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.)

"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

"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

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

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

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

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)

(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?")

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)