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Future directions in tropospheric chemistry – what else besides climate change

Future directions in tropospheric chemistry – what else besides climate change. Daniel J. Jacob. Group photo (2013). Plume dispersion. Urban smog. Range of tropospheric chemistry problems. Ozone layer. Visibility. Disasters. CLIMATE!. Climate. Regional smog. Biogeochemical cycles.

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Future directions in tropospheric chemistry – what else besides climate change

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  1. Future directions in tropospheric chemistry – what else besides climate change Daniel J. Jacob Group photo (2013)

  2. Plume dispersion Urban smog Range of tropospheric chemistry problems Ozone layer Visibility Disasters CLIMATE! Climate Regional smog Biogeochemical cycles Acid rain GLOBAL > 1000 km LOCAL < 100 km REGIONAL 100-1000 km

  3. Plume dispersion Urban smog Range of tropospheric chemistry problems Ozone layer Visibility Disasters Regional smog Biogeochemical cycles Acid rain GLOBAL > 1000 km LOCAL < 100 km REGIONAL 100-1000 km

  4. Jennifer’s foray into ozone smog • Nitrogen oxides in the troposphere: • global and regional budgets (Logan, 1983) – 508 citations • The sensitivity of ozone to nitrogen oxides and hydrocarbons in regional ozone episodes (Sillman, Logan, Wofsy, 1990) • -283 citations • Ozone in rural areas of the United States (Logan, 1989) - 159 citations • Factors regulating ozone over the United States and its export to the global atmosphere (Jacob, Logan, et al. 1993) – 150 citations (1991) This report paved the way for NOx controls!

  5. Trend in 95th percentile daytime ozone, 1990-2010 Spring Summer • Decrease in eastern US driven by NOx emission controls; • Increase or flat in Intermountain West Cooper et al. [2012]

  6. 4th-highest annual maximum for daily 8-h average ozone,2008-2010 Intermountain West: The next ozone frontier! Current standard: 75 ppb Proposed standard: 60-70 ppb

  7. Surface ozone at Gothic, Colorado • Most ozone originates from outside N America • Peak events of stratospheric influence cannot be reproduced by model • Zhang et al., in prep. Numerical decay of a free tropospheric plume In GEOS-Chem Eulerian models have difficulty preserving gradients (layers)in divergent free tropospheric flow, in a way that cannot be readily fixed by increasing grid resolution or the accuracy of numerical scheme Rastigeyev et al. [2010]

  8. Ammonia emission and air pollution Observed NH4+wet deposition fluxes can constrain NH3 emission estimates NADP data (circles) and GEOS-Chem model after adjoint inversion April: fertilizer July: livestock kgN ha-1 month-1 Contribution of food export to annual PM2.5 (ammonium nitrate) GEOS-Chem sensitivity simulation Fabien Paulot (in prep.)

  9. Critical load exceedances for N deposition at US national parks Critical loads are 3-5 kg N ha-1 a-1 depending on ecosystem More deposition is expected to originate from ammonia in future Present and future (RCP) US emissions 2006 NOx NH3 2050 2006 Future exceedances driven by ammonia emissions 2050 RCP2.6 Ellis et al. [2013] Ellis et al. [2013]

  10. OMI formaldehyde 2005-2009 Next frontier for air pollution: Nigeria • Population: 270 million (+2.6% a-1) • GDP: $273 billion (+7% a-1) – oil! • Most natural gas is flared • >80% of domestic energy from biofuel, waste gas flaring! An unusual mix of very high VOCs, low NOx – What will happen as infrastructure develops? aerosol (AOD) NO2 HCHO glyoxal methane Lagos Port Harcourt SCIA MISR Eloise Marais [Harvard]

  11. Biogeochemical cycle of mercury ANTHROPOGENIC PERTURBATION: fuel combustion mining WATER-SOLUBLE VOLATILE oxidation Hg(II) Hg(0) lifetime ~6 months (months) volcanoes erosion ATMOSPHERE OCEAN/SOIL Hg(0) Hg(II) particulate Hg reduction biological uptake burial uplift SEDIMENTS

  12. History of global anthropogenic Hg emissions Large past (legacy) contribution from N. American and European emissions; Asian dominance is a recent phenomenon Streets et al. , 2011

  13. Global source contributions to Hg in present-day surface ocean from biogeochemical box model constrained with GEOS-Chemfluxes emissions pre-1850 natural • Human activity has increased 7x the Hg content of the surface ocean • Half of this human influence is from pre-1950 emissions • N America, Europe and Asia share similar responsibilities for anthropogenic Hg in present-day surface ocean ROW former USSR N America S America Europe Asia Amos et al., in press

  14. Disposal of Hg in commercial products:a missing component of the Hg biogeochemical cycle? Global production of commercial Hg peaked in 1970 Hannah Horowitz (Harvard)

  15. Liang et al. [2010] stratospheric Bry model (upper boundary conditions) STRATOSPHERE 36 TROPOSPHERE Global tropospheric Bry budget in GEOS-Chem (Gg Br a-1) Bry 3.2 ppt BrO 0.32 ppt 56 CH3Br Deposition 57 CH2Br2 lifetime 7 days 407 CHBr3 1420 (5-15) 7-9 ppt Marine biosphere Volcanoes Sea-salt debromination (50% of 1-10 µm particles) SURFACE Sea salt is the dominant global source but is released in marine boundary layer where lifetime against deposition is short; CHBr3 is major source in the free troposphere Parrella et al. [2012]

  16. Bromine chemistry improves simulation of 19th century surface ozone • Standard models without bromine are too high, peak in winter-spring; bromine chemistry corrects these biases • Implies that anthropogenic perturbation to global tropospheric ozone is larger than currently assumed Parrella et al. [2012]

  17. Elusive understanding of what controls tropospheric OH Lightning seems to be a major driver of OH variability (Murray, Logan, Jacob, 2013) LIS+OTD (satellite) lightning, 1995-2005 Tropical lightning interannual variability GEOS-Chem with climatological lightning GEOS-Chem with interannual lightning (LIS)

  18. selected in November 2012 for 2018 launch PI: Kelly Chance, Harvard-Smithsonian • Monitoring of tropospheric ozone (2 levels), aerosols, NO2, SO2, formaldehyde, glyoxal with 1-hour temporal resolution, 2-km spatial resoution • To be part of a geostationary constellation with other sensors observing Europe and East Asia TEMPO geostationary UV/Vis satellite instrument Next frontier in satellite observations of atmospheric composition! TEMPO Sentinel-4 GEMS

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