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Global simulation of H 2 and HD with GEOS-CHEM

Global simulation of H 2 and HD with GEOS-CHEM Heather Price 1 , Lyatt Jaegl é 1 , Paul Quay 2 , Andrew Rice 2 , and Richard Gammon 2 University of Washington, Seattle Departments of 1 Atmospheric Sciences and 2 Oceanography 2 nd GEOS-CHEM Users Meeting 6 Apr 2005.

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Global simulation of H 2 and HD with GEOS-CHEM

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  1. Global simulation of H2 and HD with GEOS-CHEM Heather Price1, Lyatt Jaeglé1, Paul Quay2, Andrew Rice2, and Richard Gammon2 University of Washington, Seattle Departments of 1Atmospheric Sciences and 2Oceanography 2nd GEOS-CHEM Users Meeting 6 Apr 2005

  2. Annual Global Budget of Molecular Hydrogen in the Troposphere Sources (Tg/yr) MOZARTa Novellic GEOS-CHEMd Hauglustaine Fossil Fuel 16 15±10 20 Biomass Burning 13 16±5 10 Biofuel 5b 4.4 Photochemical 31 40 41 Methane Oxidation 26 ± 9 27 BVOC Oxidation 14 ± 7 14 Ocean 5 3 ± 2 ~ N fixation 5 3 ± 1 ~ Total 70 77 76 Sinks (Tg/yr) MOZART Novelli GEOS-CHEM OHc 15 19 17 Soilsc 55 56 59 Total 70 75 77 Lifetime, years 1.9 2-3 2.1 • aHauglustaine et al., 2002; Photochemical production includes Methane(27.5Tg) and nonmethane hydrocarbons (14.2Tg): Isoprene, Acetone, Monoterpenes, and Methanol. • bAndreae & Merlet, 2001: bf H2/CO = 0.32 per molecule • cNovelli, 1999: bb H2/CO = 0.29, for fossil fuels Novelli uses global CO source of 500Tg/yr from Logan et al., 1981, Pacnya & Graedel, 1995 and WMO, 1995

  3. H2 and HD in the GEOS-CHEM Model Based on the GEOS-CHEM offline CO simulation v5.05.04 Sources H2/CO (per molecule) Fossil Fuels 0.59a Biomass Burning 0.30c Biofuels 0.32b Photochemical yield relative to CO Methane Oxidation 0.50 BVOC Oxidation 0.50 Sinks OHd H2 + OH → H2O + H k = 1.5x10 -13 e-2000/T Soils Uniform Deposition Velocity over land = 0.042 cm/s k • aOliver et al., 1996 CO emission inventory EDGAR • H2/CO (per molecule) = 0.588 or 0.042Tg H2/CO • bAndreae & Merlet, 2001: bf H2/CO = 0.32 or 0.023Tg H2/CO • cNovelli, 1999; bb H2/CO= 0.30 or 0.022Tg H2/CO • d JPL reported average of nine studies detailed in Ravishankara et al., 1981 and in excellent agreement with measurements by Talukdar et al., 1996.

  4. GEOS-CHEM Simulation of H2 Surface (JJA) Surface (DJF) H2 ppbv

  5. Validating the GEOS-CHEM H2 simulation against CMDL H2 Observations Surface (JJA) Surface (DJF) CMDL sites CMDL sites H2 ppbv (Novelli, 1999) Climate Monitoring and Diagnostics Laboratory: ftp://140.172.192.211/ccg/h2/flask/

  6. Correlation (r=0.76) model-obs obs Bias: x100 = 0.45% H2 Interhemispheric Gradient 600 550 500 450 400 GEOS-CHEM model NOAA CMDL observations (1989-2003) ~40 ppbv gradient H2 ppbv GEOS-CHEM H2 simulation vs. CMDL observations 600 550 500 450 400 Spring Summer Autumn Winter Winter % Bias: 1.25 R: 0.67 Spring % Bias: 0.70 R: 0.56 -90 -50 0 50 90 Latitude GEOS-CHEM H2 ppbv Fall % Bias: -0.86 R: 0.71 Summer % Bias: 0.71 R: 0.80 400 450 500 550 600 CMDL H2 ppbv

  7. H2 Seasonal Cycle Barrow (89-03) Bermuda(91-03) Mauna Loa(89-03) 650 600 550 500 450 400 Northern Hemisphere Southern Hemisphere CMDL observations H2 ppbv Model 32.4 N, 64.7 W 19.5 N, 155.6 W 71.3 N,156.6 W 2 4 6 8 10 12 2 4 6 8 10 12 2 4 6 8 10 12 Month Month Month Ascension (89-03) Cape Grim(91-03) Palmer Station(94-03) 650 600 550 500 450 400 H2 ppbv 7.9 S, 14.4 W 40.7 S, 144.7 E 64.9 S, 64.0 W 2 4 6 8 10 12 2 4 6 8 10 12 2 4 6 8 10 12 Month Month Month

  8. H2 Vertical Profiles Nov 2002-Aug 2004 Poker Flat, Alaska 65.07N, -147.29W Cook Islands -21.25S, –159.83W Park Falls, Wisc. 45.93N,-90.27W March April May 4 2 0 Soil Sept Oct Nov Model Observations km km 4 2 0 km 400 500 600 400 500 600 400 500 600 H2 (ppbv) H2 (ppbv) H2 (ppbv)

  9. Adding hydrogen isotope (HD) to the GEOS-CHEM model • Model development based on measured ratios of HD/H2 for various sources, sinks, and reservoirs • Will give additional constraint to the H2 budget sources and sinks • Determine the contributions of sources and sinks • to atmospheric dD and interhemispheric gradient (Gerst & Quay, 2000, 2001)

  10. Deuterium Source & Sink Signatures δD of the global Troposphere = 130 %o Term H2 Tg/yr dD%oa Fossil Fuels 20 -196 Biomass Burning 10 -293 Biofuels 4.4 -293 Methane Oxidation 28 156 BVOC Oxidation 14 156 OH Sink 17 0.601 Soil Sink 60 0.943 Soil, fossil fuel, and biomass burning fractionation: Gerst & Quay, 2001 OH fractionation: Ehhalt et al., 1989

  11. Surface H2 and dD Annual dD H2 ppbv dD (%0)SMOW JJA

  12. Biofuels & Fossil Fuels DJF dD Model, Surface & Cruise Observations Barrow Cheeka Peak 1998,2002,2004 Ocean Cruise Observations dD (%0 vs SMOW)

  13. Additional enrichment from Stratosphere? dD vs. Latitude dD (atmos) asinks ~40 %0 gradient dD Observational Data from Rice & Quay, 2004 and Gerst, & Quay, 2001.

  14. Summary • GEOS-CHEM captures well the H2 and dD latitudinal gradient (H2~40ppbv, dD~40%o) and seasonality. • Soil Sink uncertainty: incorporate soil moisture, precipitation, to better constrain soil deposition • Next, help explain the dD observations of stratospheric enrichment (Röckmann et al., 2003; Rahn et al., 2003) • Could dD measurements • be used to constrain • Asian biofuel emissions? Fossil Fuels Biofuel + Fossil Fuel Biomass Burning DJF dD

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