modeling air movement in the firn at wais-d

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Modeling Air Movement in the Firn at WAIS-D. Mark Battle Bowdoin College. WAIS-D meeting NICL July 16, 2006. Possible firn modeling strategies:. Forward model, diffusion only ( Schwander etc. ) Inverse model, diffusion only ( Butler et al.1999) - PowerPoint PPT Presentation

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  • Modeling Air Movementin the Firn at WAIS-DMark Battle Bowdoin CollegeWAIS-D meetingNICL

    July 16, 2006

  • Possible firn modeling strategies:Forward model, diffusion only (Schwander etc.)Inverse model, diffusion only (Butler et al.1999)Inverse model, diffusion only, ala RommelaireForward model, diffusion & heat (Severinghaus et al. 2000 )Forward model, diffusion & close-off fractionation (Severinghaus & Battle, 2005 )Other approaches?

  • Possible firn modeling strategies:Forward model, diffusion only (Schwander etc.)Inverse model, diffusion only (Butler et al.1999)Inverse model, diffusion only, ala RommelaireForward model, diffusion & heat (Severinghaus et al. 2000 )Forward model, diffusion & close-off fractionation (Severinghaus & Battle, 2005 )Other approaches?

  • Forward model, diffusion onlyWhat are its virtues?SimpleGood reality checkCan determine age profile vs. depth

  • Forward model, diffusion onlyOverviewMeasured density profile

  • Forward model, diffusion onlyOverviewMeasured density profileCalculate porosity and diffusivity

  • Forward model, diffusion onlyOverviewMeasured density profileCalculate porosity and diffusivityTune diffusivity until one species observations are reproduced

  • Forward model, diffusion onlyOverviewMeasured density profileCalculate porosity and diffusivityTune diffusivity until one species observations are reproducedConfirm(?) with other species

  • Forward model, diffusion onlyOverviewMeasured density profileCalculate porosity and diffusivityTune diffusivity until one species observations are reproducedConfirm(?) with other speciesUse it

  • Field-measured density in various cores at WAIS-D

  • Fit to density, used for diffusivity starting-point.

  • How deep is the diffusive column?

  • How deep is the diffusive column?64.84mbs

  • Getting started with CO2

  • Correcting for Gravitational Fractionation

  • Getting started with CO2

  • After Tuning

  • After Tuning

  • Testing with other species

  • Testing with CH4

  • Testing with CH3CCl3

  • Testing with F11

  • Testing with HFC134a

  • Summary of basic forward model:No big surprises!!!

  • Summary of basic forward model:No big surprises!!!Density-based diffusivity requires only minor tweaking

  • Summary of basic forward model:No big surprises!!!Density-based diffusivity requires only minor tweakingXX vs. depth looks generally good for wide range of histories

  • Summary of basic forward model:No big surprises!!!Density-based diffusivity requires only minor tweakingXX vs. depth looks generally good for wide range of historiesGravitational correction needs more data

  • Summary of basic forward model:No big surprises!!!Density-based diffusivity requires only minor tweakingXX vs. depth looks generally good for wide range of historiesGravitational correction needs more dataDCH3CCl3/DCO2 consistent with SPO

  • Summary of basic forward model:No big surprises!!!Density-based diffusivity requires only minor tweakingXX vs. depth looks generally good for wide range of historiesGravitational correction needs more dataDCH3CCl3/DCO2 consistent with SPODF11/DCO2 consistent with theory (and not SPO)

  • Summary of basic forward model:No big surprises!!!Density-based diffusivity requires only minor tweakingXX vs. depth looks generally good for wide range of historiesGravitational correction needs more dataDCH3CCl3/DCO2 consistent with SPODF11/DCO2 consistent with theory (and not SPO)Timing of forcing history crucial (e.g. HFC134a)

  • Summary of basic forward model:No big surprises!!!Density-based diffusivity requires only minor tweakingXX vs. depth looks generally good for wide range of historiesGravitational correction needs more dataDCH3CCl3/DCO2 consistent with SPODF11/DCO2 consistent with theory (and not SPO)Timing of forcing history crucial (e.g. HFC134a)Ready to roll

  • Where to next?Characterizing age spread by depth

  • Where to next?Characterizing age spread by depthYou tell me