A Gray-Radiation Aquaplanet Moist GCM. Part I: Static Stability and Eddy Scale

Abstract In this paper, a simplified moist general circulation model is developed and used to study changes in the atmospheric general circulation as the water vapor content of the atmosphere is altered. The key elements of the model physics are gray radiative transfer, in which water vapor and other constituents have no effect on radiative fluxes, a simple diffusive boundary layer with prognostic depth, and a mixed layer aquaplanet surface boundary condition. This GCM can be integrated stably without a convection parameterization, with large-scale condensation only, and this study focuses on this simplest version of the model. These simplifications provide a useful framework in which to focus on the interplay between latent heat release and large-scale dynamics. In this paper, the authors study the role of moisture in determining the tropospheric static stability and midlatitude eddy scale. In a companion paper, the effects of moisture on energy transports by baroclinic eddies are discussed. The authors ...

[1]  E. Pitcher,et al.  The Significance of Thermodynamic Forcing by Cumulus Convection in a General Circulation Model , 1982 .

[2]  P. Woodward,et al.  The Piecewise Parabolic Method (PPM) for Gas Dynamical Simulations , 1984 .

[3]  Peter H. Stone,et al.  A Simplified Radiative-Dynamical Model for the Static Stability of Rotating Atmospheres , 1972 .

[4]  J. Green,et al.  Transfer properties of the large‐scale eddies and the general circulation of the atmosphere , 1970 .

[5]  G. Craig,et al.  GCM Tests of Theories for the Height of the Tropopause , 1997 .

[6]  I. Troen,et al.  A simple model of the atmospheric boundary layer; sensitivity to surface evaporation , 1986 .

[7]  I. Held,et al.  The role of moisture in the dynamics and energetics of turbulent baroclinic eddies , 2004 .

[8]  J. Scinocca,et al.  Formation and maintenance of the extratropical tropopause by baroclinic eddies , 2001 .

[9]  I. M. Held.  On the Height of the Tropopause and the Static Stability of the Troposphere , 1982 .

[10]  T. Schneider.  The tropopause and the thermal stratification in the extratropics of a dry atmosphere , 2004 .

[11]  Isaac M. Held,et al.  A Scaling Theory for Horizontally Homogeneous, Baroclinically Unstable Flow on a Beta Plane , 1996 .

[12]  P. Rhines.  Waves and turbulence on a beta-plane , 1975, Journal of Fluid Mechanics.

[13]  P. Zurita‐Gotor.  Updraft/downdraft constraints for moist baroclinic modes and their implications for the short-wave cutoff and maximum growth rate , 2005 .

[14]  M. Suárez,et al.  A proposal for the intercomparison of the dynamical cores of atmospheric general circulation models , 1994 .

[15]  M. Juckes.  The Static Stability of the Midlatitude Troposphere: The Relevance of Moisture. , 2000 .

[16]  P. Kushner,et al.  Stratosphere–Troposphere Coupling in a Relatively Simple AGCM: The Role of Eddies , 2004 .

[17]  Gareth P. Williams.  Barotropic instability and equatorial superrotation , 2003 .

[18]  R. Seager,et al.  Air–Sea Interaction and the Seasonal Cycle of the Subtropical Anticyclones* , 2003 .

[19]  G. Craig,et al.  Poleward heat transport by the atmospheric heat engine , 2002, Nature.

[20]  K. Emanuel,et al.  Baroclinic Instability in an Environment of Small Stability to Slantwise Moist Convection. Part I: Two-Dimensional Models , 1987 .

[21]  Christian Franzke,et al.  Is the North Atlantic Oscillation a Breaking Wave , 2004 .

[22]  N. Harnik,et al.  The Effects of Variations in Jet Width on the Growth of Baroclinic Waves: Implications for Midwinter Pacific Storm Track Variability , 2004 .

[23]  K. Emanuel.  Observational evidence of slantwise convective adjustment , 1988 .

[24]  Isaac M. Held,et al.  A Gray-Radiation Aquaplanet Moist GCM. Part II: Energy Transports in Altered Climates , 2007 .

[25]  C. Franzke.  Dynamics of Low-Frequency Variability: Barotropic Mode , 2002 .