ESC seminar No. 30
Establishing Equivalent Resolutions for Global Atmospheric Model Dynamical Cores
- Date
- Monday, November 12, 2007 / 10:00-11:00
- Place
- Seminar Room. 1F, Earth Simulator Research Building
- Speaker
- David L. Williamson (National Center for Atmospheric Research)
- Language
- English
Abstract
The equivalent resolutions for two different global dynamical coresare established when they are coupled to the sub-grid scale parameterization suite of the Community Atmosphere Model (CAM3). One core adopts the common spectral transform formalism, the other adopts a finite volume approach. The equivalent resolutions are established over a range of resolutions employed today for climate models. The comparison is done in the context of the Aqua Planet Experiment. Thus it is based on the characteristics of free, unforced motions, due in large part to the dynamical component driven by the parameterized processes and explicit dissipation. The forced component arising from surface orography and land-ocean-sea-ice contrasts is not considered.
The resolution equivalences are demonstrated for a number of model fields. These include selected time averaged, global and zonal averaged fields, the meridional structure of eddy kinetic energy and eddy temperature variance, the mean meridional eddy transports, the characteristics of tropical wave propagation, and probability density functions of precipitation. These fields indicate that the 2 degree finite volume model is equivalent to T42 spectral transform model, 1 degree is equivalent to T85, and 0.5 degree is equivalent to T170.
This proportional relationship does not hold at lower resolutions.
Contact
Wataru OhfuchiAtmosphere and Ocean Simulation Research Group,
Earth Simulator Center
Tel: 045-778-5765
e-mail:
