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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.

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Presentation on theme: "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."— Presentation transcript:

1 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.)

2 "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

3 "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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5 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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7 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

8 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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17 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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19 (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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22 • 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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