1. OMI Science Team Meeting 2008 Using A-Train synergy to determine the potential impact of volcanic degassing on climate S.A. Carn 1, J. Wang 2, N.A. Krotkov 3, K. Yang 3, A.J. Krueger 1 1.Joint Center for Earth Systems Technology (JCET), UMBC, Baltimore, MD 2.Dept. of Geosciences, University of Nebraska – Lincoln, Lincoln, NE 3.Goddard Earth Science and Technology (GEST) Center, UMBC, Baltimore, MD

2. OMI Science Team Meeting 2008 OverviewOverview Aura mission foci – ozone, air quality and climate Volcanic eruptions – important natural climate forcing OMI and A-Train – unprecedented observations of volcanic SO 2 and aerosol Combined satellite data/modeling study – direct radiative forcing of volcanic sulfate aerosol

3. OMI Science Team Meeting 2008 Motivation for SO 2 measurements Climate impacts Volcanic and aviation hazards Air quality and environmental hazards Source: IPCC, 2001

4. 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) Ash 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 Effects of volcanic emissions on the climate system Tropopause (8-17 km) TROPOSPHERE STRATOSPHERE

5. OMI Science Team Meeting 2008 Impacts of historic volcanic eruptions on climate Laki (Iceland), 1783-84; ~120 Tg SO 2 –‘Dry fogs’ across Europe –Severe winters across Asia and North America in 1783-84 Tambora (Indonesia), 1815; ~60 Tg SO 2 –Global average cooling of 0.5-0.7ºC for 3 years –‘Year without summer’ in 1816, summer frosts and snowfall in North America Krakatau (Indonesia), 1883; ~40 Tg SO 2 –Global average cooling of 0.3-0.4ºC for >1 year Pinatubo (Philippines), 1991; ~20 Tg SO 2 –Global average cooling of ~0.5-0.7ºC –7% reduction in total column Ozone

6. OMI Science Team Meeting 2008 TOMS Volcanic SO 2 Emissions Inventory Only Pinatubo (1991) and El Chichon (1982) linked to measurable climate impacts El Chichon Pinatubo OMI

7. OMI Science Team Meeting 2008 Global SO 2 burden from OMI: Sep 2004 - Oct 2007 Sierra Negra Soufriere Hills Nyamulagira Rabaul P. Fournaise Manam Anatahan

8. Bottom-up inventory of global sulfur emissions Volcanic Marine and terrestrial DMS Biomass burning Fossil fuel use and industry Explosive (E) Passive (P) [Graf et al., 1997; Andres & Kasgnoc, 1998]

9. OMI Science Team Meeting 2008 Long-range transport of SO 2 clouds: Soufriere Hills, May 2006 HYSPLIT trajectory (13 days at 20 km) [Carn et al., ACPD, 2007] Soufriere Hills, Montserrat

10. OMI Science Team Meeting 2008 OMI average SO 2 for 2005: W. Pacific/S.E. Asia Anatahan (CNMI) Ambrym (Vanuatu) Manam (PNG) Bagana (PNG) China

11. OMI Science Team Meeting 2008 Comparing emission inventories with measurements Data for 1970s-1997 from GEIA database [Andres & Kasgnoc, 1998] OMI measurements improve on current SO 2 emission inventories GEIA - 1997OMI - 2005

12. OMI - SO 2, aerosols, BrO TES - SO 2, HCl MLS - strat. SO 2, HCl MODIS - SO 2, ash, sulfate AIRS - UTLS SO 2, aerosols, SO 2 profile? CALIPSO - cloud height, aerosol type Exploiting A-Train synergy for volcanic cloud studies

13. OMI Science Team Meeting 2008 Aura/OMI – Aura/MLS: Manam (PNG), Jan 2005 OMI SO 2 MLS SO 2 Manam MLS SO 2 profile MLS HCl profile Estimate stratospheric chlorine input

14. OMI Science Team Meeting 2008 AIRS 19:55 UT Aura/OMI - Aqua/AIRS: Sierra Negra (Galapagos) 2005 OMI 20:10 UT S. Negra Lower tropospheric SO 2 Sierra Negra (Galapagos) eruption, October 24, 2005 OMI-AIRS synergy indicates SO 2 concentrated in the lower troposphere F. Prata, NILU

15. OMI Science Team Meeting 2008 OMI - Aqua/AIRS - CALIPSO: Chaitén (Chile), May 2008 [Carn et al., EOS, in prep.] Chaitén AIRS SO 2 May 7, 0442 UT OMSO2 May 6, 1925 UT OMSO2 May 7, 1650 UT 16 km CALIPSO May 7, 0430 UT

16. OMI Science Team Meeting 2008 Proposed EOS data – modeling study A Combined EOS Data and GEOS-Chem Modeling Study of the Direct Radiative Forcing of Volcanic Sulfate Aerosols –NASA Modeling, Analysis and Prediction (MAP) program 2008 –PIs: J. Wang (UNL), S.A. Carn Rationale –Direct radiative forcing of volcanic sulfate aerosol poorly understood, particularly its spatiotemporal variability [IPCC, 2007] –Negative forcing of anthropogenic origin will decline –Large uncertainties on composition, phase and size of sulfate particles in mid- and upper troposphere [IPCC, 2007] –OMI and A-Train: unprecedented volcanic SO 2 observations –New iterative OMI SO 2 -O 3 algorithm for large eruptions –GEOS-Chem: 3D global atmospheric chemistry model –Updated sulfate aerosol module implemented in GEOS-Chem

17. OMI Science Team Meeting 2008 Sulfate aerosol phase transition and radiative forcing solid aqueous Phase transition Radiative forcing Sulfate radiative forcing dependent on composition, phase and RH Aircraft data indicate neutralization of sulfate by NH 3 above 5 km Sulfate phase transition module implemented in GEOS-Chem [Wang et al., 2008] – disregarded by most GCMs/CTMs Crystallization RH Deliquescence RH

18. OMI Science Team Meeting 2008 ApproachApproach Use OMI volcanic SO 2 data to drive GEOS-Chem CTM –New top-down volcanic SO 2 emission inventory for CTM community –Include SO 2 loading and altitude –Include TOMS SO 2 data for 1979-2005 Supplement OMI SO 2 data with AIRS and MLS SO 2 data –Information on SO 2 vertical profile; nighttime eruptions Use GEOS-Chem to model sulfate aerosol distribution, phase, composition and optical properties –Calculate direct radiative forcing of volcanogenic sulfate aerosol Compare model results with aerosol data from OMI, MODIS, CALIPSO, MISR –Validate model using eruption case studies –Refine SO 2 emission inventory

19. OMI Science Team Meeting 2008 Aqua MODIS: Oct 7 Eruption example: Rabaul (PNG), Oct 7, 2006 Oct 7 Oct 8 Oct 9 Total SO 2 : ~0.3 Tg

20. OMI Science Team Meeting 2008 GEOS-Chem simulation: Rabaul (PNG), Oct 9, 2006 OMSO2: 9 Oct Eruption on Oct 7

21. OMI Science Team Meeting 2008 Aerosol data: Rabaul (PNG), Oct 2006 Aqua MODIS AOT: 8-9 Oct CALIPSO Backscatter: 14 Oct MISR AOT: 8-9 Oct OMAERO: 8 Oct OMSO2: 8 Oct

22. OMI Science Team Meeting 2008 SummarySummary Volcanic eruptions are a major cause of natural climate forcing –Major climate forcing eruptions occur ~1-2 times per century –Background of frequent smaller eruptions OMI and the A-Train are providing unprecedented measurements of volcanic SO 2 and aerosol –Near 100% detection rate during normal operations –A-Train synergy provides altitude information Sulfate particle phase transition incorporated in GEOS-Chem model –Accurate simulation of sulfate phase and optical properties Unique opportunity to study the direct radiative forcing of volcanic sulfate aerosol –New top-down SO 2 emission inventory will be developed for the CTM community

24. Bottom-up inventory of global sulphur emissions Volcanic Marine and terrestrial DMS Biomass burning Fossil fuel use and industry Explosive 0.5-4 % Moderate Passive 5-10 % Low 18 % Low 2 % Low 66 % Moderate TOTAL: ~100 Tg/yr LOSU [Graf et al., 1997; Andres & Kasgnoc, 1998] 36 25 2 37 Sulfate burden

25. OMI Science Team Meeting 2008 Detection of passive degassing with OMI: SW Pacific Mariana Is Papua New Guinea Solomon Is Vanuatu Volcanic SO 2 plumes in PBL

26. OMI Science Team Meeting 2008 Aura/OMI - CALIPSO lidar: Soufriere Hills, May 2006 May 20 eruption on Montserrat SO 2 tracked for 3 weeks Cloud altitude ~20 km Aerosol layer non-depolarizing Sulfate dominant, not ash [Credit: CALIPSO Team, NASA Langley] [Carn et al., ACPD, 2007] CALIPSO ‘first light’ - 7 June 2006 OMI SO 2 - 7 June 2006