Description of AFES 2: Improvements for High-Resolution and Coupled Simulations

  • Takeshi Enomoto
  • Akira Kuwano-Yoshida
  • Nobumasa Komori
  • Wataru Ohfuchi


This chapter describes the updated version of Atmospheric General Circulation Model for the Earth Simulator (AFES 2). Modifications are intended (1) to increase the accuracy and efficiency of the Legendre transform at high resolutions and (2) to improve the physical performance. In particular, the Emanuel scheme replaces a simplified version of the Arakawa-Schubert scheme for the parametrization of cumulus convection. The Emanuel scheme parametrizes O(100m) drafts within subgrid-scale cumuli and does not have explicit dependency upon the grid size. Therefore the cloud model of the Emanuel scheme allows us to use it at high resolutions of O(10km) where the validity of the ensemble cloud model of the Arakawa-Schubert scheme is questionable. Moreover, 10-year test runs indicate that the use of the Emanuel scheme improve the physical performance at a moderate resolution as well. Anomalies of the geopotential height and zonal winds in the middle to upper troposphere are reduced, although the improvements in terms of the distributions of precipitation and sea-level pressure are not significant. Improvements are attributable to a better vertical structure of temperature in the tropics due to more realistic estimation of mixing of the momentum, temperature, and moisture by the Emanuel scheme.


Atmospheric General Circulation Model Cloud Fraction Contour Interval Convective Precipitation Couple Simulation 
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© Springer Science+Business Media, LLC 2008

Authors and Affiliations

  • Takeshi Enomoto
  • Akira Kuwano-Yoshida
  • Nobumasa Komori
  • Wataru Ohfuchi

There are no affiliations available

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