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Gws in Ultra-fine Resolution Global Atmospheric Models Thanks to: GFDL-SKYHI model folks: J. Mahlman, J. Wilson, R. Hemler, L. Umscheid.. AFES folks: W. Ohfuchi et al. And particularly to: Li Yuan (now at Chase-Manhattan Bank) John Koshyk (now at Toronto-Dominion bank) Yoshiyuki Takahashi (Hokkaido U.)
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"Ultra-fine" AGCM GFDL SKYHI N270-L40 (~T450) AFES T1279-L96 | T639-L48, T639-L24 NASA fvGCM N720-L48 NICAM 3.5 km Icosahedral-L54
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"Ultra-fine" AGCM GFDL SKYHI N270-L40 (~T450) AFES T1279-L96 | T639-L48, T639-L24 NASA fvGCM N720-L48 NICAM 3.5 km Icosahedral-L54
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SKYHI Model Global, hydrostatic primitive equations A-grid-point model, explicit time-marching Model domain: surface-about 80 km Ri-dependent vertical mixing Smagorinsky-type harmonic horizontal mixing Moist convective adjustment
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possible caveats A-grid - poor representation of dispersion relation for short waves, no enstrophy conservation - accumulation of energy...? Interpolation needed for spherical harmonic expansions Moist convective adjustment Smagorinsky diffusion
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AFES Model Global, hydrostatic primitive equations Spectral model, semi-implicit time differencing Model domain: surface to about 55 km Linear biharmonic diffusion Emanuel convection, Modified AS... others
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Dry-dynamical-core Model No latent heat No thermal interaction with surface No topography Thermal forcing only through a Newtonian cooling towards a specified radiative equilibrium which is a function of pressure and latitude (following Held & Suarez, 1994)
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(Nontopographic) Gravity Wave Forcing Can we characterize gravity wave fluxes into the stratosphere in terms of tropospheric circulations? e.g. how much spatial and temporal variability is in the flux (e.g. "90% of flux from 1% of the globe?")
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Topographic drag - comparing detailed simulation with parameterization Review: Garner 2005 JAS Earlier simulations: e.g. Olaffson and Bougeault 1996, 1997 Relation of near tropopause gravity wave fluxes to underlying dry dynamics (Dunkerton and Sullivan, 1992; Zhang 2004)
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