical volcanic SO 2 emission since the 1991 Pinatubo eruption