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Current work on methane and tropospheric bromine Daniel J. Jacob

Current work on methane and tropospheric bromine Daniel J. Jacob. w ith Kevin Wecht , Alex Turner, Melissa Sulprizio , Johan Schmidt. Global methane trend (IPCC AR5). UCI AGAGE NOAA. Building a methane monitoring system for N America. EDGAR emission Inventory for methane.

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Current work on methane and tropospheric bromine Daniel J. Jacob

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  1. Current work on methane and tropospheric bromineDaniel J. Jacob with Kevin Wecht, Alex Turner, Melissa Sulprizio, Johan Schmidt

  2. Global methane trend (IPCC AR5) UCI AGAGE NOAA

  3. Building a methane monitoring system for N America EDGAR emission Inventory for methane Can we use satellites together with suborbital observations of methane to monitor methane emissions on the continental scale and test/improve emission inventories?

  4. Methane emission inventories for N. America: EDGAR 4.2 (anthropogenic), LPJ (wetlands) N American totals in Tg a-1 Previous top-down constraints from surface/aircraft observations have suggested factor of 2-3 underestimate in US emissions

  5. Methane observing system in North America Satellites AIRS, TES, IASI Thermal IR TROPOMI GCIRI 1-day geo GOSAT 3-day, sparse SCIAMACHY 6-day Shortwave IR 2002 2006 2009 20015 2018 Suborbital 1/2ox2/3o grid of GEOS-Chem chemical transport model (CTM) INTEX-A SEAC4RS CalNex

  6. High-resolution inverse analysis of methane emissions in North America Observations EDGAR 4.2 + LPJ a priori bottom-up emissions GEOS-Chem CTM and its adjoint 1/2ox2/3o over N. America nested in 4ox5o global domain Bayesian inversion Validation Verification Optimized emissions at 1/2ox2/3o resolution

  7. Testing GEOS-Chem methane background with HIPPO aircraft data across Pacific Aug-Sep11 Oct-Nov09 Jun-Jul11 Jan09 GEOS-Chem HIPPO Methane, ppbv Latitude, degrees Time-dependent boundary conditions are optimized iteratively as part of the inversion Alex Turner and Kevin Wecht, Harvard

  8. Optimization of methane emissions using SCIAMACHY data for Jul-Aug 2004 Concurrent INTEX-A aircraft mission allows validation of SCIAMACHY, evaluation of inversion SCIAMACHY column methane mixing ratio XCH4 INTEX-A methane below 850 hPa C. Frankenberg (JPL) D. Blake (UC Irvine) XCH4 INTEX-A validation profiles H2O correction to SCIAMACHY data SCIAMACHY Kevin Wecht, Harvard INTEX-A

  9. Optimized selection of emission clusters for adjoint inversion of SCIAMACHY data Optimal clustering of 1/2ox2/3ogridsquares Native resolution 1000 clusters 34 Optimized US anthropogenic emissions (Tg a-1) Correction factor to bottom-up emissions posterior cost function SCIAMACHY data cannot constrain emissions at 1/2ox2/3o resolution; use 1000 optimally selected clusters 28 Number of clusters in inversion 1 10 100 1000 10,000 Kevin Wecht, Harvard

  10. North American methane emission estimates optimized by SCIAMACHY data (Jul-Aug 2004) SCIAMACHY column methane mixing ratio Correction factors to priori emissions ppb 1700 1800 EDGAR v4.2 26.6 EPA 28.3 This work 32.7 US anthropogenic emissions (Tg a-1) Kevin Wecht, Harvard

  11. GOSAT methane column mixing ratios, Oct 2009-2010 Retrieval from U. Leicester

  12. Preliminary inversion of GOSAT Oct 2009-2010 methane Correction factors to prior emissions (EDGAR 4.2 + LPJ) Nested inversion with 1/2ox2/3o resolution Alex Turner, Harvard Next step: clustering of emissions in the inversion

  13. Testing the information content of satellite data with CalNex inversion of methane emissions Correction factors to EDGAR (analytical inversion) CalNex observations GEOS-Chem w/EDGAR v4.2 May-Jun 2010 S. Wofsy (Harvard) 1800 2000 ppb 0.1 1 3 2x underestimate of livestock emissions Emisssions, Tg a-1 Kevin Wecht, Harvard

  14. GOSAT observations are too sparse to spatially resolve California emissions Correction factors to methane emissions from inversion GOSAT data (CalNex period)) GOSAT (CalNex period) GOSAT (1 year) Each point = 1-10 observations 0.5 1.5 Kevin Wecht, Harvard

  15. Potential of TROPOMI and GCIRI for constraining methane emissions Correction factors to EDGAR v4.2 a priori emissions from a 1-year OSSE TROPOMI (global daily coverage) GCIRI (geostationary 1-h return coverage) 0.2 1 5 Kevin Wecht, Harvard

  16. Working with stakeholders at the US state level State-by-state analysis of SCIAMACHY correction factors to EDGARv4.2 emissions with Iowa Dept. of Natural Resources State emissions computed w/EPA tools too low by x3.5; now investigating EPA livestock emission factors Hog manure? 0 1 2 correction factor with New York Attorney General Office State-computed emissions too high by x0.6, reflects overestimate of gas/waste/landfill emissions Large EDGAR source from gas+landfills is just not there Melissa Sulprizio and Kevin Wecht, Harvard

  17. Now on to bromine…

  18. Bromine chemistry in the atmosphere GOME-2 BrO columns Inorganic bromine (Bry) O3 hv BrNO3 Br BrO Halons hv, NO OH HBr HOBr Stratospheric BrO: 2-10 ppt CH3Br Thule Stratosphere VSLS Tropopause (8-18 km) Troposphere TroposphericBrO: 0.5-2 ppt CHBr3 CH2Br2 OH, h Bry Satellite residual [Theys et al., 2011] debromination BrO column, 1013 cm-2 deposition Sea salt industry plankton

  19. Mean vertical profiles of CHBr3 and CH2Br2 From NASA aircraft campaigns over Pacific in April-June Vertical profiles steeper for CHBr3 (mean lifetime 21 days) than for CH2Br(91 days), steeper in extratropics than in tropics Parrella et al. [2012]

  20. Model comparison to HIPPO organobromine data CHBr3 CH2Br2 CH3Br Observed GEOS-Chem No biasfor CHBr3, CH3Br; 10% low bias for CH2Br2 Johan Schmidt, Harvard

  21. Liang et al. [2010] stratospheric Bry model (upper boundary conditions) STRATOSPHERE 36 TROPOSPHERE Global tropospheric Bry budget in GEOS-Chem (Gg Br a-1) 56 Bry 3.2 ppt 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]

  22. Tropospheric Bry cycling in GEOS-Chem Global annual mean loadings in Gg Br [ppt], rates in Gg Br s-1 Gg Br [ppt] • Model includes HOBr+HBr in aq aerosols with  = 0.2, ice with  = 0.1 • Mean daytime BrO = 0.6 ppt; would be 0.3 ppt without HOBr+HBr reaction Parrella et al. [2012]

  23. Comparison to seasonal satellite data for tropospheric BrO[Theys et al., 2011] (9:30 am) model model • TOMCAT has lower =0.02 for HOBr+HBrthan GEOS-Chem, large polar spring source from blowing snow • HOBr+HBr reaction critical for increasing BrO with latitude, winter/spring NH max in GEOS-Chem Parrella et al. [2012]

  24. Effect of Br chemistry on tropospheric ozone Zonal mean ozone decreases (ppb) in GEOS-Chem • Two processes: catalytic ozone loss via HOBr, NOx loss via BrNO3 • Global OH also decreases by 4% due to decreases in ozone and NOx Parrella et al. [2012]

  25. 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 • Model BrO is similar in pre-industrial and present atmosphere (canceling effects) Parrella et al. [2012]

  26. 2-step Hg(0) oxidation (Goodsite et al., 2004; Donohoue et al., 2006) Br,OH Hg(0) + Br ↔ Hg(I) → Hg(II) Atmospheric lifetime of Hg(0) against oxidation to Hg(II) by Br Deposition Emission • GEOS-Chem Br yields Hg(0) global mean tropospheric lifetime of 4 months, consistent with observational constraints • Br in pre-industrial atmosphere was 40% higher than in present-day (less ozone), implying a pre-industrial Hg(0) lifetime of only 2 months •  Hg could have been more efficiently deposited to northern mid-latitude oceans in the past Parrella et al. [2012]

  27. More recent model comparisons to BrO observations OMI tropospheric BrO from cloud slicing (S. Choi, SSAI/NASA GSFC) TORERO - CU AMAX-DOAS over the SE Pacific (R. Volkamer, CU Boulder) Observations GEOS-Chem MAM DJF Upper tropospheric BrO is severely underestimated by GEOS-Chem: major implications for tropospheric ozone, Hg Johan Schmidt, Harvard

  28. Model vs. observed ozone in upper troposphere HIPPO TORERO • Model doesn’t underestimate • ozone transport from stratosphere • but stratospheric Bry/O3 ratio • could still conceivably be too low Johan Schmidt, Harvard

  29. Model vertical profiles over SE Pacific Altitude, km HBr, BrNO3 are major reservoirs in upper troposphere; should they cycle more efficiently to radicals? Johan Schmidt, Harvard

  30. Heterogeneous bromine chemistry currently in GEOS-Chem to be included in GEOS-Chem Can heterogeneous chemistry correct the model underestimate of BrO in UT? Stay tuned! Any other ideas? Johan Schmidt, Harvard

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