Recent Anthropogenic Increases in Sulfur Dioxide from Asia Have - PowerPoint PPT Presentation

1 Recent Anthropogenic Increases in Sulfur Dioxide from Asia Have Minimal Impact on Stratospheric Aerosol Ryan R. Neely III, O. Brian Toon, Susan Solomon, J. P . Vernier, C. Alvarez, J. M. English, K. H. Rosenlof, M. J. Mills,C. G. Bardeen, John S. Daniel, Jeffrey P . Thayer Acknowledgments: P . Yu, H. L. Miller, J. E. Barnes Neely et al. (2013), Recent anthropogenic increases in SO 2 from Asia have minimal impact on stratospheric aerosol, GRL, 40, doi:10.1002/grl.50263.

2000 to 2010 is an unprecedented “background” period n o i s s Fuego i m s n a r T Clear Sky Transmission At Mauna Loa, HI indicates “background” stratospheric aerosol conditions since 1998.

GMD Lidar observations reveal variability in “background” stratospheric aerosol Mauna Loa, HI Boulder, CO t +6.3%/yr +4.8%/yr 20 to 25 km 20 to 25 km Adapted from Hofmann at al. (2009)

A “Trend” In Global Stratospheric Aerosol? Northern Mid-Latitudes Tropics Trends 4-7%/yr Southern Mid-Latitudes Adapted from Vernier, J. P. et al. Major influence of tropical volcanic eruptions on the stratospheric aerosol layer during the last decade. Geophys. Res. Lett 38, L12807– (2011).

5 Variability in stratospheric aerosol impacts global radiative forcing Total Radiative Forcing 2.0 GISS + no strat. aerosols after 2000 Greenhouse Gases and Tropospheric Aerosols only No strat. aerosols 1.5 “Background” Stratospheric Projections Aerosol (No Volcanoes) "Background" W/m 2 1.0 Satellite Observed Stratospheric Aerosol Record after Pinatubo Pinatubo 0.5 El Chichon GISS Bern 2.5cc 0.0 1980 1990 2000 2010 2020 Greenhouse gas forcing increased continuously throughout period. Stratospheric aerosol only slowed increase by ~0.2W/m 2 Adapted from Solomon et al. (2011), The Persistently Variable “Background” Stratospheric Aerosol Layer and Global Climate Change, Science . Adapted from Solomon et al. (2011), The Persistently Variable “Background” Stratospheric Aerosol Layer and Global Climate Change, Science .

Possible Theories for “Trends”: Asian Emissions? Global SO 2 Emissions ! 0.6% of Global Emissions 160,000 ! 140,000 ! must make it to stratosphere 120,000 ! to maintain sulfur burden Gg SO 2 ! 100,000 ! 80,000 ! (Hofmann et al. 2009) 60,000 ! 40,000 ! 20,000 ! 0 ! 1850 ! 1875 ! 1900 ! 1925 ! 1950 ! 1975 ! 2000 ! Year ! China SO 2 Emissions ! 40,000 ! 35,000 ! 30,000 ! 25,000 ! Gg SO 2 ! 20,000 ! 15,000 ! 10,000 ! 5,000 ! 0 ! 1900 ! 1925 ! 1950 ! 1975 ! 2000 ! Year ! Adapted from Smith, S. J., J. van Aardenne, Z. Klimont, R. J. Andres, A. Volke, and S. Delgado Arias (2011), Anthropogenic sulfur dioxide emissions: 1850–2005, Atmos. Chem. Phys, 11(3), 1101–1116, doi:10.5194/acp-11-1101-2011.

Possible Theories for “Trends”: Moderate Volcanoes? Adapted from Vernier, J. P. et al. Major influence of tropical volcanic eruptions on the stratospheric aerosol layer during the last decade. GRL 38, L12807– (2011).

Current observations cannot partition the observed variability to sources

9 The Model CARMA 4 x 36 Bins 0.2 nm to 1100 nm Meteoritic Smoke, Pure Sulfates, Mixed Sulfates Adapted from English et al. (2011) Neely, R. R., III, J. M. English, O. B. Toon, S. Solomon, M. Mills, and J. P. Thayer (2011), Implications of extinction due to meteoritic smoke in the upper stratosphere, Geophys. Res. Lett, 38(24), doi:10.1029/2011GL049865.

10 Model Experiment Setup: SO 2 Schemes Anthropogenic Volcanic Spin-Up Base: 2000 Repeating 5 model years 10 model years “ 2010 ” “1995” “2000”

11 Volcanoes drive stratospheric aerosol variability Tropics 20 N to 20 S, 20 to 30 km − − 20 S − 20 N, 20 to 30 km − 3 6 6 x 10 Base Model Run 1 Base Model Run 1 5.5 Base Model Run 2 5.5 Base Model Run 2 Base Model Run 3 Base Model Run 3 Anthropogenic Emissions Run 1 Anthropogenic Emissions Run 1 5 5 Anthropogenic Emissions Run 2 Anthropogenic Emissions Run 2 10x Anthropogenic Emissions 4.5 10x Anthropogenic Emissions 4.5 AOD (525 nm) Volcanic Emissions Volcanic Emissions SAGE II and Calipso AOD AOD 525nm 4 SAGE II and Calipso AOD 4 Volcanic Eruptions Volcanic Eruptions 3.5 3 2.5 2 1.5 Ul RuRa At Ma Si So Ta Jb ChOkKa Sa 1 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 Month Year

12 Anthropogenic emissions may have some influence Northern Midlatitudes 30 N to 50 N, 15 to 30 km − − 30 N − 50 N, 15 to 30 km − 3 10 x 10 6 Base Model Run 1 Base Model Run 1 5.5 Base Model Run 2 Base Model Run 2 9 Base Model Run 3 Base Model Run 3 Anthropogenic Emissions Run 1 Anthropogenic Emissions Run 1 5 Anthropogenic Emissions Run 2 8 Anthropogenic Emissions Run 2 10x Anthropogenic Emissions 10x Anthropogenic Emissions 4.5 AOD (525 nm) Volcanic Emissions Volcanic Emissions 7 SAGE II and Calipso AOD AOD 525nm SAGE II and Calipso AOD 4 Volcanic Eruptions Volcanic Eruptions 6 5 4 3 Sa Ul RuRa At Ma Si So Ta Jb ChOkKa 2 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 Year Year

13 Anthropogenic Influence: The Asian Tropical Aerosol Layer (ATAL) Median 1020 nm Extinction Ratio Observed by SAGE II from 15N to 45N, June thru August Plot adapted from Thomason, L. W. and Vernier, J.-P .: Improved SAGE II cloud/aerosol categorization and observations of the asian tropopause aerosol layer: 1989–2005, Atmos. Chem. Phys. Discuss., 12, 27521-27554, doi:10.5194/acpd-12-27521-2012, 2012.

14 Anthropogenic Influence: The ATAL Modeled Mean 1020 nm Extinction Ratio from 14N to 46N, June thru August Without Chinese and Indian With Global Anthropogenic Sulfur Emissions Anthropogenic Sulfur Emissions Altitude (km) ATAL reduced by ~60%and “Background” Layer is similar Longitude Longitude

15 Conclusions Stratospheric Aerosol Layer Volcanoes are the major source Anthropogenic SO 2 may variability be responsible for ATAL S O 2 S O S O 2 2 D M S Marine OCS Volcanic Anthropogenic Terrestrial

16 Back Up Slides

17 Anthropogenic Influence: The ATAL Modeled Mean 1020 nm Extinction Ratio from 14N to 46N, June thru August Without Global Anthropogenic Sulfur Emissions With Global Anthropogenic Sulfur Emissions Altitude (km) No ATAL present and “Background” Layer has 10% less extinction and Longitude Longitude

18 “Trends”: Volcanic or Anthropogenic? Aerosol Layer Stratosphere S O 2 S O Troposphere OCS 2 S O 2 OCS Surface Biomass Anthropogenic Volcanic Burning Terrestrial Marine

19 Increases in Asian Anthropogenic Emissions since 2000 25 Observed India Emissions 2000 Emissions totaled 25 Tg Observed Chinese Emissions SO 2 (Tg, Above 2000 Emissions ) 20 ~50 Increase 15 10 5 0 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 Year Data source: Lu, Z., Zhang, Q. & Streets, D. G. Sulfur dioxide and primary carbonaceous aerosol emissions in China and India. 1996–2010, Atmospheric Chemistry and Physics 11, 9839–9864 (2011).

20 Modeling volcanic emissions as plumes of SO 2 Manam (Ma) shown as an example Aura/OMI - 01/28/2005 04:12-04:16 UT - Orbit 02867 Eruption height: ~20 km OMI SO 2 SO 2 column STL [DU] 0 1 2 3 4 5 6 7 8 9 10 "The eruption...clearly penetrated into the stratosphere...based on the warmth of the central umbrella cloud, and the subsequent dispersion of the ice-cloud..." Andrew Tupper at the Darwin Volcanic Ash Advisory Centre

21 Modeling volcanic emissions as plumes of SO 2 Manam (Ma) shown as an example Monthly Averaged SO 2 WACCM SO 2 Profile Profile After Manam Eruption WACCM SO 2 Mixing Ratio at 19 km 40 35 30 Altitude (km) 25 20 15 10 5 0 0 0.01 0.02 SO 2 (Tg)

2000 to 2010 is an unprecedented “background” period Global Aerosol Optical Depth 0.020 0.020 Satellite (Global, >15 km) Satellite (Tropics, >15 km) 0.015 0.015 Optical Depth GISS Ammann et al. 0.010 0.010 0.005 0.005 0.000 0.000 1995 2000 2005 2010 Year Layer became stable only in 2000. Previous observations will be influenced by 1991 Pinatubo eruption. Adapted from Solomon et al. (2011), The Persistently Variable “Background” Stratospheric Aerosol Layer and Global Climate Change, Science Niwano et al. (2009), Seasonal cycles of Stratospheric Aerosol and Gas Experiment II near- background aerosol in the lower stratosphere, J. Geophys. Res, 114(D14), D14306.

23 Anthropogenic Influence: The Asian Tropical Aerosol Layer (ATAL) Mean Scattering Ratio (SR) from CALIPSO at 532 nm between 15–17 km Jun-Aug 2007 Jun-Aug 2006 Jun-Aug 2008 Jun-Aug 2009 Adapted from: Vernier, J. P ., L. W. Thomason, and J. Kar (2011), CALIPSO detection of an Asian tropopause aerosol layer, Geophys. Res. Lett, 38(7), doi:10.1029/2010GL046614.

Anthropogenic emissions transported to the stratosphere via the Asian Monsoon Plot from Randel et al. (2010), Asian Monsoon Transport of Pollution to the Stratosphere, Science .