Atmospheric Chemical Transport Models - Examples and Measurement Systems

12． Examples of Chemical Transport Models, contd. (b) NCAR Community Climate Model (CCM)(1994) CCM2 characteristics (P. Rasch & D. Williamson) σ= Vertical: P Ps ( terrain following below 100mb level )⎫⎪ P above 100mb level ( lid at 2.9mb ) ⎬18 levels ⎪ ⎭ Horizontal: Spectral (T42 with 128 longitude and 64 latitude (gaussianquadrature grid) Time: Δt = 20 min , semi-implicit leap-frog Transport: semi-Lagrangian* scheme for all chemical species (including H 2 O ) applied on the above grid Subgrid-scale processes: planetary boundary layer includes eddy diffusivity and counter-gradient transport, bulk atmosphere includes vertical diffusion scheme and gravity wave effects, moist convection by the three-level (entrainment, condensation, detrainment) “Hack” scheme *Semi-Lagrangian computes current states from past states using integration of Lagrangian form of continuity equation along a back trajectory with the point of origin values obtained by interpolation from adjacent grids point of origin (ξ) ⎛ Pi − Li ⎞ ⎜ ∫ ⎜ M ] ⎟⎟dt trajectory ⎝ [ ⎠ dX i Pi − Li (derived by integrating ) = dt [M] X ijn +1 = X inξ + Examination of tracer transport in the NCARCCM2 by comparison of CFCl3 simulations with ALE/GAGE observations Images removed due to copyright considerations. See Figure 1, Figure 2 and Figure 3. Hartley, D.E., D.L. Williamson, P.J. Rasch, and R.G. Prinn, Examination of tracer transport in the NCARCCM2 by comparison of CFCl3 simulations with ALE/GAGE observations. Journal of Geophysical Research, 99, 12885–12896, 1994. Images removed due to copyright considerations. See Figure 4, Figure 5 and Figure 17. Hartley, D.E., D.L. Williamson, P.J. Rasch, and R.G. Prinn, Examination of tracer transport in the NCARCCM2 by comparison of CFCl3 simulations with ALE/GAGE observations. Journal of Geophysical Research, 99, 12885–12896, 1994. Images removed due to copyright considerations. See Figure 6, Figure 10, Figure 12, Figure 14 and Figure 15. Hartley, D.E., D.L. Williamson, P.J. Rasch, and R.G. Prinn, Examination of tracer transport in the NCARCCM2 by comparison of CFCl3 simulations with ALE/GAGE observations. Journal of Geophysical Research, 99, 12885– 12896, 1994. (c) MODEL for ATMOSPHERIC TRANSPORT & CHEMISTRY (MATCH) 2.8º x 2.8º (T42) 28 Vertical (sigma) Levels: 1000 to 2.9mb 40 minute time-step (Semi-L. or mass conserving SPITFIRE) NCEP Reanalysis Meteorology Chemical Studies Include: Rn, CCl3F, SF6 Ozone, Sulfur Chemistry Aerosols, Dust R. G. Prinn,12.806: Atmospheric Physics & Chemistry, April 27, 2006 Methane Simulations using MATCH: Y. Chen, Ph.D. Thesis, MIT,2004 METHANE SOURCE Total Range Tg/yr Type Data Source for Spatial Distribution Wetlands 151 115-260 Seas Fung et al. (1991),Matthews et al. (1987); GISS Animals 103 55-110 Aseas Olivier et al. (1999),Lerner et al. (1988); EDGAR3.0 Rice 92 30-120 Seas Matthews et al. (1991); GISS: Kreileman et al. (1994)) Waste 65 40-90 Aseas Olivier et al. (1999),Subak et al. (1992); EDGAR3.0 Natural Gas 51 30-75 Aseas Olivier et al. (1999),Sagers et al. (1990); EDGAR3.0 Coal 39 30-75 Aseas Olivier et al. (1999), Smith et al. (1992); EDGAR3.0 Biomass Burning Termites Other Anthro. 30 10-70 Seas Hao et al. (1993),Hao et al. (1994); NASA 23 36 1-40 Aseas Fung et al. (1991); GISS Aseas Olivier et al. (1999); EDGAR3.0 TOTAL (Tg/yr) 590* 500-600 * Determined by OH magnitude CH4 Reference Emissions Distribution (Annual Mean) Image removed due to copyright considerations. See Figure 3. Chen, Y.-H. and R.G. Prinn, Atmospheric modeling of high-frequency methane observations: Importance of interannually varying transport. Journal of Geophysical Research, 110, D10303, doi: 10.1029/2004JD005542, 2005.